brick
Set of rules. Tolerances crushed stone base Sp excavation snip 3.02 01 87

Set of rules. Tolerances crushed stone base Sp excavation snip 3.02 01 87

Notes

1 The timing of geotechnical monitoring should be extended in the absence of stabilization of changes in the controlled parameters.

2 The frequency of fixing the monitored parameters should be linked to the schedule of construction and installation works and can be adjusted (i.e., performed more often than indicated in the geotechnical monitoring program) if the values of the controlled parameters exceed the expected values (including their changes that exceed the expected trends) or identify other dangerous deviations.

3 For unique newly erected and reconstructed structures, as well as during the reconstruction of historical, architectural and cultural monuments, geotechnical monitoring should be continued for at least two years after construction is completed.

4 Fixation of controlled parameters during geotechnical monitoring of the building envelope of a pit with a depth of more than 10 m, as well as at a shallower pit depth in case the controlled parameters exceed the calculated values, must be performed at least once a week.

5 Geotechnical monitoring of the soil mass surrounding the newly erected or reconstructed structure, after the completion of the construction of its underground part and with the stabilization of changes in the controlled parameters of the soil mass and the surrounding buildings, it is allowed to conduct once every three months.

6 In the presence of dynamic effects, it is necessary to measure the level of oscillations of the bases and structures of newly erected (reconstructed) structures and the surrounding buildings.

7 Fixation of changes in the controlled parameters of the state of building structures, incl. damaged, geotechnical monitoring of structures of the surrounding buildings should be carried out, incl. according to the results of periodic visual-instrumental examinations.

8 The requirements of Table 12.1 must be followed, incl. during geotechnical monitoring of structures of the surrounding development located in the zone of influence of the installation of underground utilities, which is determined in accordance with the requirements of 9.33, 9.34.

9 Geotechnical monitoring of newly erected or reconstructed structures on sites of a hazardous category in terms of karst-suffosion must be carried out during the entire period of construction and operation of structures. The term for performing geotechnical monitoring of newly erected or reconstructed structures in areas of a potentially dangerous category in terms of karst-suffosion should be determined in the geotechnical monitoring program, but be at least five years after construction is completed.

RUSSIAN JOINT STOCK COMPANY
GAZPROM

SYSTEM OF REGULATORY DOCUMENTS IN CONSTRUCTION

CODE OF CONSTRUCTION RULES
MAIN GAS PIPELINES

CODE OF RULES FOR CONSTRUCTION
LINEAR PART OF GAS PIPELINES

EARTHWORKS

SP 104-34-96

Approved by RAO Gazprom

(Order dated September 11, 1996 No. 44)

Moscow

1996

SP 104-34-96

Set of rules

Code of Rules for the Construction of Main Gas Pipelines

Code of the regulations on construction of trunk gas pipelines

Date of introduction 1.10.1996

Earthworks production

Developed by the Highly Reliable Pipeline Transport Association, RAO Gazprom, JSC Rosneftegazstroy, JSC VNIIST, JSC NGS-Orgproektekonomika.

Under the general editorship

acad. B.E. Patona, Ph.D. tech. Sciences V.A. Dinkov. prof. O.M. Ivantsova

INTRODUCTION

The Code of Rules summarizes the results of research and design development, as well as best practices in earthworks, accumulated by construction organizations in domestic and foreign practice in the construction of linear facilities.

This joint venture proposes new methods for the construction of main pipelines in difficult natural and climatic conditions, reflects methods for developing trenches, constructing embankments, drilling holes and wells for pile supports, backfilling trenches taking into account the design parameters of pipelines, the specifics of drilling and blasting operations, including including the parallel laying of multi-line highways on different sections of the route.

This joint venture is intended for specialists in construction and design organizations involved in earthworks during the construction of the linear part of pipelines, as well as in the development of projects for the organization of construction and production of works (POS and PPR).

Terminology

The dump is usually called the soil laid along the trench during its development by earthmoving machines.

Embankments are earthworks intended for laying pipelines when crossing low or difficult terrain, as well as for building a roadbed along them or softening the route profile when planning a construction strip by means of additional soil filling.

Excavations are earthworks arranged by cutting the soil while softening the longitudinal profile of the route and laying roads along the pipeline construction strip.

Semi-dredging-semi-filling - earthworks, combining the features of cutting and embankment, intended for laying pipelines and roads on steep slopes (mainly transverse slopes).

Ditches - structures in the form of linear recesses, usually arranged to drain the construction strip, they are often called drainage or drainage. Ditches that serve to intercept and divert water flowing from the upstream territory and arranged on the uphill side of the earthen structure are called upland. Ditches that serve to drain water and are located along both boundaries of cuts or roads are called ditches.

Ditches laid during the construction of pipelines (ground method) in swamps along the boundaries of the ROW and used to store water are called fire ditches.

Cavaliers are called embankments, filled out of excess soil formed during the development of recesses, and located along the latter.

Reserves are usually called excavations, the soil from which is used for filling adjacent embankments. The reserve is separated from the embankment slope by a protective berm.

Quarry - a specially developed excavation for the use of soil when filling embankments and located at a considerable distance from them.

Channel - a recess of considerable length and filled with water. Channels are usually arranged during the construction of pipelines in swamps and wetlands and serve as a trench for laying pipelines using the alloy method or as a main channel for a drainage network of a drainage system.

The structural elements of the trench are the profile of the trench, the soil dump, the roller above the trench (after it has been backfilled with soil). The structural elements of the embankment are subgrade, ditches, cavaliers and reserves.

The trench profile, in turn, has the following characteristic elements: bottom, walls, edges.

Embankments have: a base, slopes, a sole and edges of slopes, a ridge.

Bed - a layer of loose, usually sandy soil (10-20 cm thick), poured onto the bottom of the trench in rocky and frozen soils to protect the insulating coating from mechanical damage when laying the pipeline in the trench.

Powder - a layer of soft (sandy) soil, poured over a pipeline laid in a trench (20 cm thick), before filling it with loosened rocky or frozen soil to the design mark of the earth's surface.

The overburden layer of soil is a mineral soft top layer of soil that lies above the continental rocks, which is subject to priority removal (opening) from the construction strip, for the subsequent effective development of rock soil by drilling and blasting.

Boreholes - cylindrical cavities in the soil with a diameter of up to 75 mm and a depth of not more than 5 m, formed by drilling rigs for placing explosive charges when loosening solid soils using the drilling and blasting blasthole method (for constructing trenches).

Wells - cylindrical cavities in the soil with a diameter of more than 76 mm and a depth of more than 5 m, formed by drilling machines for placing explosive charges in them during drilling and blasting operations, both for loosening the soil and blasting for dumping when arranging shelves in mountainous areas.

Integrated sequential method - a method for developing trenches mainly in high-strength permafrost soils for ballasted pipelines with a diameter of 1420 mm, which consists in sequential passage along the trench alignment of several types of rotary trench excavators, or rotary excavators of the same type with different parameters of the working body for constructing a trench of a design profile (up to 3 3m).

Technological gap - the distance along the front between the grips of the production of certain types of work of the technological process of constructing a linear part of the main pipeline within the right of way (for example, a technological gap between preparatory and earthworks, between welding and installation and insulation and laying, and during earthworks in rocky soils gap between teams for overburden, drilling, blasting and excavation of trenches in soils loosened by the explosion).

Operational quality control of work - a continuous technological process of quality control, carried out in parallel with the implementation of any construction and installation operation or process, is carried out in accordance with the technological maps of operational quality control developed for all types of work on the construction of the linear part of the main pipelines.

The technological map of the step-by-step quality control of earthworks reflects the main provisions on the technology and organization of step-by-step control, technological requirements for machines, determines the main processes and operations that are subject to control, controlled indicators that are characteristic of earthworks, the composition and types of control, as well as forms of executive documentation, where the test results are recorded.

1. General Provisions

1.1. The technology of the entire complex of earthworks, including the engineering preparation of the construction strip, in order to comply with the required dimensions and profiles of earthworks, as well as regulated tolerances during earthworks, must be carried out in accordance with the Project, developed taking into account the requirements of current regulatory documents:

¨ "Main pipelines" (SNiP III-42-80);

¨ "Organization of construction production" (SNiP 3.01.01-80);

¨ Earthworks. Bases and Foundations” (SNiP 3.02.01-87);

¨ "Norms of Land Acquisition for Main Pipelines" (SN-452-73) Fundamentals of Land Legislation of the USSR and Union Republics;

¨ “Construction of main pipelines. Technology and Organization” (VSN 004-88, Minneftegazstroy, P, 1989);

¨ RF Law on Environmental Protection;

¨ Technical Rules for blasting on the day surface (M., Nedra, 1972);

¨ Instructions on the technology of blasting in frozen pounds near existing steel underground main pipelines (VSN-2-115-79);

¨ This Code of Rules.

Detailed development of technology and organizational measures is carried out in the preparation of technological maps and projects for the production of works for specific production processes, taking into account the specifics of the relief and soil conditions of each section of the pipeline route.

1.2. Earthworks should be carried out with the provision of quality requirements and with mandatory operational control of all technological processes. It is recommended that all subdivisions for the production of earthworks be provided with step-by-step quality control cards, which are developed in the development of POS and PPR, schemes for integrated mechanization for the construction of main pipelines by design organizations of the industry.

1.3. Excavation work must be carried out in compliance with the Safety Rules, industrial sanitation and the latest achievements in the field of labor protection.

The whole range of earthworks during the construction of pipelines is carried out in accordance with the projects for the organization of construction and work.

1.4. The technology and organization of earthworks should provide for the flow of their production, year-round performance, including on difficult sections of the route, without a significant increase in their labor intensity and cost, while maintaining the specified pace of work. The exception is work on permafrost soils and wetlands of the Far North, where work is recommended to be done only during the period of soil freezing.

1.5. Management and management of labor protection, as well as responsibility for ensuring the conditions for compliance with labor protection requirements in specialized divisions, are recommended to be assigned to managers, chiefs and chief engineers of these organizations. At work sites, the heads of sections (columns), foremen and foremen are responsible for compliance with these requirements.

1.6. Construction machinery and equipment for earthworks must comply with the technical conditions of operation, taking into account the conditions and nature of the work performed; in northern regions with low air temperatures, it is recommended to mainly use machines and equipment in the northern version.

1.7. During the construction of main pipelines, lands provided for temporary use must be brought into line with the requirements of the on-farm land management project of the relevant land users:

· in the production of earthworks, it is not recommended to use techniques and methods that contribute to flushing, blowing and sinking of soils and soils, the growth of ravines, erosion of sands, the formation of mudflows and landslides, salinization, waterlogging of soils and other forms of loss of fertility;

· when draining the right of way by open drainage, discharge of drainage water into sources of water supply for the population, medical water resources, places of recreation and tourism should not be allowed.

2. Production of earthworks. Land reclamation works

2.1. It is recommended to carry out work on the removal and restoration of the layer within the construction strip in accordance with a special land reclamation project.

2.2. The land reclamation project should be developed by design organizations taking into account the specifics of specific sections of the route and be agreed with the land users of these sections.

2.3. Fertile lands are brought into a usable condition, as a rule, in the process of construction work on the pipeline, and if this is not possible, no later than within a year after the completion of the entire complex of works (as agreed with the land user). All work must be completed within the period of land acquisition for construction.

2.4. In the land reclamation project, in accordance with the conditions for the provision of land plots for use and taking into account local natural and climatic features, the following should be determined:

¨ borders of lands along the pipeline route, where reclamation is required;

¨ the thickness of the removed fertile soil layer for each site subject to reclamation;

Rice. Schematic diagram of the right-of-way during the construction of main pipelines

A - the minimum width of the strip in which the fertile soil layer is removed (the width of the trench along the top plus 0.5 m in each direction)

¨ the width of the reclamation zone within the ROW;

¨ the location of the dump for temporary storage of the removed fertile soil layer;

¨ methods of applying a fertile soil layer and restoring its fertility;

¨ permissible excess of the applied fertile soil layer above the level of undisturbed lands;

¨ methods of compaction of loosened mineral soil and fertile layer after backfilling of the pipeline.

2.5. Work on the removal and application of the fertile soil layer (technical reclamation) is carried out by the construction organization; restoration of soil fertility (biological reclamation, including fertilization, sowing of grasses, restoration of moss cover in the northern regions, plowing of fertile soils and other agricultural work) is carried out by land users at the expense of funds provided for by the estimate for reclamation included in the summary construction estimate.

2.6. When developing and agreeing on a land reclamation project for a pipeline laid parallel to an existing gas pipeline, one should take into account its actual position in the plan, the actual depth of occurrence and technical condition, and based on these data, develop design solutions that ensure the safety of the existing pipeline and the safety of work in accordance with "Instructions for the performance of work in the protected zone of main pipelines" and the current safety regulations.

2.7. When laying a pipeline parallel to an existing pipeline, it should be taken into account that the operating organization, before starting work, must mark the location of the axis of the existing pipeline on the ground, identify and mark dangerous places with special warning signs (areas of insufficient deepening and sections of the pipeline that are in poor condition). During the period of work near the existing pipelines or at the intersection with them, the presence of representatives of the operating organization is necessary. As-built documentation for covert work should be drawn up according to the forms given in VSN 012-88, part II.

2.8. The technology of work on the technical reclamation of disturbed lands during the construction of main pipelines consists in removing the fertile soil layer before the start of construction work, transporting it to a temporary storage site and applying it to the restored lands upon completion of construction work.

2.9. In the warm season, the removal of the fertile soil layer and its transfer to the dump should be carried out with a rotary reclamator of the ETR 254-05 type, as well as bulldozers (D-493A, D-694, D-385A, D-522, DZ-27S types) longitudinally transverse passages with a layer thickness of up to 20 cm and transverse passages with a layer thickness of more than 20 cm. With a fertile layer thickness of up to 10 - 15 cm, it is recommended to use motor graders to remove and move it to the dump.

2.10. The removal of the fertile soil layer should be carried out for the entire design thickness of the reclamation layer, if possible, in one pass or in layers in several passes. In all cases, mixing of the fertile soil layer with mineral soil should not be allowed.

Excess mineral soil formed as a result of the displacement of the volume when laying the pipeline into the trench, in accordance with the project, can be evenly distributed and planned on the strip of the removed fertile soil layer (before applying the latter) or taken out of the construction strip to specially designated places.

The removal of excess mineral soil is carried out according to two schemes:

1. After backfilling the trench, the mineral soil is evenly distributed by a bulldozer or motor grader over the strip to be recultivated, then after compaction, the soil is cut with scrapers (D-357M, D-511C, etc.) to the required depth in such a way as to ensure the allowable excess the level of the applied fertile soil layer above the surface of undisturbed lands. The soil is transported by scrapers to the places specially indicated in the project;

2. Mineral soil after leveling and compaction is cut and moved by a bulldozer along the strip and placed in order to increase the efficiency of its loading onto transport in special piles up to 1.5 - 2.0 m high with a volume of up to 150 - 200 m3 from where it is taken by single-bucket excavators (EO type -4225, equipped with a bucket with a straight shovel or grab), or single-bucket front-end loaders (type TO-10, TO-28, TO-18) are loaded into dump trucks and taken out of the construction strip to places specially specified in the project.

2.11. If, at the request of land users, the project also provides for the removal of the fertile soil layer outside the construction strip to special temporary dumps (for example, on especially valuable lands), then its removal and transportation to a distance of up to 0.5 km should be carried out by scrapers (type DZ-1721).

When removing soil over a distance of more than 0.5 km, dump trucks (such as MAZ-503B, KRAZ-256B) or other vehicles should be used.

In this case, it is recommended to load the fertile layer (also pre-shifted into piles) onto dump trucks using front-end loaders (TO-10, D-543 types), as well as single-bucket excavators (EO-4225 type) equipped with a bucket with a front shovel or grab. Payment for all these works should be provided for in the additional estimate.

2.12. The removal of the fertile soil layer, as a rule, is carried out before the onset of stable negative temperatures. In exceptional cases, in agreement with land users and authorities exercising control over land use, it is allowed to remove the fertile soil layer in winter conditions.

When performing work on the removal of the fertile soil layer in the winter season, it is recommended to develop the frozen fertile soil layer with bulldozers (type DZ-27S, DZ-34S, International Harvester TD -25S) with preliminary loosening of it with three-tooth rippers (type DP-26S, DP -9S, U-RK8, U-RKE, International Harvester TD-25S), Caterpillar rippers (model 9B) and others.

Loosening should be carried out to a depth not exceeding the thickness of the removed fertile soil layer.

When loosening the soil with tractor rippers, it is recommended to use a longitudinally rotary technological scheme.

In winter, rotary trench excavators (ETR-253A, ETR-254, ETR-254AM, ETR-254AM-01, ETR-254-05, ETR-307, ETR-309) can be used to remove and move the fertile soil layer in winter.

The immersion depth of the rotor in this case should not exceed the thickness of the removed fertile soil layer.

2.13. Backfilling of the pipeline with mineral soil is carried out at any time of the year immediately after its laying. Rotary trenchers and bulldozers can be used for this.

In the warm season, after filling the pipeline with mineral soil, it is compacted with vibration compactors of the D-679 type, pneumatic rollers or multiple (three to five times) passes of caterpillar tractors over the pipeline filled with mineral soil. The compaction of mineral soil in this way is carried out before filling the pipeline with the transported product.

2.14. In winter, artificial compaction of mineral soil is not carried out. The soil acquires the required density after thawing for three to four months (natural compaction). The compaction process can be accelerated by wetting (soaking) the soil with water in a backfilled trench.

2.15. The application of a fertile soil layer should be carried out only in the warm season (with normal humidity and sufficient bearing capacity of the soil for the passage of cars). For this, bulldozers are used, working in transverse strokes, moving and leveling the fertile soil layer. This method is recommended when the topsoil is over 0.2 m thick.

2.16. If it is necessary to transport the fertile soil layer to the place of application from dumps located outside the construction strip and at a distance of up to 0.5 km from it, scrapers (DZ-1721 type) can be used. With a transportation distance exceeding 0.5 km, the fertile soil layer is delivered using dump trucks, followed by leveling it with bulldozers operating in oblique or longitudinal passages.

Leveling of the fertile soil layer can also be carried out by motor graders (type DZ-122, DZ-98V, equipped in the front with a blade-blade).

Bringing land plots into a suitable condition is carried out in the course of work, and if this is not possible - no later than within a year after completion of work.

2.17. Control over the correctness of the performance of work in accordance with the land reclamation project is carried out by the bodies of state control over the use of land on the basis of a regulation approved by the Government. The transfer of restored lands to land users must be formalized by an act in the prescribed manner.

3. Earthwork under normal conditions

Specific parameters of earthworks are determined by working drawings.

The depth of the trench is set from the conditions of protecting the pipeline from mechanical damage when vehicles, construction and agricultural vehicles move through it. The depth of the trench when laying main pipelines is taken equal to the diameter of the pipe plus the required amount of backfilling of soil above it and is assigned by the project. At the same time, it must be (according to SNiP 2.05.06-85) not less than:

with a diameter of less than 1000 mm .............................................. ....................................... 0.8 m;

with a diameter of 1000 mm or more .............................................. .................................................. 1.0 m;

· in swamps or peat soils to be drained .................................................. 1.1 m;

· in sand dunes, counting from the lower marks of inter-dune foundations... 1.0 m;

in rocky soils, swampy areas in the absence of travel

motor transport and agricultural machinery .................................................................. ....... 0.6 m.

The minimum width of the trench at the bottom is assigned by SNiP and is taken at least:

¨ D + 300 mm - for pipelines with a diameter of up to 700 mm;

¨ 1.5D - for pipelines with a diameter of 700 mm or more, subject to the following additional requirements:

for pipelines with a diameter of 1200 and 1400 mm when digging trenches with slopes not steeper than 1:0.5, the width of the trench along the bottom can be reduced to a value of D + 500 mm, where D is the nominal diameter of the pipeline.

When excavating soil with earth-moving machines, it is recommended to take the width of the trench equal to the width of the cutting edge of the working body of the machine, adopted by the construction organization project, but not less than that indicated above.

When ballasting the pipeline with weighting loads or fixing it with anchor devices, the width of the trench along the bottom must be taken at least 2.2 D, and for a pipeline with thermal insulation it is established by the project.

It is recommended to take the width of the trench along the bottom in curved sections from forced bending bends equal to twice the width in relation to the width in straight sections.

· a written permit for the right to excavate in the area of underground utilities, issued by the organization responsible for the operation of these utilities;

· a project for the production of earthworks, in the development of which standard technological maps are used;

Work order for the crew of the excavator (if the work is carried out in conjunction with bulldozers and rippers, then for the drivers of these machines) for the production of work.

3.3. Before developing a trench, it is necessary to restore the alignment of the trench axis. When developing a trench with a single-bucket excavator, poles are placed along the axis of the trench in front of the machine and behind along an already dug trench. When digging with a rotary excavator, a vertical sight is installed on the front of it, which allows the driver, focusing on the installed milestones, to keep to the design direction of the route.

3.4. The profile for the trench must be made so that the laid pipeline along the entire length of the lower generatrix is in close contact with the bottom of the trench, and at the turning angles it is located along the line of elastic bending.

3.5. At the bottom of the trench, do not leave fragments of steel, gravel, hard lumps of clay and other objects and materials that can damage the insulation of the pipeline being laid.

3.6. The development of the trench is carried out by single-bucket excavators:

¨ in areas with pronounced hilly terrain (or strongly rugged), interrupted by various (including water) obstacles;

¨ in rocky soils loosened by drilling and blasting;

¨ on sections of curved pipeline inserts;

¨ when working in soft soils with the inclusion of boulders;

¨ in areas of high humidity and swamps;

¨ in watered soils (on rice fields and irrigated lands);

¨ in places where it is impossible or impractical to use bucket-wheel excavators;

¨ in difficult areas specially defined by the project.

To develop wide trenches with slopes (in heavily watered, loose, unstable soils), single-bucket excavators equipped with a dragline are used in the construction of pipelines. Earth-moving machines are equipped with a reliable functioning sound alarm. The signaling system must be familiar to all work crews serving these machines.

In areas with a calm terrain, on gently sloping hills, on soft foothills and on soft, lingering mountain slopes, work can be performed by rotary trench excavators.

3.7. Trenches with vertical walls can be developed without fastening in soils of natural moisture with an undisturbed structure in the absence of groundwater to a depth (m):

· in bulk sandy and gravelly soils......... no more than 1;

· in sandy loam .............................................. ........................ no more than 1.25;

in loams and clays .............................................. ...... no more than 1.5;

in especially dense non-rocky soils ....................... no more than 2.

When developing trenches of great depth, it is necessary to arrange slopes of various positions depending on the composition of the soil and its moisture content (Table).

Table 1

Permissible steepness of slopes of trenches

	The ratio of the height of the slopes to its occurrence at the depth of the excavation, m

Bulk natural moisture
Sandy and gravel wet (unsaturated)

Loam

Loess dry
Rocky on the plain

3.8. In waterlogged, clayey soils with rain, snow (melt) and groundwater, the steepness of the slopes of pits and trenches is reduced compared to that indicated in Table. up to the angle of repose. The manufacturer of works draws up a decrease in the steepness of slopes by an act. Forest-like and bulk soils become unstable when waterlogged, and during their development, wall fastening is used.

3.9. The steepness of the slopes of the trenches for the pipeline and the pits for the installation of pipeline fittings is taken according to the working drawings (in accordance with the table). The steepness of the trench slopes in swamp areas is taken as follows (table):

table 2

The steepness of the trench slopes in swamp areas

3.11. On linear works in the course of digging trenches for pipelines, in accordance with the working drawings, pits are developed for taps, condensate collectors and other technological units with dimensions of 2 m in all directions from the welded joint of the pipeline with fittings.

Under technological breaks (overlaps), pits are developed with a depth of 0.7 m, a length of 2 m and a width of at least 1 m in each direction from the pipe wall.

When constructing the linear part of the pipelines using the in-line method, the soil excavated from the trench is placed in a dump on one (left in the direction of work) side of the trench, leaving the other side free for the movement of vehicles and construction and installation works.

3.12. To prevent the collapse of the excavated soil into the trench, as well as the collapse of the walls of the trench, the base of the excavated soil dump should be located, depending on the state of the soil and weather conditions, but not closer than 0.5 m from the edge of the trench.

Collapsed soil in the trench can be cleared out with a clamshell excavator just before laying the pipeline.

3.13. The development of trenches with a single-bucket excavator with a backhoe is carried out in accordance with the project without the use of manual cleaning of the bottom (this is achieved by a rational distance of the excavator moving and dragging the bucket along the bottom of the trench), which ensures the elimination of scallops at the bottom of the trench.

3.14. The development of trenches by dragline is carried out by frontal or sidewalls. The choice of development method depends on the size of the trenches along the top, the place where the pound is dumped and the working conditions. Wide trenches, especially on swampy and soft soils, are usually developed with side passages, and ordinary trenches with frontal ones.

When constructing trenches, it is recommended to install the excavator from the edge of the face at a distance that ensures the safe operation of the machines (outside the prism of soil collapse): for dragline excavators with a bucket with a capacity of 0.65 m3, the distance from the edge of the trench to the axis of movement of the excavator (for lateral development) should be not less than 2.5 m. On unstable, weak soils, wooden slides are placed under the undercarriage of the excavator or they work from mobile foam sleds.

When developing trenches with single-bucket excavators with a backhoe and a dragline, it is allowed to sort out soil up to 10 cm; soil shortage is not allowed.

3.15. In areas with a high level of standing groundwater, it is recommended to start trenching from lower places to ensure water runoff and drainage of overlying areas.

3.16. To ensure the stability of the walls of the trench when working in unstable soils with rotary excavators, the latter are equipped with special slopes that allow the development of trenches with slopes (steepness of 1: 0.5 or more).

3.17. Trenches, the depth of which exceeds the maximum digging depth of an excavator of this brand, are developed by excavators in combination with bulldozers.

Earthworks in rocky soils in flat terrain and in mountainous conditions

3.18. Earthworks during the construction of main pipelines in rocky soils in flat terrain with slopes up to 8 ° include the following operations and are performed in a certain sequence:

Removing and moving to a dump for storing a fertile layer or opening a layer covering rocky soils;

loosening of rocks by drilling and blasting or mechanically with its subsequent planning;

· development of loosened soils by a single-bucket excavator;

arrangement of a bed of soft soil at the bottom of the trench.

After laying the pipeline in the trench, the following work is performed:

¨ powdering of the pipeline with loosened soft soil;

¨ installation of jumpers in a trench on longitudinal slopes;

¨ backfilling of the pipeline with rocky soil;

¨ reclamation of the fertile layer.

3.19. After removing the fertile layer, to ensure uninterrupted and more productive work of drillers and drilling equipment for loosening rocky soil, the overburden layer is removed until the rock is exposed. In areas with a soft soil layer thickness of 10 - 15 cm or less, it can not be removed.

During roller drilling of charging holes and wells, soft soil is removed only for the purpose of preserving it or using it for laying a bed or powdering a pipeline.

3.20. Works on removal of overburden soil are carried out, as a rule, by bulldozers. If necessary, these works can be performed with single-bucket or rotary excavators, trench fillers, using them both independently and in combination with bulldozers (combined method).

3.21. The removed soil is laid on the trench berm in order to be able to use it for bedding and powdering. A dump of loosened rocky soil is located behind the dump of overburden soil.

3.22. With a small thickness of rocks or in the case of their strong fracturing, loosening is recommended to be carried out with a tractor ripper.

3.23. Loosening of rocky soils is carried out mainly by methods of short-delayed blasting, in which charge wells (holes) are arranged in a square grid.

In exceptional cases of using the instantaneous blasting method (with wide trenches and pits), wells (holes) should be staggered.

3.24. Refinement of the calculated mass of charges and adjustment of the grid location of holes is carried out by test explosions.

3.25. Explosive work must be carried out in such a way that the rock is loosened to the design trench marks (taking into account the construction of a sand bed by 10–20 cm) and re-blasting is not required for its completion.

This equally applies to the device shelves in an explosive way.

When loosening the soil by explosive method, it is also necessary to ensure that pieces of loosened soil do not exceed 2/3 of the size of the excavator bucket intended for its development. Pieces of large sizes are destroyed by overhead charges.

3.26. Before the development of the trench, a rough layout of the loosened rocky soil is carried out.

3.27. When laying the pipeline, in order to protect its insulating coating from mechanical damage about the irregularities present at the bottom of the trench, a bed of soft soil with a thickness of at least 0.1 m is arranged above the protruding parts of the base.

The bed is made from imported or local overburden soft soil.

3.28. For the construction of the bed, mainly rotary trench and single-bucket excavators are used, and in some cases rotary trench fillers, which develop soft overburden located on the strip next to the pipeline trench, near the roadway, and dump it on the bottom of the trench.

3.29. The soil brought by dump trucks and dumped next to the pipe (on the side opposite to the dump from the trench) is placed and leveled at the bottom of the trench using a single-bucket excavator equipped with a dragline, a scraper, a backhoe, or scraper or belt devices. With a sufficient width of the trench (for example, in the areas of ballasting the pipeline or in the sections of the turn of the route), leveling the backfilled soil along the bottom of the trench can be carried out by small-sized bulldozers.

3.30. To protect the insulating coating of the pipeline from damage by pieces of rock, when backfilling over the pipe, it is recommended to arrange a powder of soft overburden or imported soil with a thickness of at least 20 cm above the upper generatrix of the pipe. Powdering of the pipeline is performed by the same technique as backfilling under the pipeline.

In the absence of soft soil, bedding and powdering can be replaced by a continuous lining of wooden slats or straw, reed, foam, rubber and other mats. In addition, bedding can be replaced by laying bags filled with soft soil or sand on the bottom of the trench at a distance of 2–5 m from one another (depending on the diameter of the pipeline) or by installing a foam bed (spraying the solution before laying the pipeline).

3.31. Earthworks during the construction of main pipelines in rocky soils in mountainous areas include the following technological processes:

arrangement of temporary roads and access roads to the highway;

stripping works;

Shelving arrangement;

development of trenches on the shelves;

backfilling of trenches and the design of the roller.

3.32. When the pipeline route passes along steep longitudinal slopes, their planning is carried out by cutting the soil and reducing the angle of elevation. These works are carried out along the entire width of the strip by bulldozers, which, cutting the soil, move from top to bottom and push it to the foot of the slope outside the construction strip. The trench profile is recommended to be placed not in bulk, but in mainland soil. Therefore, the device of the embankment is possible mainly in the area of the passage of transport vehicles.

Shelf arrangement

3.33. When passing tracks along a slope with a transverse steepness of more than 8 °, a shelf should be arranged.

The design and parameters of the shelf are assigned depending on the diameter of the pipes, the dimensions of the trenches and soil dumps, the type of machines used and the methods of work and are determined by the project.

3.34. The stability of a semi-fill-shelf depends on the characteristics of the bulk soil and the soil of the foot of the slope, the steepness of the slope, the width of the bulk part, and the state of the vegetation cover. For the stability of the shelf, it is torn off with a slope of 3 - 4% towards the slope.

3.35. In sections with a transverse slope of up to 15 °, the development of recesses for shelves in non-rocky and loosened rocky soils is carried out by transverse passages of bulldozers perpendicular to the axis of the route. The completion of the shelf and its layout in this case is carried out by longitudinal passages of the bulldozer with layer-by-layer development of the soil and its movement in the semi-fill.

The development of soil when arranging shelves in areas with a transverse slope of up to 15 ° can also be carried out with longitudinal passages of a bulldozer. The bulldozer first cuts and develops the soil at the transition line by half-cuts into a half-fill. After cutting the soil in the first prism at the outer edge of the shelf and moving it to the bulk part of the shelf, the soil of the next prism remote from the boundary of the transition to the semi-fill (towards the inner part of the shelf) is developed, and then in the next prisms located in the mainland soil - until the profile of the half-cut is fully developed .

For large volumes of earthworks, two bulldozers are used, which are developing the shelf from both sides with longitudinal passages towards each other.

3.36. In areas with a transverse slope of more than 15 °, single-bucket excavators equipped with a front shovel are used to develop loose or non-rocky soil when arranging shelves. The excavator develops the soil within the semi-excavation and pours it into the bulk part of the shelf. During the initial development of the shelf, it is recommended to anchor it with a bulldozer or tractor. The final finishing and layout of the shelf is carried out by bulldozers.

3.37. When arranging shelves and digging trenches in mountainous areas for loosening non-separable rocks, it is possible to use tractor rippers or a drilling and blasting method of development.

3.38. When operating a tractor ripper, it is taken into account that the efficiency of its work increases if the direction of the working stroke is taken from top to bottom downhill and loosening is carried out with the choice of the longest working stroke.

3.39. Methods for drilling boreholes and wells, as well as methods for loading and detonating charges when arranging shelves in mountainous areas and trenches on shelves, are similar to the methods used when developing trenches in rocky soils on flat terrain.

3.40. It is recommended to carry out excavation work on the development of trenches on the shelves ahead of the removal of pipes to the route.

Trenches on shelves in soft soils and heavily weathered rocks are developed by single-bucket and bucket-wheel excavators without loosening. In areas with dense rocky soils, before developing a trench, the soil is loosened by drilling and blasting.

Earth-moving machines in trenching move along a carefully planned shelf; at the same time, single-bucket excavators move in the same way as when constructing trenches in rocky soils on flat terrain, along a deck of metal or wooden shields.

3.41. The dump of soil from the trench is placed, as a rule, at the edge of the slope of the half-ditch on the right side of the shelf along the development of the trench. If the soil dump is located in the travel zone, then for the normal operation of construction machines and mechanisms, the soil is planned along the shelf and rammed with bulldozers.

3.42. On sections of the route with longitudinal slopes up to 15 °, the development of trenches, if there are no transverse slopes, is carried out by single-bucket excavators without special preliminary measures. When working on longitudinal slopes from 15 to 36°, the excavator is pre-anchored. The number of anchors and the method of their fastening is determined by the calculation, which should be part of the project for the production of works.

When working on longitudinal slopes of more than 10 °, to determine the stability of the excavator, it is checked for spontaneous shift (sliding) and, if necessary, anchoring is performed. Tractors, bulldozers, winches are used as anchors on steep slopes. The holding devices are located at the top of the slope on horizontal platforms and connected to the excavator with a cable.

3.43. On longitudinal slopes up to 22 °, excavation with a single-bucket excavator is allowed in the direction both from the bottom up and from the top down the slope.

In areas with a slope of more than 22 °, to ensure the stability of single-bucket excavators, it is allowed: with a straight shovel, work only in the direction from top to bottom along the slope with the bucket forward in the course of work, and with a backhoe - only from top down along the slope, with the bucket back in the course of work.

The development of trenches on longitudinal slopes up to 36 ° in soils that do not require loosening is carried out by single-bucket or rotary excavators, in previously loosened soils - by single-bucket excavators.

The operation of rotary excavators is allowed on longitudinal slopes up to 36 ° when moving them from top to bottom. With slopes from 36 to 45 °, their anchoring is used.

The work of single-bucket excavators with a longitudinal slope of over 22 ° and bucket-wheel excavators over 45 ° is carried out by special methods according to the project for the production of works.

The development of a trench by bulldozers is carried out on longitudinal slopes up to 36 °.

The construction of trenches on steep slopes from 36 ° and above can also be carried out using a tray method using scraper installations or bulldozers.

Backfilling trenches in the mountains

If the soil of the dump is planned along the shelf, then the final backfilling of the pipeline with rocky soil is carried out by a bulldozer or a rotary trencher, the remaining soil is leveled along the construction strip. In the event that the soil is located at the edge on the side of the slope of the half-ditch, then single-bucket excavators, as well as front-end bucket loaders, are used for these purposes.

3.45. The final backfilling of the pipeline on longitudinal slopes is carried out, as a rule, by a bulldozer, which moves along or at an angle to the trench, and can also be carried out from top to bottom along the slope by a trencher with its obligatory anchoring on slopes over 15 °. On slopes greater than 30° in places where the use of mechanisms is not possible, backfilling can be done manually.

3.46. For backfilling of the pipeline laid in trenches developed by the tray method on steep slopes with the soil dump located at the bottom of the slope, scraper trench-fillers or scraper winches are used.

3.47. To prevent washing away of the soil when backfilling the pipeline on steep longitudinal slopes (over 15 °), it is recommended to install jumpers.

Features of earthworks in winter conditions

3.48. Excavation work in winter is associated with a number of difficulties. The main ones are soil freezing to different depths and the presence of snow cover.

When predicting soil freezing to a depth of more than 0.4 m, it is advisable to protect the soil from freezing, in particular, by loosening the soil with single or multi-point rippers.

3.49. In some places of a small area, it is possible to protect the soil from freezing by warming it with wood residues, sawdust, peat, applying a layer of foam styrene, as well as non-woven rolled synthetic materials.

3.50. To reduce the duration of thawing of frozen soil and in order to maximize the use of the fleet of earth-moving machines in warm weather, it is recommended to remove snow from the strip of the future trench during the period when positive temperatures are established.

Trench development in winter

Methods for developing trenches in winter are prescribed depending on the time of excavation, the characteristics of the soil and the depth of its freezing. The choice of a technological scheme for earthworks in winter should provide for the preservation of snow cover on the soil surface until the start of trenching.

3.52. With a soil freezing depth of up to 0.4 m, trenching is carried out as under normal conditions: a rotary or single-bucket excavator equipped with a backhoe bucket with a bucket capacity of 0.65 - 1.5 m3.

3.53. With a soil freezing depth of more than 0.3 - 0.4 m, before working it out with a single-bucket excavator, the soil is loosened mechanically or by drilling and blasting.

3.54. When using the drilling and blasting method for loosening frozen soils, work on the development of trenches is carried out in a certain sequence.

The trench strip is divided into three grips:

¨ zone of work on drilling holes, charging them and blasting;

¨ zone of planning works;

¨ area for the development of loosened soil by an excavator.

The distance between the grippers should ensure the safe conduct of work on each of them.

Borehole drilling is carried out by motor augers, perforators and self-propelled drilling machines.

3.55. When developing frozen soil using tractor rippers with a capacity of 250 - 300 hp. trench development work is carried out according to the following schemes:

1. With a soil freezing depth of up to 0.8 m, the soil is loosened with a rack-mounted ripper to the entire freezing depth, and then it is developed with a single-bucket excavator. Excavation of loosened soil in order to avoid refreezing must be carried out immediately after loosening.

2. With a freezing depth of up to 1 m, work can be carried out in the following sequence:

loosen the soil with a rack-mounted ripper in several passes, then select it with a bulldozer along the trench;

The remaining soil, having a freezing thickness of less than 0.4 m, is developed with a single-bucket excavator.

A trough-shaped trench in which the excavator operates is arranged with a depth of no more than 0.9 m (for an EO-4121 type excavator) or 1 m (for an E-652 excavator or similar foreign excavators) to ensure that the rear of the excavator rotates when unloading the bucket.

3. With a freezing depth of up to 1.5 m, work can be carried out similarly to the previous scheme, with the difference that the soil in the trough must be loosened with a rack ripper before the passage of the excavator.

3.56. The development of trenches in solid frozen and permafrost soils with a freezing depth of the active layer of more than 1 m can be carried out by a complex combined sequential method, i.e. the passage of two or three different types of bucket wheel excavators.

First, a trench of a smaller profile is developed, and then it is increased to design parameters using more powerful excavators.

In complex sequential work, you can use either different brands of bucket-wheel excavators (for example, ETR-204, ETR-223, and then ETR-253A or ETR-254) or excavators of the same model equipped with working bodies of different sizes (for example, ETR-309).

Before the passage of the first excavator, the soil is loosened, if necessary, by a heavy tractor ripper.

3.57. For the development of frozen and other dense soils, buckets of bucket-wheel excavators must be equipped with teeth hardened with wear-resistant overlays or reinforced with hard-alloy plates.

3.58. With a significant thawing depth (more than 1 m), the soil can be developed with two rotary excavators. At the same time, the first excavator develops the top layer of thawed soil, and the second - the layer of frozen soil, laying it behind the thawed soil dump. For the development of water-saturated soil, you can also use a single-bucket excavator equipped with a backhoe.

3.59. During the period of the greatest thawing of the frozen layer (at a thawing depth of 2 m or more), the trench is developed by conventional methods, as in ordinary or marshy soils.

3.60. Before laying the pipeline in a trench, the base of which has uneven frozen ground, a bed 10 cm high is made of thawed loose or finely loosened frozen soil at the bottom of the trench.

3.61. When thawing frozen soil (30 - 40 cm) for subsequent loosening of the frozen layer, it is advisable to first remove it with a bulldozer or a shovel excavator, and then work according to the same schemes as for frozen soils.

Pipeline backfilling

3.62. To protect the insulating coating of the pipeline laid in the trench, backfilling is carried out with loosened soil. If the backfill soil on the parapet is frozen, then it is advisable to powder the laid pipeline to a height of at least 0.2 m from the top of the pipe with imported soft thawed or loosened mechanically or by drilling and blasting frozen soil. Further backfilling of the pipeline with frozen soil is carried out by bulldozers or rotary trench fillers.

Earthworks in swamps and wetlands

3.63. A swamp (from a construction point of view) is an excessively moistened area of the earth's surface, covered with a layer of peat with a thickness of 0.5 m or more.

Areas with significant water saturation with a peat deposit thickness of less than 0.5 m are classified as wetlands.

Areas that are covered with water and do not have peat cover are waterlogged.

3.64. Depending on the patency of construction equipment and the complexity of construction and installation work during the construction of pipelines, swamps are classified into three types:

First- swamps completely filled with peat, allowing the operation and repeated movement of marsh equipment with a specific pressure of 0.02 - 0.03 MPa (0.2 - 0.3 kgf / cm2) or the operation of conventional equipment using shields, sleighs, or temporary roads , providing a decrease in the specific pressure on the surface of the deposit to 0.02 MPa (0.2 kgf/cm2).

Second- swamps completely filled with peat, allowing the work and movement of construction equipment only on shields, sledges or temporary technological roads, providing a decrease in the specific pressure on the surface of the deposit to 0.01 MPa (0.1 kgf / cm2).

Third- swamps filled with spreading peat and water with a floating peat crust (alloy) and without an alga, allowing the operation of special equipment on pontoons or conventional equipment from floating facilities.

Development of trenches for underground pipeline laying in swamps

3.65. Depending on the type of swamp, the method of laying, the time of construction and the equipment used, the following schemes for conducting earthmoving operations in swampy areas are distinguished:

¨ trenches with preliminary excavation;

¨ development of trenches using special equipment, shields or slates, which reduce the specific pressure on the soil surface;

¨ development of trenches in winter;

¨ development of trenches by explosion.

Construction on swamps should be started after a thorough examination of it.

3.66. The development of trenches with preliminary excavation is used when the depth of the peat layer is up to 1 m with an underlying base having a high bearing capacity. The preliminary removal of peat to the mineral soil is carried out by a bulldozer or an excavator. The width of the excavation formed in this case should ensure the normal operation of the excavator moving along the surface of the mineral soil and developing the trench to its full depth. The trench is arranged with a depth of 0.15 - 0.2 m below the design level, taking into account the possible slippage of the slopes of the trench in the period from the moment of development to the laying of the pipeline. When using an excavator for peat removal, the length of the created front of work is assumed to be 40 - 50 m.

3.67. The development of trenches using special equipment, shields or slates, which reduce the specific pressure on the soil surface, is used in swampy areas with a peat deposit thickness of more than 1 m and having a low bearing capacity.

To develop trenches in soft soils, swamp excavators equipped with a backhoe or dragline should be used.

The excavator can also develop a trench while on foam sledges, which move through the swamp with the help of a winch and are located on mineral soil. Instead of a winch, one or two tractors can be used.

3.68. Excavation of trenches in the summer should be ahead of pipeline insulation if carried out in the field. The lead time depends on the characteristics of pounds and should not exceed 3 - 5 days.

3.69. The feasibility of laying pipelines through long swamps in the summer should be justified by technical and economic calculations and determined by the construction organization project.

Deep and long swamps with a low bearing capacity of the peat cover should be passed in winter, and shallow small marshes and wetlands in the summer season.

3.70. In winter, as a result of soil freezing to the full (design) depth of trench development, the bearing capacity of the soil increases significantly, which makes it possible to use conventional earth-moving equipment (rotary and single-bucket excavators) without the use of sledges.

In areas with deep freezing of peat, work should be carried out in a combined way: loosening the frozen layer by drilling and blasting and excavating the soil to the design mark with a single-bucket excavator.

3.71. The development of trenches in swamps of all types, especially in difficult swamps, is advisable to carry out in an explosive way. This method is economically justified in cases where it is very difficult to carry out work from the surface of the swamp, even using special equipment.

3.72. Depending on the type of swamp and the size of the required trench, various options for developing them by explosive methods are used.

In open and lightly forested swamps, when developing canals 3–3.5 m deep, up to 15 m wide at the top, and the peat layer thickness up to 2/3 of the trench depth, elongated cord charges are used from waste pyroxylin gunpowder or waterproof ammonites.

When laying a pipeline in deep swamps covered with forests, it is advisable to develop trenches up to 5 m deep with concentrated charges placed along the axis of the trench. In this case, there is no need for preliminary clearing of the route from the forest. Concentrated charges are placed in charging funnels, formed, in turn, by small borehole or concentrated charges. For this, waterproof ammonites are usually used in cartridges with a diameter of up to 46 mm. The depth of the charging funnel is taken taking into account the location of the center of the main concentrated charge at 0.3 - 0.5 of the channel depth.

When developing trenches up to 2.5 m deep and 6-8 m wide at the top, it is effective to use borehole charges from waterproof explosives. This method can be used on swamps of types I and II both with and without forest. Wells (vertical or inclined) are located along the axis of the trench at a calculated distance from each other in one or two rows, depending on the design width of the trench bottom. The diameter of the wells is 150 - 200 mm. Inclined wells at an angle of 45 - 60 ° to the horizon are used when it is necessary to eject the soil on one side of the trench.

3.73. The choice of explosives, the mass of the charge, the depth, the location of the charges in the plan, the methods of blasting, as well as the organizational and technical preparation for the production of drilling and blasting operations and the testing of explosive materials are set out in the "Technical Rules for Explosive Operations on the Day Surface" and in the "Methodology for calculating explosive parameters during construction of canals and trenches in swamps” (M., VNIIST, 1970).

Backfilling of the pipeline in swamps

3.74. Methods for performing work when backfilling trenches in swamps in the summer depend on the type and structure of the swamps.

3.75. In swamps of types I and II, backfilling is carried out either by swamp bulldozers, when the movement of such machines is ensured, or by dragline excavators on a widened or normal course, moving along the sledges on dumps of soil, previously planned by two passages of the bulldozer.

3.76. The excess soil obtained during backfilling is placed in an over-trench roller, the height of which is determined taking into account the draft. If there is not enough soil for backfilling the trench, it should be developed by an excavator from lateral reserves, which should be laid from the axis of the trench at a distance of at least three of its depths.

3.77. In deep swamps with a fluid consistency of peat, inclusions of sapropelite or covering with drifts (type III swamps), after laying the pipeline on a solid base, it can not be covered.

3.78. Backfilling of trenches in swamps in winter is carried out, as a rule, by bulldozers on widened caterpillars.

Surface laying of the pipeline in the embankment

3.79. The method of erecting embankments is determined by the conditions of construction and the type of earthmoving machines used.

Soil for filling the embankment in flooded areas and in swamps is being developed in nearby quarries located on elevated places. The soil in such quarries is usually more mineralized and therefore more suitable for a stable embankment.

3.80. The development of soil in quarries is carried out by scrapers or single-bucket or rotary excavators with simultaneous loading into dump trucks.

3.81. In floating bogs, when filling the embankment, the floating crust (alloy) of small thickness (no more than 1 m) is not removed, but immersed to the bottom. In this case, if the thickness of the crust is less than 0.5 m, the filling of the embankment directly onto the raft is carried out without the device of longitudinal slots in the raft.

With a raft thickness of more than 0.5 m, longitudinal slots can be arranged in the raft, the distance between which should be equal to the base of the future earth embankment below.

3.82. The slitting should be done by blasting. Powerful rafts before the start of backfilling are destroyed by explosions of small charges laid in a checkerboard pattern on a strip equal to the width of the earthen strip below.

3.83. Embankments through swamps with low bearing capacity are constructed from imported soil with preliminary peat removal at the base. In swamps with a bearing capacity of 0.025 MPa (0.25 kgf / cm2) and more, embankments can be poured without peat directly on the surface or along brushwood lining. In bogs of type III, embankments are dumped mainly on the mineral bottom due to the extrusion of the peat mass by the soil mass.

3.84. It is recommended to build embankments with excavation in swamps with a peat cover thickness of not more than 2 m. The expediency of peat removal is determined by the project.

3.85. In swamps and other watered areas that have water runoff across the embankment, the filling is carried out from well-draining coarse-grained and gravelly sands, gravel, or special culverts are arranged.

· the first layer (25 - 30 cm high above the swamp), delivered by dump trucks, is covered by the pioneer method of sliding. The soil is unloaded at the edge of the swamp, and then pushed towards the embankment by a bulldozer. Depending on the length of the swamp and the conditions of the entrance, the embankment is erected from one or both banks of the swamp;

· the second layer (up to the design mark of the bottom of the pipe) is poured in layers with compaction immediately along the entire length of the transition;

· the third layer (up to the design level of the embankment) is backfilled after the pipeline is laid.

The leveling of the soil along the embankment is carried out by a bulldozer, backfilling of the laid pipeline is carried out by single-bucket excavators.

3.87. Embankments are poured during the construction process, taking into account the subsequent sedimentation of the soil; the amount of settlement is set by the project depending on the type of soil.

3.88. Backfilling of embankments with preliminary removal of peat at the base is carried out in a pioneering way from the “head”, and without peat removal both from the head part and from the plank road located along the axis of the pipeline.

Earthworks in the construction of concreted or ballasted pipelines

3.90. With the underground method of laying a concreted trench gas pipeline, it is necessary to develop the following parameters:

¨ trench depth - comply with the project and be at least Dn + 0.5 m (Dn - outer diameter of the concreted gas pipeline, m);

¨ the width of the trench along the bottom in the presence of slopes of 1: 1 or more - not less than Dn + 0.5 m.

When developing a trench for alloying a pipeline, its width along the bottom is recommended to be at least 1.5 Dn.

3.91. The minimum gap between the load and the trench wall when ballasting the gas pipeline with reinforced concrete weighting loads should be at least 100 mm, or the width of the trench along the bottom when ballasting with loads or fixing with anchor devices is recommended to be at least 2.2 Dn.

3.92. In view of the fact that pipelines concreted or ballasted with reinforced concrete loads are laid in swamps, swampy and watered areas, earthwork methods are similar to earthworks in swamps (depending on the type of swamps and season).

3.93. To develop trenches for pipelines of large diameters (1220, 1420 mm), concreted or ballasted with reinforced concrete loads, the following method can be used: a bucket-wheel excavator in the first pass opens a trench with a width equal to about half the required trench width, then the soil is returned to its place by a bulldozer; then, with the second pass of the excavator, the soil is selected on the remaining unloosened part of the trench and again returned to the trench by a bulldozer. After that, the loosened soil for the entire profile is selected by a single-bucket excavator.

3.94. When laying a pipeline in areas of predicted flooding, ballasted with reinforced concrete weights, in winter conditions, the method of group installation of weights on the pipeline can be used. In this regard, the trench can be developed in the usual way, and widening it for a group of goods can be done only in certain areas.

Earthworks in this case are carried out as follows: a rotary or single-bucket (depending on the depth and strength of the frozen soil) excavator opens a trench of the usual (for a given diameter) width; then the sections of the trench where the cargo groups are to be installed are covered with soil. In these places, on the sides of the developed trench, holes are drilled for explosive charges in one row, so that after blasting the total width of the trench in these places would be sufficient to install weighting loads. Then the soil, loosened by the explosion, is removed by a single-bucket excavator.

3.95. The backfilling of a pipeline that is concreted or ballasted with weights is carried out using the same methods as when backfilling a pipeline in swamps or frozen soils (depending on the conditions of the route and the time of year).

Peculiarities of excavation technology when laying gas pipelines with a diameter of 1420 mm in permafrost soils

3.97. The construction of trenches in the autumn-winter period with a freezing depth of the active layer from 0.4 to 0.8 m using single-bucket excavators of the EO-4123, ND-150 types is carried out after preliminary loosening of the soil with rack rippers of the D-355, D-354 type and others , which loosen the soil to the entire freezing depth in one technological step.

With a freezing depth of up to 1 m, loosening it is carried out by the same rippers in two passes.

With a greater freezing depth, the development of trenches with single-bucket excavators is carried out after preliminary loosening of the soil by drilling and blasting. Boreholes and wells along the trench strip are drilled using drilling machines such as BM-253, MBSH-321, Kato and others in one or two rows, which are charged with explosives and explode. With a freezing depth of the active layer of soil up to 1.5 m, loosening it for the development of trenches, especially those located no further than 10 m from existing structures, is carried out using the borehole method; with a depth of soil freezing more than 1.5 m - by the borehole method.

3.98. When arranging trenches in permafrost soils in winter with their freezing to the entire depth of development, both in swamps and in other conditions, it is advisable to use mainly rotary trench excavators. Depending on the strength of the developed soil, the following technological schemes are used for trenching:

in permafrost soils with a strength of up to 30 MPa (300 kgf / cm2), trenches are developed in one technological step by bucket-wheel excavators of the ETR-254, ETR-253A, ETR-254A6 ETR-254AM, ETR-254-05 types with a bottom width of 2.1 m and maximum depth up to 2.5 m; ETR-254-S - bottom width 2.1 m and depth up to 3 m; ETR-307 or ETR-309 - bottom width 3.1 m and depth up to 3.1 m.

If it is necessary to develop trenches of greater depth (for example, for ballasted gas pipelines with a diameter of 1420 mm), the same excavators, using tractor rippers and bulldozers of the D-355A or D-455A type, develop a trough-shaped excavation 6–7 m wide and up to 0.8 m deep ( depending on the required design depth of the trench), then in this recess, using the appropriate types of bucket-wheel excavators for a given diameter of the pipeline, a trench of the design profile is developed in one technological pass.

in permafrost soils with a strength of up to 40 MPa (400 kgf/cm2), the development of wide-profile trenches for laying loadable pipelines with a diameter of 1420 mm with reinforced concrete weights of the UBO type in areas with a depth of 2.2 to 2.5 m and a width of 3 m is carried out by a rotary trench excavator of the ETR type -307 (ETR-309) in one pass, or by a complex-combined and sequential method.

The development of trenches in such areas by the in-line complex-combined method, first, along the border of one side of the trench, a pioneer trench is developed by a rotary trench excavator of the ETR-254-01 type with a working body width of 1.2 m, which is filled with a bulldozer of the D-355A, D-455A or DZ type -27C. Then, at a distance of 0.6 m from it, a second trench 1.2 m wide is developed by a rotary excavator of the ETR-254-01 type, which is also covered with loosened soil using the same bulldozers. The final development of the design profile of the trench is carried out by a single-bucket excavator of the ND-1500 type, which, simultaneously with the selection of the soil of the pioneer trenches loosened by rotary excavators, also develops the soil pillar between them.

A variant of this scheme in areas of soil with a strength of up to 25 MPa (250 kgf / cm2) can be the use of bucket-wheel excavators of the ETR-241 or 253A type instead of ETR-254-01 for extracting the second pioneer trench. In this case, there are practically no works on the development of the rear sight.

when developing trenches of such parameters in permafrost soils with a strength of 40 to 50 MPa (from 400 to 500 kgf / cm2), the complex of earth-moving machines (according to the previous scheme) additionally includes tractor rack rippers of the D-355, D-455 type for preliminary loosening the top most durable soil to a depth of 0.5 - 0.6 m before the operation of bucket-wheel excavators.

For the development of trenches in soils of higher strength - over 50 MPa (500 kgf / cm2), when loosening and excavation of the soil pillar with a single-bucket excavator is of great difficulty, it is necessary to loosen it by drilling and blasting before the operation of single-bucket excavators. To do this, drilling machines such as BM-253, BM-254 drill a series of holes in the body of the pillar at intervals of 1.5 - 2.0 m to a depth exceeding the design depth of the trench by 10 - 15 cm, which are charged with explosive charges for loosening and explode. After that, excavators of the ND-1500 type excavate all the loosened soil until the design profile of the trench is obtained.

· trenches for pipelines loaded with reinforced concrete weights (UBO type) with a depth of 2.5 to 3.1 m are developed in a certain technological sequence.

In areas with soil strength up to 40 MPa (400 kgf / cm2) and more, at first, tractor rack rippers based on D-355A or D-455A loosen the upper permafrost soil layer on a strip 6–7 m wide to a depth of 0.2–0, 7 m depending on the required final trench depth. After removing the loosened soil with bulldozers in the resulting trough-shaped excavation with a rotary trench excavator of the ETR-254-01 type, a pioneer cut-trench 1.2 m wide is developed along the border of the project trench. After filling this slot with excavated loosened soil, at a distance of 0.6 m from the edge the second pioneer trench is cut by another rotary excavator of the ETR-254-01 type, which is also filled with the help of bulldozers of the D-355, D-455 type. Then, with a single-bucket excavator of the ND-1500 type, a trench of the full design profile is developed simultaneously with the soil of the pillar.

· in areas of heavily icy high-strength permafrost soils with a cutting resistance of more than 50 - 60 MPa (500 - 600 kgf / cm2), trenching should be carried out with preliminary loosening of soils by drilling and blasting. At the same time, depending on the required depth of trenches, drilling of holes in a checkerboard pattern in 2 rows using machines of the BM-253, BM-254 type should be carried out in a trough-shaped recess with a depth of 0.2 (with a trench depth of 2.2 m) to 1.1 m (at a depth of 3.1 m). To eliminate the need for work on the arrangement of a trough-shaped excavation, it is advisable to introduce drilling machines of the MBSH-321 type.

3.99. On sections of the route in permafrost, low-icy soils, where gas pipelines are to be ballasted with mineral soil using NCM devices, it is recommended to take the following trench parameters: bottom width no more than 2.1 m, depth depending on the amount of backfill and the presence of a heat-insulating screen - from 2.4 up to 3.1 m.

The development of trenches in such areas up to 2.5 m deep in soils with a strength of 30 MPa (300 kgf / cm2) is recommended to be carried out on a full profile with rotary trench excavators of the ETR-253A or ETR-254 type. Trenches up to 3 m deep in such soils can be developed by rotary excavators of the ETR-254-02 and ETR-309 types.

In soils with a strength of more than 30 MPa (300 kgf/cm2), mechanized earth-moving complexes for the implementation of the technological scheme described above should additionally include tractor-mounted rippers of the D-355A or D-455A type for preliminary loosening of the most durable upper layer of permafrost soil to a depth of 0 .5 - 0.6 m before the development of the trench profile by rotary excavators of the indicated brands.

In areas with soil strength up to 40 MPa (400 kgf / cm2), it is also possible to use a technological scheme with sequential excavation and development of a trench profile along the axis of the route by two rotary excavators: first ETR-254-01 with a rotor width of 1.2 m, and then ETR -253A, ETR-254 or ETR-254-02, depending on the required trench depth in this area.

For the effective development of wide trenches of ballasted gas pipelines with a diameter of 1420 mm in solid permafrost soils, a sequential-complex method is recommended with two powerful rotary trench excavators of the ETR-309 type (with different parameters of the working body), in which the first excavator equipped with interchangeable unified working bodies with a width of 1.2 ¸ 1.5 and 1.8 ¸ 2.1 m, first cuts a pioneer trench ~ 1.5 m wide, and then the second excavator, equipped with two mounted side rotary cutters, moving sequentially, finalizes it to the design dimensions of 3x3 m required to accommodate the pipeline with ballasting devices.

In soils with a strength of more than 35 MPa (350 kgf/cm2), it is necessary to include preliminary loosening of the upper frozen layer of soil to a depth of 0.5 m using tractor-mounted rippers of the D-355A or D-455A type in the specified sequentially combined technological scheme.

3.100. In areas with the occurrence of especially strong permafrost soils with a strength of 50 MPa or more (500 kgf / cm2), it is recommended to develop trenches with such parameters with single-bucket excavators of the ND-1500 type with preliminary loosening of the frozen layer by drilling and blasting. To drill holes to full depth (up to 2.5 - 3.0 m), it is necessary to use drilling machines such as BM-254 and MBSH-321.

3.101. In all cases, when performing excavation work on trenching in these soil conditions in the summer, in the presence of a thawed top layer of soil, it is removed from the trench strip using bulldozers, after which the trenching work is carried out according to the technological schemes given above, taking into account the design profile of the trench and the strength of the permafrost in this area.

When the top layer of soil thaws, in the event of its transition to a plastic or fluid state, which makes it difficult to conduct earthworks for loosening and developing the underlying permafrost soil, this layer of soil is removed by a bulldozer or a shovel excavator, and then the permafrost soil, depending on its strength, is developed by the above methods.

Embankments on permafrost soils, as a rule, should be built from imported soil mined in quarries. In this case, it is not recommended to take soil for an embankment on the gas pipeline construction site.

A quarry should be arranged (if possible) in loose-frozen soils, since a change in their temperature slightly affects their mechanical strength.

In the process of erection, the embankment must be backfilled, taking into account its subsequent settlement. The increase in its height in this case is set: when performing work in the warm season and filling the embankment with mineral soil - by 15%, when performing work in the winter and filling the embankment with frozen soil - by 30%.

3.102. Backfilling of a pipeline laid in a trench made in permafrost soils is carried out as under normal conditions, if after laying the pipeline immediately after the development of the trench and backfilling (if necessary), the soil of the dump was not subjected to freezing. In the event of freezing of the soil of the dump, in order to avoid damage to the insulating coating of the pipeline, it must be sprinkled with imported thawed fine-grained soil or finely loosened frozen soil to a height of at least 0.2 m from the top of the pipe.

Further backfilling of the pipeline is carried out with a pound of dump using a bulldozer or, preferably, a rotary trencher, which is capable of developing a dump with freezing to a depth of 0.5 m. If the dump is frozen deeper, it must first be loosened mechanically or by drilling and blasting. When backfilling with frozen soil, a soil bead is arranged above the pipeline, taking into account its settlement after thawing.

Drilling of wells and installation of piles for above-ground laying of pipelines

3.103. The method of erecting pile foundations is prescribed depending on the following factors:

¨ permafrost conditions of the route;

¨ time of year;

¨ technology of work performance and results of technical and economic calculations.

Pile foundations in the construction of pipelines in areas of permafrost are usually built from prefabricated piles.

3.104. The construction of pile foundations is carried out depending on the soil conditions in the following ways:

driving piles directly into the plastic-frozen soil or into previously developed leader holes (drilling method);

installation of piles in pre-thawed soil;

installation of piles in pre-drilled and filled with a special solution wells;

installation of piles using a combination of the above methods.

Driving piles into the frozen mass can only be carried out in high-temperature plastic-frozen soils with a temperature above -1 °C. It is recommended to drive piles into such soils with a content of coarse and solid inclusions up to 30% after drilling leader wells, which are formed by immersing special leader pipes (with a cutting edge at the bottom and a hole in the lateral upper part). The leader hole diameter is 50 mm less than the smallest size of the pile cross-section.

3.105. The technological sequence of operations for installing piles in previously developed leader wells is as follows:

¨ the pile driving mechanism clogs the leader to the design mark;

¨ the leader with the core is retrieved by the winch of the excavator, which moves with the leader pipe to the next well, where the whole process is repeated;

¨ the pile is driven into the formed leader hole by the second pile driving mechanism.

3.106. If there are coarse-grained inclusions in the soil (more than 40%), it is not advisable to use leader drilling, since the initial force to extract the leader increases significantly and the core is shedding back into the well.

3.107. In heavy clays and loams, the use of bored piles is also impractical due to the fact that the core in the pipe is wedged and is not forced out of the leader.

Leader wells can be arranged by drilling by thermomechanical, shock-rope or other methods.

3.108. In cases where it is impossible to use bored piles, they are immersed in wells previously drilled by thermomechanical, mechanical or shock-rope drilling machines.

The technological sequence of operations when drilling wells with percussion-rope drilling machines is as follows:

arrange a platform for installing the unit, which must be strictly horizontal. This is especially important when drilling wells on slopes, where the layout of the site for installing the unit and for smooth entry to it is carried out by a bulldozer by raking up snow and watering it with water (for freezing the upper layer); in the summer, the site is planned by a bulldozer;

· a well is drilled with a diameter of 50 mm larger than the largest transverse dimension of the pile;

The well is filled with a sandy-clay mortar heated to 30 - 40 ° C in the volume of approximately 1/3 of the well, based on the complete filling of the space between the pile and the wall of the well (the solution is prepared directly on the track in mobile boilers using drill cuttings with the addition of fine-grained sand in the amount 20 - 40% of the volume of the mixture; it is desirable to deliver gelling water to hot mobile containers or heat it during the work process);

Install the pile in the well with a pipelayer of any brand.

When the pile is driven to the design mark, the solution should be squeezed out to the surface of the earth, which serves as evidence of the complete filling of the space between the walls of the well and the surface of the pile with the solution. The process of drilling a well and driving a pile into a drilled well should not last more than 3 days. in winter and more than 3-4 hours in summer.

3.109. The technology of drilling wells and installing piles using thermomechanical drilling machines is set out in the "Instructions on the technology of drilling wells and installing piles in frozen soils using thermomechanical drilling machines" (VSN 2-87-77, Minneftegazstroy).

3.110. The duration of the process of freezing piles with permafrost soil depends on the season of work, characteristics of frozen soil, soil temperature, pile design, composition of sand-clay mortar and other factors and should be specified in the work design.

Trench backfill

3.111. Before starting work on backfilling the pipeline in any soil, it is necessary:

¨ check the design position of the pipeline;

¨ check the quality and, if necessary, repair the insulating coating;

¨ to carry out the work envisaged by the project to protect the insulating coating from mechanical damage (planning the bottom of the trench, laying the bed, powdering the pipeline with loose soil);

¨ arrange entrances for the delivery and maintenance of the excavator and bulldozer;

¨ obtain written permission from the customer to backfill the laid pipeline;

¨ issue a work order for the production of work to the driver of a bulldozer or trench filler (or the crew of a shovel excavator, if backfilling is performed by an excavator).

3.113. When backfilling the pipeline in rocky and frozen soils, the safety of pipes and insulation from mechanical damage is ensured by powdering over the laid pipeline from soft (thawed) sandy soil to a thickness of 20 cm above the upper generatrix of the pipe, or by installing protective coatings provided by the project.

3.114. Backfilling of the pipeline under normal conditions is carried out mainly by bulldozers and rotary-type trench fillers.

3.115. Backfilling of the pipeline by bulldozers is carried out: straight, oblique parallel, oblique and combined passages. In the cramped conditions of the construction strip, as well as in places with a reduced right of way, work is carried out with oblique parallel and oblique cross passages by a bulldozer or a rotary trench filler.

3.116. If there are horizontal curves on the pipeline, the curved section is first filled up, and then the rest. Moreover, backfilling of a curved section begins from its middle, moving alternately towards its ends.

3.117. In areas of terrain with vertical curves of the pipeline (in ravines, beams, on hills, etc.), backfilling is carried out from top to bottom.

3.118. With large volumes of backfilling, it is advisable to use trench fillers in combination with bulldozers. At the same time, at first, the backfill is carried out with a trench filler, which during the first pass has maximum productivity, and then the remaining part of the dump is shifted into the trench by bulldozers.

3.119. Backfilling of a pipeline laid in a trench with a dragline is carried out in cases where the operation of equipment in the area of the dump is impossible, or at large distances of backfilling with soil. In this case, the excavator is located on the side of the trench opposite the dump, and the soil for backfilling is taken from the dump and poured into the trench.

3.120. After backfilling on non-reclaimed lands above the pipeline, a soil roller is arranged in the form of a regular prism. The height of the roller should match the amount of possible soil settlement in the trench.

On recultivated lands in the warm season, after the pipeline is backfilled with mineral soil, it is compacted with pneumatic rollers or caterpillar tractors by multiple passes (three to five times) over the backfilled pipeline. The compaction of mineral soil in this way is carried out before filling the pipeline with the transported product.

4. Quality control and acceptance of earthworks

4.1. The quality control of earthworks consists in the systematic monitoring and verification of the compliance of the work performed with the design documentation, the requirements of the joint venture in compliance with the tolerances (given in Table ), as well as technological maps as part of the PPR.

Table 3

Permits for the production of earthworks

4.3. Depending on the nature of the operation (process) being performed, operational quality control is carried out directly by performers, foremen, foremen or a special representative-controller of the customer's company.

4.4. Defects identified during the control, deviations from the designs, requirements of the SP, PPR or technological standards for maps should be corrected before the start of subsequent operations (works).

4.5. Operational quality control of earthworks includes:

¨ verification of the correctness of the transfer of the actual axis of the trench with the design position;

¨ verification of marks and lane width for the operation of bucket-wheel excavators (in accordance with the requirements of the project for the production of works);

¨ checking the profile of the bottom of the trench with measuring its depth and design marks, checking the width of the trench along the bottom;

¨ checking the slopes of trenches depending on the structure of the soil specified in the project;

¨ checking the thickness of the backfill layer at the bottom of the trench and the thickness of the pipeline powder layer with soft soil;

¨ control of the thickness of the layer of backfill and dike of the pipeline;

¨ checking the marks of the top of the embankment, its width and the steepness of the slopes;

¨ the size of the actual radii of curvature of the trenches in the sections of horizontal curves.

4.6. The width of trenches along the bottom, including those in sections ballasted with reinforced concrete weights or screw anchor devices, as well as in sections of curves, is controlled by templates lowered into the trench. The strip marks for the operation of rotary excavators are controlled by a level.

The distance from the center line to the trench wall along the bottom in dry sections of the route should be at least half the design width of the trench, this value should not be exceeded by more than 200 mm; in flooded and swampy areas - more than 400 mm.

4.7. The actual turning radius of the trench in plan is determined by the theodolite (the deviation of the actual axis of the trench in a straight section cannot exceed ± 200 mm).

4.8. Compliance of the trench bottom marks with the design profile is checked using geometric leveling. The actual elevation of the trench bottom is determined at all points where the design elevations are indicated in the working drawings, but at least 100, 50 and 25 m - respectively for pipelines with a diameter of up to 300, 820 and 1020 - 1420 mm. The actual elevation of the trench bottom at any point should not exceed the design one and may be less than it by up to 100 mm.

4.9. In the case when the project provides for adding loose soil to the bottom of the trench, the thickness of the leveling layer of loose soil is controlled by a probe lowered from the trench berm. The thickness of the leveling layer must be at least the design; tolerance for layer thickness is given in table. .

4.10. If the project provides for powdering the pipeline with soft soil, then the thickness of the layer of powder laid in the trench of the pipeline is controlled by a measuring ruler. The thickness of the powder layer is at least 200 mm. Allowed deviation of the layer thickness within the limits specified in table. .

4.11. The marks of the recultivated strip are controlled by geometric leveling. The actual elevation of such a strip is determined at all points where the design elevation is indicated in the land reclamation project. The actual mark must be at least the design mark and not exceed it by more than 100 mm.

4.12. On non-reclaimed lands, using a template, the height of the roller is controlled, which must be at least the design height and not exceed it by more than 200 mm.

4.13. When laying an aboveground pipeline in an embankment, its width is controlled by a tape measure, the width of the embankment on top should be 1.5 diameters of the pipeline, but not less than 1.5 m and exceed it by no more than 200 mm. The distance from the axis of the pipeline is controlled by a tape measure. The slope of the embankment is controlled by the template.

Reducing the transverse dimensions of the embankment against the design one is allowed by no more than 5%, with the exception of the thickness of the soil layer above the pipeline in sections of convex curves, where a decrease in the backfill layer above the pipeline is not allowed.

4.14. In order to be able to carry out complex work, it is necessary to control the shifting pace of trench development, which must correspond to the shifting pace of insulation and laying work, and in case of factory insulation, the pace of insulating pipe joints and laying the finished pipeline into the trench. Backward trenching is generally not allowed.

4.15. Acceptance of completed earthworks is carried out upon commissioning of the entire pipeline. Upon delivery of completed objects, the construction organization (general contractor) is obliged to transfer to the customer all technical documentation, which should contain:

working drawings with the changes made to them (if any) and a document on the execution of the changes made;

Intermediate acts for hidden work;

drawings of earthworks made according to individual projects in difficult construction conditions;

a list of imperfections that do not interfere with the operation of an earthen structure, indicating the timing of their elimination (in accordance with the agreement and contract between the contractor and the customer);

· a list of permanent benchmarks, geodetic signs and route layout indicators.

4.16. The procedure for acceptance and delivery of completed works, as well as the execution of documentation, must be carried out in accordance with the current rules for the acceptance of works.

4.17. For underground and above-ground laying, the pipeline throughout its entire length must rest on the bottom of the trench or the bed of the embankment.

The correctness of the arrangement of the foundation for the pipeline and its laying (the bottom of the trench along the length, the depth of laying, the support of the pipeline along the entire length, the quality of the filling of the bed from soft soil) must be checked by the construction organization and the customer on the basis of geodetic control before filling the pipeline with soil with the preparation of the corresponding act.

4.18. Particular attention in earthworks is paid to the preparation of the base - a bed for pipelines of large diameters, in particular 1420 mm, the acceptance of which must be carried out using leveling surveys throughout the pipeline.

4.19. Delivery and acceptance of main pipelines, including earthworks, is formalized by special acts.

5. Environmental protection

5.1. The performance of work during the construction of main pipelines should be carried out taking into account the requirements for environmental protection established by federal and republican laws, building codes and rules, including:

¨ Fundamentals of land legislation of the USSR and the Union republics;

¨ Law on the Protection of Atmospheric Air;

¨ Law on the Protection of the Aquatic Environment;

¨ Departmental building codes “Construction of main pipelines. Technology and Organization” (VSN 004-88, Minneftegazstroy. M., 1989);

¨ "Instructions for the performance of construction work in the protected areas of the main pipelines of the Mingazprom" (VSN-51-1-80, M, 1982), as well as these provisions.

5.2. The most significant changes in the natural environment in permafrost areas can occur as a result of a violation of the natural heat exchange of soils with the atmosphere and a sharp change in the water and thermal regime of these soils, which occurs as a result of:

· damage to the moss and vegetation cover along the route and the area adjacent to it;

clearing of forest vegetation;

Disruption of the natural regime of snow deposits.

The combined effect of these factors can significantly increase the adverse effect on the thermal regime of permafrost, especially heavily icy subsiding soils, which can lead to changes in the overall environmental situation over a wide area.

In order to avoid these unpleasant consequences, it is necessary:

¨ earthworks on subsiding soils should be carried out mainly during the period of stable negative air temperatures with the presence of snow cover;

¨ traffic in a snowless period is recommended only within the roadway, the movement of heavy wheeled and caterpillar vehicles outside the road is not allowed;

¨ all construction work on the route is carried out in the shortest possible time;

¨ the preparation of the territory allotted for the construction of pipelines in such areas is recommended to be carried out according to the technology that allows the maximum preservation of the vegetation cover on it;

¨ after completion of work on backfilling the pipeline in certain sections, immediately carry out land reclamation, removal of construction debris and residual materials, without waiting for the commissioning of the entire pipeline;

¨ all damage to the vegetation cover on the construction strip at the end of work should be immediately covered with fast-growing grass that takes root well in these climatic conditions.

5.3. When performing work, any activity leading to the formation of new lakes or the drainage of existing reservoirs, a significant change in the natural drainage of the territory, a change in the hydraulics of streams or the destruction of significant sections of river beds is not recommended.

When performing any work, exclude the possibility of backwater and surface water in areas located outside the right of way. If it is impossible to fulfill this requirement, water passes should be arranged in the soil dumps, including special culverts (siphons).

5.4. When excavating trenches for pipelines, land should be stored in two separate dumps. The upper sod layer is laid in the first dump, and the rest of the soil is laid in the second. After laying the pipeline in the trench, the soil returns to the trench strip in the reverse order with layer-by-layer compaction. Excess soil from the second dump is recommended to be removed to low relief places in such a way as not to disturb the natural drainage regime of the territory.

6. Safety in earthworks

6.1. It is necessary for the technical personnel of construction organizations to ensure that the workers comply with the Safety Rules provided for by the current documents:

6.3. All workers on the track must be familiar with the warning signs used in the production of earthworks.

6.4. Manufacturing enterprises are required to take measures to ensure fire safety and industrial sanitation.

6.5. Places of work, transport and construction machines must be provided with first aid kits with a set of hemostatic, dressings and other means necessary for first aid. Employees must be familiar with the rules for providing first aid.

6.6. Water for drinking and cooking in order to avoid gastrointestinal diseases is recommended to be used on the basis of the conclusion of the local sanitary and epidemiological station only from sources suitable for this purpose. Drinking water must be boiled.

6.7. When performing work in the northern regions of the country in the spring and summer, it is recommended that all workers be provided with protective (Pavlovsky nets, closed overalls) and repellents (dimethyl phthalate, diethyltoluamide, etc.) against mosquitoes, midges, horseflies, midges and instruct on the procedure for using these means . When working in areas where the encephalitis tick is spread, all workers must be given anti-encephalitis vaccinations.

6.8. In winter, special attention should be paid to the implementation of measures to prevent frostbite, including the creation of heating points. Workers should be trained in first aid for frostbite.

MINISTRY
CONSTRUCTION AND HOUSING AND UTILITIES
FARMS OF THE RUSSIAN FEDERATION
(MINSTROY OF RUSSIA)

ORDER

On approval of SP 45.13330.2017
"SNiP 3.02.01-87 Earthworks, foundations and foundations"

In accordance with the Rules for the development, approval, publication, amendment and cancellation of sets of rules approved by Decree of the Government of the Russian Federation dated July 1, 2016 No. of the Russian Federation dated November 18, 2013 No. 1038, paragraph 96 of the Plan for the development and approval of codes of practice and updating previously approved building codes and regulations, codes of practice for 2016 and the planning period until 2017, approved by order of the Ministry of Construction and Housing and Communal Services economy of the Russian Federation dated March 3, 2016 No. 128 / pr, I order:

1. Approve and put into effect 6 months from the date of issuance of this order the attached SP 45.13330.2017 "SNiP 3.02.01-87 Earthworks, bases and foundations".

2. Since the entry into force of SP 45.13330.2017 "SNiP 3.02.01-87 Earthworks, foundations and foundations" to recognize as not applicable SP 45.13330.2012 "SNiP 3.02.01-87 Earthworks, foundations and foundations", approved by order Ministry of Regional Development of the Russian Federation dated December 29, 2011 No. 635/2, with the exception of paragraphs of SP 45.13330.2012 "SNiP 3.02.01-87 Earthworks, foundations and foundations" included in the List of national standards and codes of rules (parts of such standards and sets of rules), as a result of which, on a mandatory basis, compliance with the requirements of the Federal Law "Technical Regulations on the Safety of Buildings and Structures", approved by Decree of the Government of the Russian Federation of December 26, 2014 No. 1521 (hereinafter referred to as the List), is ensured until the relevant changes are made to the List.

3. The Department of Urban Development and Architecture, within 15 days from the date of issue of the order, send the approved SP 45.13330.2017 "SNiP 3.02.01-87 Earthworks, bases and foundations" for registration to the national body of the Russian Federation for standardization.

4. The Department of Urban Development and Architecture shall ensure the publication on the official website of the Ministry of Construction of Russia in the information and telecommunications network "Internet" of the text approved by SP 45.13330.2017 "SNiP 3.02.01-87 Earthworks, bases and foundations" in electronic digital form within 10 days from the date of registration of the set of rules by the national body of the Russian Federation for standardization.

5. To impose control over the execution of this order on the Deputy Minister of Construction and Housing and Communal Services of the Russian Federation Kh.D. Mavliyarova.

MINISTRY OF CONSTRUCTION
AND HOUSING AND UTILITIES
RUSSIAN FEDERATION

SET OF RULES

SP 45.13330.2017

EARTH STRUCTURES,
GROUNDS AND FOUNDATIONS

Updated edition
SNiP 3.02.01-87

Moscow 2017

Foreword

1 PERFORMERS - JSC "Research Center "Construction" - NIIOSP im. N.M. Gersevanova

2 INTRODUCED by the Technical Committee for Standardization TC 465 "Construction"

3 PREPARED for approval by the Department of Architecture, Construction and Urban Planning Policy of the Ministry of Construction, Housing and Communal Services of the Russian Federation (Minstroy of Russia)

4 APPROVED AND PUT INTO EFFECT by Order of the Ministry of Construction, Housing and Communal Services of the Russian Federation dated February 27, 2017 No. 125/pr and entered into force on August 28, 2017.

5 REGISTERED by the Federal Agency for Technical Regulation and Metrology (Rosstandart). Revision of SP 45.13330.2012 "SNiP 3.02.01-87 Earthworks, bases and foundations"

In case of revision (replacement) or cancellation of this set of rules, the corresponding notice will be published in the prescribed manner. Relevant information, notification and texts are also posted in the public information system - on the official website of the developer (Ministry of Construction of Russia) on the Internet

Introduction

This set of rules contains instructions for the production and conformity assessment of earthworks, the construction of foundations and foundations in the construction of new buildings and structures, reconstruction. This set of rules was developed as a development of SP 22.13330 and SP 24.13330.

The revision of this set of rules was carried out by NIIOSP im. N.M. Gersevanova - Institute of JSC "Research Center "Construction" (candidate of technical sciences I.V. Kolybin, cand. tech. Sciences O.A. Shulyatiev- theme leaders; doctor of tech. Sciences: B.V. Bakholdin, IN AND. Krutov, IN AND. Sheinin; cand. tech. Sciences: A.M. Dzagov, F.F. Zekhniev, M.N. Ibragimov, VC. Kogai, V.N. Korolkov, A.G. Alekseev, S.A. Rytov, A.V. Shaposhnikov, P.I. Yastrebov; engineers: A.B. Meshchansky, O.A. Mozgacheva).

SET OF RULES

EARTH STRUCTURES, BASES AND FOUNDATIONS

Earthworks, Grounds and Footings

4.9 Acceptance of earthworks, bases and foundations with the drawing up of certificates of survey of hidden works should be carried out, guided by Appendix B. If necessary, it is allowed to indicate in the project other elements that are subject to intermediate acceptance with the drawing up of certificates of survey of hidden works.

4.10 In projects, it is allowed, with appropriate justification, to establish methods of work and technical solutions, maximum deviations, volumes and methods of control that differ from those provided for by the project by this set of rules.

4.11 The need for monitoring, its scope and methodology are established in accordance with SP 22.13330.

4.12 Earthworks, foundations and foundations consistently include the following steps:

a) preparatory;

b) pilot production (if necessary);

c) production of basic works;

d) quality control;

e) acceptance of work.

4.13 Before starting the construction of foundations, a demolition should be carried out to fix the axes of the building under construction.

5 Dewatering, organization of surface runoff, drainage and drainage

5.1 The rules of this section apply to the performance of works on artificial lowering of the groundwater level (hereinafter referred to as dewatering) at newly constructed or reconstructed facilities, as well as on the removal of surface water from the construction site.

When choosing a method of dewatering, one should take into account the natural environment, the size of the drained area, the methods of construction work in and near the pit, their duration, the impact on nearby buildings and utilities, and other local construction conditions.

5.2 To protect pits and trenches from groundwater, various methods are used, which include borehole water intake, wellpoint method, drainage, beam water intake and open drainage.

5.3 Open (connected to the atmosphere) wells, depending on the task and engineering and geological conditions of the construction site, can be water intake (gravitational and vacuum), self-flowing, absorbing, unloading (to reduce the piezometric pressure in the soil mass), through (when draining water into underground mine).

Open gravity water wells can be effectively used in permeable soils with a filtration coefficient of at least 2 m/day with a required drawdown depth of more than 4 m. Basically, such wells are equipped with submersible electric pumps operating under the bay.

In low-permeability soils (clayed or silty sands) with a filtration coefficient of 0.2 to 2 m/day, vacuum water wells are used, in the cavity of which a vacuum develops with the help of pumping units of wellpoints for vacuum dewatering, which ensures an increase in the water-holding capacity of the wells. Typically, one such unit can serve no more than six wells.

5.4 The wellpoint method, depending on the parameters of the drained soils, the required depth of lowering and the design features of the equipment, is divided into:

On the wellpoint method of gravitational dewatering, used in permeable soils with a filtration coefficient from 2 to 50 m / day, in non-layered soils with a decrease in one step from 4 to 5 m (larger value in less permeable soils);

Wellpoint method of vacuum dewatering, used in low-permeability soils with a filtration coefficient from 2 to 0.2 m / day with a decrease in one step from 5 to 7 m; if necessary, the method with less efficiency can be applied in soils with a filtration coefficient of not more than 5 m/day;

Wellpoint ejector method of dewatering, used in low-permeability soils with a filtration coefficient from 2 to 0.2 m / day at a depth of lowering the groundwater level from 10 to 12 m, and with a certain justification - no more than 20 m.

5.5 Drainages for construction purposes can be linear or reservoir with the inclusion of the last linear type drainage in the design.

Linear drainages carry out drainage of soils by withdrawing groundwater using perforated pipes with sand and gravel (crushed stone) sprinkling with the withdrawal of selected waters to sumps equipped with submersible pumps. The effective depth of drainage by linear drainage is from 4 to 5 m.

Linear drainage can be arranged inside the pit, at the base of the slopes of earthworks, in the areas surrounding the construction site.

Reservoir drainages are provided for the withdrawal of groundwater during the construction period from the entire area of the pit. This type of drainage is carried out when groundwater is withdrawn in soils with a filtration coefficient of less than 2 m / day, as well as in cases of flooded fractured rocky base.

When groundwater is withdrawn from silty or clayey soils, the reservoir drainage design provides for two layers: the lower one is made of coarse-grained sand with a thickness of 150 to 200 mm and the upper one is made of gravel or crushed stone with a thickness of 200 to 250 mm. If in the future it is planned to operate the reservoir drainage as a permanent structure, then the thickness of its layers should be increased.

When sampling groundwater from rocky soils, in the cracks of which there is no sandy-argillaceous filler, reservoir drainage can consist of one gravel (crushed stone) layer.

The removal of groundwater taken by reservoir drainage is carried out into a linear drainage system, the sand and gravel dressing of which is mated with the reservoir drainage body.

5.6 Open drainage is used for temporary drainage of the surface layer of soil in pits and trenches. Shallow drainage ditches can be both open and filled with filter material (crushed stone, gravel). Groundwater captured by grooves is diverted to sumps equipped with submersible pumps.

5.7 Prior to the start of work on dewatering, it is necessary to examine the technical condition of buildings and structures located in the zone of influence of the work, as well as clarify the location of existing underground utilities, assess the impact on them of lowering the groundwater level (GWL) and, if necessary, provide for protective measures.

5.8 Dewatering wells equipped with submersible pumps are the most common types of dewatering systems and can be used in a wide variety of hydrogeological conditions. The depths of the wells are determined depending on the depth and thickness of the aquifer, the filtration characteristics of the rocks, and the required level of groundwater level decrease.

5.9 Drilling of dewatering wells, depending on the hydrogeological conditions, can be carried out with direct or reverse flushing or with a shock-rope method. Drilling wells with clay flushing is not allowed.

5.10 Installation of filter columns in dewatering wells is carried out in compliance with the following requirements:

a) before installing the filter column in the percussion-rope drilling method, the bottom of the well should be thoroughly cleaned by pouring clean water into it and gelling until completely clarified; during rotary drilling with direct and reverse flushing, the well is pumped or washed with a mud pump;

b) when installing the filter, it is necessary to make sure of the strength and tightness of the connections of its lowered links, the presence of guide lights and a plug of the column sump on the column;

c) when drilling wells, it is necessary to take samples to clarify the boundaries of aquifers and the granulometric composition of soils.

5.11 To increase the water-holding capacity of wells and wellpoints in water-saturated soils with a filtration coefficient of less than 5 m/day, as well as in coarse-grained or fractured soils with fine aggregate, sand and gravel (or crushed stone) backfilling with a particle size of 0.5 up to 5 mm.

When taking water from fractured soils (for example, limestone), backfilling can be omitted.

5.12 The backfilling of filters should be carried out evenly in layers no more than 30 times the backfill thickness. After each next rise of the pipe above its lower edge, a layer of backfill must remain at least 0.5 m high.

5.13 Immediately after installing the filter column and the sand and gravel pack, it is necessary to thoroughly pump the well with an airlift. The well can be put into operation after it has been continuously pumped by an airlift for 1 day.

5.14 The pump should be lowered into the well to such a depth that, with a fully open valve on the injection pipeline, the suction port of the pump is below the dynamic air pressure limiter. When the dynamic level drops below the suction port, the pump should be lowered to a greater depth or, if this is not possible, the pump performance should be adjusted with a valve.

5.15 Installation of pumps in wells should be carried out after checking the wells for patency along the entire height of its wellbore with a template, the diameter of which exceeds the diameter of the pump.

5.16 Before lowering the submersible pump into the well, it is necessary to measure the insulation resistance of the motor windings, which must be at least 0.5 MΩ. The pump can be turned on no earlier than 1.5 hours after the descent. In this case, the resistance of the motor windings must be at least 0.5 MΩ.

5.17 All dewatering wells should be equipped with gate valves, which will allow regulating the flow rate of the well and the system as a whole during the pumping process. After the construction of the well, it is necessary to carry out a test pumping.

5.18 Considering that the dewatering system must operate continuously, it is necessary to ensure its power supply redundancy by supplying power from two substations with supply from different sources or receiving electricity from one substation, but with two independent high-side inputs, two independent transformers and two power cables with bottom side.

5.19 The power supply system of pumping units should have automatic protection against short circuit currents, overload, sudden power outage and overheating of the electric motor. Water-lowering systems should be equipped with devices for automatically shutting down any unit when the water level in the water intake drops below the permissible level.

5.20 The filter part of vacuum wells and wellpoints of vacuum installations should be located at least 3 m below ground level to prevent air leakage.

5.21 Measures should be taken to prevent damage or clogging of dewatering and observation wells by foreign objects. The heads of the latter must be equipped with lids with a locking device.

5.22 After the installation of a dewatering well, it should be checked for water absorption.

5.23 Before the general start-up of the system, it is necessary to start-up each well separately. The start-up of the entire dewatering system is formalized by an act signed by the responsible persons.

5.24 The dewatering system should additionally include standby wells (at least one), as well as standby open drainage pumping units (at least one), the number of which, depending on the service life, should be equal to the total estimated number of units:

Not more than 1 year - 10%;

Not more than 2 years - 15%;

Not more than 3 years - 20%;

More than 3 years - 25%.

5.25 During the operation of wellpoint systems, air infiltration into the suction system of the unit should be excluded.

In the process of hydraulic immersion of wellpoints, it is necessary to control the presence of a constant outflow from the wells, and also to exclude the installation of the wellpoint filter element in a low-permeable layer (s) of soil. In the absence of a spout or a sharp change in the flow rate of water coming from the well, it is necessary to check the throughput of the filter in bulk, if necessary, remove the wellpoint and establish whether the filter outlet is free, whether it has been clogged. It is also possible that the filter is installed in a highly permeable layer of soil, which absorbs the entire flow rate of water entering the wellpoint. In this case, when immersing the wellpoint, it is necessary to organize a joint supply of water and air.

In groundwater captured by wellpoints, soil particles should not be detected, and sanding should be excluded.

5.26 Extraction of wellpoints from the ground during their dismantling is carried out by means of a special truck crane with a thrust stand, a drilling rig or using jacks.

5.27 In case of wind force of 6 points or more, as well as in hail, rain and at night on an unlit site, installation of wellpoints is prohibited.

5.28 During installation and operation of the wellpoint system, incoming and operational control should be carried out.

5.29 After the dewatering system is put into operation, pumping should be carried out continuously.

5.30 The rate of decrease in WLL during dewatering should correspond to the rate of earthworks provided for in the PPR when opening pits or trenches. With a significant advance in the level decrease in relation to the excavation schedule, an unjustified power reserve of the dewatering system arises.

5.31 During the performance of dewatering works, the reduced WLL should be ahead of the level of development of the pit by a height of one tier, developed by earthmoving equipment, i.e. by 2.5 - 3 m. This condition will ensure the execution of earthworks "dry".

5.32 Control over the efficiency of the dewatering system should be carried out by regular measurements of the WLL in observation wells. It is mandatory to install water meters that control the flow rate of the system. The measurement results must be recorded in a special log. The initial measurement of WLL in observation wells should be carried out before the commissioning of the dewatering system.

5.33 Pumping units installed in reserve wells, as well as reserve pumps of open installations, should be periodically put into operation in order to maintain them in working order.

5.34 Measurements of the reduced WLL during drawdown should be carried out in all aquifers affected by the work of the drawdown system. Periodically, at complex facilities, the chemical composition of the pumped waters and their temperature should be determined. Observations of the PWL should be carried out 1 time in 10 days.

5.35 All data on the operation of dewatering plants should be displayed in the log: the results of WLL measurements in observation wells, system flow rates, stop and start times during the shift, pump replacement, slope condition, appearance of griffins.

5.36 Upon termination of the operation of a system consisting of dewatering wells, acts should be drawn up for the completion of well liquidation.

5.37 When operating dewatering systems in winter, pumping equipment and communications should be insulated, and it should be possible to empty them during breaks in operation.

5.38 All permanent water-reducing and drainage devices used during the construction period, when put into permanent operation, must comply with the requirements of the project.

5.39 Dismantling of dewatering installations should be started from the lower tier after completion of backfilling of pits and trenches or immediately before their flooding.

5.40 In the zone of influence of the dewatering, observations should be regularly made of precipitation and the intensity of its growth for buildings and communications located in the immediate vicinity.

5.41 When carrying out dewatering works, measures should be taken to prevent decompaction of soils, as well as violation of the stability of the slopes of the pit and the foundations of adjacent structures.

5.42 Water flowing into the pit from the overlying layers and not captured by the dewatering system should be diverted by drainage ditches to sumps and removed from them using open drainage pumps.

5.43 Monitoring of the state of the bottom and slopes of an open pit during dewatering should be carried out daily. When slopes sink, suffusion, griffins appear at the bottom of the pit, protective measures should be taken immediately: loosening the crushed stone layer on the slopes at groundwater outlets, loading with a layer of crushed stone, putting unloading wells into operation, etc.

5.44 When the slope of the pit crosses impervious soils lying under the aquifer, a berm with a ditch for water drainage should be made on the roof of the aquiclude (if the project does not provide for drainage at this level).

5.45 When draining groundwater and surface water, flooding of structures, the formation of landslides, soil erosion, and waterlogging of the area should be prevented.

5.46 Before the start of earthworks, it is necessary to ensure the drainage of surface and groundwater using temporary or permanent devices, without violating the safety of existing structures.

5.47 When diverting surface and groundwater, it is necessary:

a) on the upper side of the recesses to intercept the flow of surface waters, use cavaliers and reserves arranged by a continuous contour, as well as permanent catchment and drainage structures or temporary ditches and embankments; ditches, if necessary, may have protective fastenings against erosion or filtration leaks;

b) cavaliers from the downstream side of the recesses should be poured with a break, mainly in low places, but at least every 50 m; the width of the gaps along the bottom must be at least 3 m;

c) lay the soil from upland and drainage ditches arranged on slopes in the form of a prism along the ditches from their downstream side;

d) when the upland and drainage ditches are located in the immediate vicinity of the linear recesses between the recess and the ditch, perform a banquet with a slope of its surface of 0.02 - 0.04 towards the upland ditch.

5.48 When pumping water from a pit developed by an underwater method, the rate of lowering the water level in it, in order to avoid disturbing the stability of the bottom and slopes, must correspond to the rate of lowering the level of groundwater outside it.

5.49 When arranging drainages, earthworks should be started from discharge areas moving towards higher elevations, and the laying of pipes and filter materials should be started from watershed areas moving towards the discharge or pumping unit (permanent or temporary) to prevent the passage of unclarified water through the drainage.

5.50 When arranging reservoir drainages, violations in the mating of the crushed stone layer of the bed with the crushed stone sprinkling of pipes are unacceptable.

5.51 Laying of drainage pipes, installation of manholes and installation of equipment for drainage pumping stations must be carried out in compliance with the requirements of SP 81.13330 and SP 75.13330.

5.52 The list of as-built documentation for construction dewatering using wells should include:

a) the act of commissioning the water reduction system;

b) executive layout of wells;

c) executive schemes of well designs indicating the actual geological columns;

d) an act on the liquidation of wells upon completion of work;

e) certificates for the materials and products used.

5.53 When performing work on dewatering, organization of surface runoff and drainage, the composition of controlled indicators, limit deviations, scope and methods of control must comply with the table in Appendix I.

6 Vertical planning, development of excavations, preparation of the territory for building with hydraulic fill

6.1 Grading, excavation

6.1.1 The dimensions of the excavations adopted in the project should ensure the placement of structures and the mechanized performance of work on driving piles, installation of foundations, insulation, dewatering and drainage and other work performed in the excavation, as well as the possibility of moving people in the bosom in accordance with 6.1.2 . The dimensions of the recesses along the bottom in kind must be at least those established by the project.

6.1.2 If it is necessary to move people in the sinus, the distance between the surface of the slope and the side surface of the structure being erected in the excavation (except for the artificial foundations of pipelines, collectors, etc.) must be at least 0.6 m in the clear.

6.1.3 The minimum width of trenches in the project should be taken as the largest of the values that meet the following requirements:

Under strip foundations and other underground structures - should include the width of the structure, taking into account the formwork, the thickness of the insulation and fasteners, with an addition of 0.2 m on each side;

Pipelines, except for main ones, with slopes of 1: 0.5 and steeper - according to the table;

Pipelines, except for main pipelines, with slopes of 1:0.5 - not less than the outer diameter of the pipe with the addition of 0.5 m when laying in separate pipes and 0.3 m when laying with lashes;

Pipelines in sections of curved inserts - at least twice the width of the trench in straight sections;

Arrangement of artificial bases for pipelines, except for soil bedding, collectors and underground channels - not less than the width of the base with an addition of 0.2 m on each side;

Developed by single-bucket excavators - not less than the width of the cutting edge of the bucket with the addition of 0.15 m in sand and sandy loam, 0.1 m in clay soils, 0.4 m in loosened rocky and frozen soils.

Way of laying pipelines	Trench width, m, excluding fasteners for butt joints of pipelines
Way of laying pipelines	welded	bell-shaped	coupling, flange, seam for all pipes and socket for ceramic pipes
1 In lashes or separate sections with the outer diameter of the pipesD, m:
up to 0.7 per key.	D+ 0.3, but not less than 0.7
St. 0.7	1,5D
2 The same, in areas developed by trench excavators for pipelines with a diameter of not more than 219 mm, laid without lowering people into trenches (narrow trench method)	D+ 0,2
3 The same, in sections of the pipeline loaded with reinforced concrete weights or anchor devices	2,2D
4 The same, in sections of the pipeline loaded with non-woven synthetic materials	1,5 D
5 Separate pipes with outside pipe diameterD, m, incl.:
up to 0.5	D + 0,5	D + 0,6	D + 0,8
from 0.5 to 1.6	D + 0,8	D + 1,0	D + 1,2
» 1.6 » 3.5	D + 1,4	D + 1,4	D + 1,4
Notes 1 The width of trenches for pipelines with a diameter of more than 3.5 m is set in the project based on the technology of foundation, installation, insulation and sealing of joints. 2 When laying several pipelines in parallel in one trench, the distances from the outermost pipes to the walls of the trenches are determined by the requirements of this table, and the distances between the pipes are established by the project.

6.1.4 The dimensions of the pits for sealing the joints of pipelines must not be less than those indicated in Table 6.2.

Table 6.2

Pipe	Butt joint	sealant	Conditional passage of the pipeline, mm	Pit size, m
Pipe	Butt joint	sealant	Conditional passage of the pipeline, mm	Length	Width	Depth
Steel	Welded		For all diameters		D * + 1,2
Cast iron	Bell-shaped	Rubber cuff	Up to 300 incl.		D + 0,2
		hemp strand	Up to 300 incl.	0,55	D + 0,5
		hemp strand	St. 300		D + 0,7
		Sealants	Up to 300 incl.		D + 0,5
		Sealants	St. 300		D + 0,7
Chrysotile cement	Coupling type CAM	Shaped rubber ring	Up to 300 incl.		D + 0,2
	Coupling type CAM	Shaped rubber ring	St. 300		D + 0,5
	Cast iron flange coupling	Rubber o-ring and KChM type	Up to 300 incl.		D + 0,5
	Cast iron flange coupling	Rubber o-ring and KChM type	St. 300		D + 0,7
	Any for non-pressure pipes	Any	Up to 400 incl.		D + 0,5
Concrete and reinforced concrete	Socket, coupling and with concrete belt	Rubber o-ring	Up to 600 incl.		D + 0,5
Concrete and reinforced concrete	Socket, coupling and with concrete belt	Rubber o-ring	600 to 3500		D + 0,5
Polymer	All types butt joints		For all diameters		D + 0,5
Ceramic	Bell-shaped	Asphalt bitumen, sealant, etc.	Same		D + 0,6
________ * D- outer diameter of the pipeline at the joint. Note - For other joint designs and pipeline diameters, the dimensions of the pits should be set in the project.

6.1.5 In pits, trenches and profile excavations, the development of eluvial soils that change their properties under the influence of atmospheric influences should be carried out, leaving a protective layer, the value of which and the permissible duration of contact of the exposed base with the atmosphere are established by the project, but not less than 0.2 m. The protective layer is removed immediately before the start of the construction of the structure.

6.1.6 Excavations in soils, except for boulders, rocks and those specified in 6.1.5, should be developed, as a rule, up to the design level while maintaining the natural composition of the base soils. It is allowed to develop excavations in two stages: rough - with the deviations given in clauses 1 - 4 of Table 6.3, and final (immediately before the erection of the structure) - with the deviations given in pos. 5 of the same table.

Technical requirement	Limit deviation	Control (method and scope)
1 Deviations of the bottom marks of the excavations from the design ones (except for excavations in boulder, rocky and permafrost soils) during rough development:		Measuring, measurement points are set randomly; the number of measurements per received area must be at least:
a) single-bucket excavators equipped with buckets with teeth	For mechanically driven excavators by type of working equipment:
	dragline +25 cm
	direct digging +10 cm
	backhoe +15 cm
	For excavators with hydraulic drive +10 cm
b) single-bucket excavators equipped with grading buckets, cleaning equipment and other special equipment for grading work, excavators-planners	5 cm
c) bulldozers	10 cm
d) trench excavators	10 cm
e) scrapers	10 cm
2 Deviations of the elevations of the bottom of the excavations from the design ones during rough development in rocky and permafrost soils, except for planning excavations:		Measuring, with the number of measurements on the leased area at least 20 in the highest places, established by visual inspection
a) shortfalls	Not allowed
b) busts		Same
3 The same, planning recesses:
a) shortfalls	10 cm
b) busts	20 cm
4 The same, without loosening boulder soils:
a) shortfalls	Not allowed
b) busts	Not more than the value of the maximum diameter of boulders (blocks) contained in the soil in an amount of more than 15% by volume, but not more than 0.4 m
5 Deviations of the marks of the bottom of the excavations in the places of foundations and laying of structures during the final development or after completion of shortfalls and replenishment of busts	±5 cm	Measuring, at the corners and center of the pit at the intersections of the axes of the building, at the places of changes in elevations, turns and junctions of trenches, the location of wells, but not less than 50 m and not less than 10 measurements per received area
6 Type and characteristics of the exposed soil of natural bases for foundations and earthworks	Must match the project. It is not allowed to wash out, soften, loosen or freeze the top layer of the base soil with a thickness of more than 3 cm	Technical inspection of the entire surface of the base
7 Deviations from the design longitudinal slope of the bottom of trenches for free-flow pipelines, drainage ditches and other excavations with slopes	Must not exceed ±0.0005	Measuring, in places of turns, junctions, location of wells, etc., but not less than 50 m
8 Deviations of the slope of the planned surface from the design one, except for irrigated lands	Should not exceed ±0.001 in the absence of closed depressions
9 Deviations of the levels of the planned surface from the design ones, except for irrigated lands:	Should not exceed:
a) in non-rocky soils	±5 cm	Visual (monitoring of precipitation runoff) or measuring, on a grid of 50 × 50 m
b) in rocky soils	+10 to -20 cm	Measuring, on a grid of 50 × 50 m

6.1.7 Finalization of shortfalls to the design level should be carried out while maintaining the natural composition of the soil.

6.1.8 Replenishment of bulkheads in places where foundations are constructed and pipelines laid must be carried out with local soil with compaction to the density of soil of natural foundation or low-compressibility soil (deformation modulus of at least 20 MPa), taking into account the table of Appendix M. In subsiding soils of type II, the use of drainage soil.

6.1.9 The method of restoring foundations damaged as a result of freezing, flooding, as well as busting, must be agreed with the design organization.

6.1.10 The greatest steepness of slopes of trenches, pits and other temporary excavations, arranged without fastening in soils that are above the groundwater level (taking into account the capillary rise of water according to 6.1.11), including in soils drained by artificial dewatering, should be take in accordance with the requirements ensuring labor safety in construction.

With a slope height of more than 5 m in homogeneous soils, their steepness can be taken according to the schedules of the application. The steepness of the slopes should ensure the safety of work in construction. The steepness of the slopes of excavations developed in rocky soils using blasting must be established in the project.

6.1.11 If there is groundwater during the period of work within the excavations or near their bottom, not only soils located below the groundwater level, but also soils located above this level by the amount of capillary rise should be considered wet, which should be taken:

0.3 m - for large, medium size and fine sands;

0.5 m - for silty sands and sandy loams;

1.0 m - for loams and clays.

6.1.12 The steepness of the slopes of underwater and flooded coastal trenches, as well as trenches developed in swamps, should be taken in accordance with the requirements of SP 86.13330.

6.1.13 The design shall establish the steepness of the slopes of soil pits, reserves and permanent dumps after the completion of earthworks, depending on the directions of reclamation and methods of fixing the surface of the slopes.

6.1.14 The maximum depth of excavations with vertical loose walls should be taken in accordance with the requirements that ensure labor safety in construction.

6.1.15 The greatest height of the vertical walls of excavations in frozen soils, except for loosely frozen soils, at an average daily air temperature below minus 2 °C, may be increased by the depth of soil freezing, but not more than 2 m.

6.1.16 The project shall establish the need for temporary fastening of the vertical walls of trenches and pits, depending on the depth of excavation, the type and condition of the soil, hydrogeological conditions, the magnitude and nature of temporary loads on the edge and other local conditions.

6.1.17 The number and size of ledges and local recesses within the excavation should be minimal and ensure mechanized cleaning of the base and manufacturability of the construction of the structure. The ratio of the height of the ledge to its base is established by the project, but should be at least: 1:2 - in clay soils, 1:3 - in sandy soils.

6.1.18 If it is necessary to develop excavations in the immediate vicinity and below the sole of the foundations of existing buildings and structures, the project should provide for technical solutions to ensure their safety.

6.1.19 The places of overlapping of developed excavations or backfilled embankments on the security zones of existing underground and air communications, as well as underground structures, must be indicated in the project, indicating the size of the security zone, established in accordance with the instructions.

In case of detection of communications, underground structures or signs designating them that are not specified in the project, earthworks should be suspended, representatives of the customer, designer and organizations operating the discovered communications should be called to the work site, and measures should be taken to protect the discovered underground devices from damage.

6.1.20 The development of pits, trenches, excavations, the construction of embankments and the opening of underground utilities within the security zones are allowed with the written permission of the operating organizations and the conclusion of a certified organization to assess the impact of construction work on the technical condition of communications.

6.2.1.3 If the soil contains more than 0.5% of the volume of inclusions oversized for soil pumps (boulders, stones, bogs), it is prohibited to use suction dredgers and installations with soil pumps without devices for preliminary selection of such inclusions. Oversized should be considered inclusions with an average transverse size of more than 0.8 of the minimum flow area of the pump.

6.2.1.4 When laying pressure slurry pipelines, the turning radii must be at least 3-6 pipe diameters. At turns with an angle of more than 30°, slurry pipelines and water conduits must be fixed. All pressure slurry pipelines must be tested to the maximum working pressure. The correct laying and reliability in the operation of pipelines is formalized by an act drawn up based on the results of their operation within 24 hours of working time.

6.2.1.5 The parameters for the development of cuts and quarries with floating suction dredgers and maximum deviations from the marks and dimensions established in the PPR should be taken from Table 6.5.

RUSSIAN JOINT STOCK COMPANY
GAZPROM SYSTEM OF REGULATORY DOCUMENTS IN CONSTRUCTION CODE OF CONSTRUCTION RULES
MAIN GAS PIPELINES CODE OF RULES FOR CONSTRUCTION
LINEAR PART OF GAS PIPELINES

EARTHWORKS

SP 104-34-96

Approved by RAO Gazprom

(Order dated September 11, 1996 No. 44)

Set of rules

Code of Rules for the Construction of Main Gas Pipelines

C ode of the regulations on construction of trunk gas pipelines

Date of introduction 1.10.1996

Earthworks production

Developed by the Highly Reliable Pipeline Transport Association, RAO Gazprom, JSC Rosneftegazstroy, JSC VNIIST, JSC NGS-Orgproektekonomika. Agreed with the Ministry of Construction of the Russian Federation by letter No. 13/567 of December 7, 1995.

Under the general editorship

acad. B.E. Patona, Ph.D. tech. Sciences V.A. Dinkov. prof. O.M. Ivantsova

INTRODUCTION

In order to ensure year-round construction and the possibility of flow-mechanized performance of the entire complex of construction and installation works, especially in difficult conditions, compliance with the design parameters of pipeline elements during laying and the requirements for the reliability of their operation during operation, modern progressive methods of organizing and technologies for the production of works, quality control and acceptance of earthworks in various climatic and soil zones. The Code of Rules summarizes the results of research and design development, as well as best practices in earthworks, accumulated by construction organizations in domestic and foreign practice in the construction of linear facilities. This joint venture proposes new methods for the construction of main pipelines in difficult natural and climatic conditions, reflects methods for developing trenches, constructing embankments, drilling holes and wells for pile supports, backfilling trenches taking into account the design parameters of pipelines, the specifics of drilling and blasting operations, including including the parallel laying of multi-line highways on different sections of the route. This joint venture is intended for specialists in construction and design organizations involved in earthworks during the construction of the linear part of pipelines, as well as in the development of projects for the organization of construction and production of works (POS and PPR).

Terminology

Trench - a recess, usually of considerable length and relatively small width, intended for laying the pipeline being laid. A trench as a temporary earthwork is developed in certain parameters depending on the diameter of the pipeline under construction and can be arranged with slopes or with vertical walls. The dump is usually called the soil laid along the trench during its development by earthmoving machines. Embankments are earthworks intended for laying pipelines when crossing low or difficult terrain, as well as for building a roadbed along them or softening the route profile when planning a construction strip by means of additional soil filling. Excavations are earthworks arranged by cutting the soil while softening the longitudinal profile of the route and laying roads along the pipeline construction strip. Semi-dredging-semi-filling - earthworks, combining the features of cutting and embankment, intended for laying pipelines and roads on steep slopes (mainly transverse slopes). Ditches - structures in the form of linear recesses, usually arranged to drain the construction strip, they are often called drainage or drainage. Ditches that serve to intercept and divert water flowing from the upstream territory and arranged on the uphill side of the earthen structure are called upland. Ditches that serve to drain water and are located along both boundaries of cuts or roads are called ditches. Ditches laid during the construction of pipelines (ground method) in swamps along the boundaries of the ROW and used to store water are called fire ditches. Cavaliers are called embankments, filled out of excess soil formed during the development of recesses, and located along the latter. Reserves are usually called excavations, the soil from which is used for filling adjacent embankments. The reserve is separated from the embankment slope by a protective berm. Quarry - a specially developed excavation for the use of soil when filling embankments and located at a considerable distance from them. Channel - a recess of considerable length and filled with water. Channels are usually arranged during the construction of pipelines in swamps and wetlands and serve as a trench for laying pipelines using the alloy method or as a main channel for a drainage network of a drainage system. The structural elements of the trench are the profile of the trench, the soil dump, the roller above the trench (after it has been backfilled with soil). The structural elements of the embankment are subgrade, ditches, cavaliers and reserves. The trench profile, in turn, has the following characteristic elements: bottom, walls, edges. Embankments have: a base, slopes, a sole and edges of slopes, a ridge. Bed - a layer of loose, usually sandy soil (10-20 cm thick), poured onto the bottom of the trench in rocky and frozen soils to protect the insulating coating from mechanical damage when laying the pipeline in the trench. Powder - a layer of soft (sandy) soil, poured over a pipeline laid in a trench (20 cm thick), before filling it with loosened rocky or frozen soil to the design mark of the earth's surface. The overburden layer of soil is a mineral soft top layer of soil that lies above the continental rocks, which is subject to priority removal (opening) from the construction strip, for the subsequent effective development of rock soil by drilling and blasting. Boreholes - cylindrical cavities in the soil with a diameter of up to 75 mm and a depth of not more than 5 m, formed by drilling rigs for placing explosive charges when loosening solid soils using the drilling and blasting blasthole method (for constructing trenches). Wells - cylindrical cavities in the soil with a diameter of more than 76 mm and a depth of more than 5 m, formed by drilling machines for placing explosive charges in them during drilling and blasting operations, both for loosening the soil and blasting for dumping when arranging shelves in mountainous areas. Integrated sequential method - a method for developing trenches mainly in high-strength permafrost soils for ballasted pipelines with a diameter of 1420 mm, which consists in sequential passage along the trench alignment of several types of rotary trench excavators, or rotary excavators of the same type with different parameters of the working body for constructing a trench of a design profile (up to 3 3m). Technological gap - the distance along the front between the grips of the production of certain types of work of the technological process of constructing a linear part of the main pipeline within the right of way (for example, a technological gap between preparatory and earthworks, between welding and installation and insulation and laying, and during earthworks in rocky soils gap between teams for overburden, drilling, blasting and excavation of trenches in soils loosened by the explosion). Operational quality control of work - a continuous technological process of quality control, carried out in parallel with the implementation of any construction and installation operation or process, is carried out in accordance with the technological maps of operational quality control developed for all types of work on the construction of the linear part of the main pipelines. The technological map of the step-by-step quality control of earthworks reflects the main provisions on the technology and organization of step-by-step control, technological requirements for machines, determines the main processes and operations that are subject to control, controlled indicators that are characteristic of earthworks, the composition and types of control, as well as forms of executive documentation, where the test results are recorded.

1. General Provisions

1.1. The technology of the entire range of earthworks, including the engineering preparation of the construction strip, in order to comply with the required dimensions and profiles of earthworks, as well as regulated tolerances during earthworks, must be carried out in accordance with the Project, developed taking into account the requirements of current regulatory documents: ¨ "Main pipelines" (SNiP III-42-80); ¨ "Organization of construction production" (SNiP 3.01.01-80); ¨ Earthworks. Bases and Foundations” (SNiP 3.02.01-87); ¨ "Norms of Land Acquisition for Main Pipelines" (SN-452-73) Fundamentals of Land Legislation of the USSR and Union Republics; ¨ “Construction of main pipelines. Technology and Organization” (VSN 004-88, Minneftegazstroy, P, 1989); ¨ RF Law on Environmental Protection; ¨ Technical Rules for blasting on the day surface (M., Nedra, 1972); ¨ Instructions on the technology of blasting in frozen pounds near existing steel underground main pipelines (VSN-2-115-79); ¨ This Code of Rules. Detailed development of technology and organizational measures is carried out in the preparation of technological maps and projects for the production of works for specific production processes, taking into account the specifics of the relief and soil conditions of each section of the pipeline route. 1.2. Earthworks should be carried out with the provision of quality requirements and with mandatory operational control of all technological processes. It is recommended that all subdivisions for the production of earthworks be provided with step-by-step quality control cards, which are developed in the development of POS and PPR, schemes for integrated mechanization for the construction of main pipelines by design organizations of the industry. 1.3. Excavation work must be carried out in compliance with the Safety Rules, industrial sanitation and the latest achievements in the field of labor protection. The whole range of earthworks during the construction of pipelines is carried out in accordance with the projects for the organization of construction and work. 1.4. The technology and organization of earthworks should provide for the flow of their production, year-round performance, including on difficult sections of the route, without a significant increase in their labor intensity and cost, while maintaining the specified pace of work. The exception is work on permafrost soils and wetlands of the Far North, where work is recommended to be done only during the period of soil freezing. 1.5. Management and management of labor protection, as well as responsibility for ensuring the conditions for compliance with labor protection requirements in specialized divisions, are recommended to be assigned to managers, chiefs and chief engineers of these organizations. At work sites, the heads of sections (columns), foremen and foremen are responsible for compliance with these requirements. 1.6. Construction machinery and equipment for earthworks must comply with the technical conditions of operation, taking into account the conditions and nature of the work performed; in northern regions with low air temperatures, it is recommended to mainly use machines and equipment in the northern version. 1.7. During the construction of main pipelines, lands provided for temporary use must be brought into line with the requirements of the on-farm land management project of the relevant land users: in the course of excavation, it is not recommended to use techniques and methods that promote flushing, blowing and sinking of soils and soils, the growth of ravines, erosion of sands , the formation of mudflows and landslides, salinization, waterlogging of soils and other forms of loss of fertility; · when draining the right of way by open drainage, discharge of drainage water into sources of water supply for the population, medical water resources, places of recreation and tourism should not be allowed.

2. Production of earthworks. Land reclamation works

2.1. It is recommended to carry out work on the removal and restoration of the layer within the construction strip in accordance with a special land reclamation project. 2.2. The land reclamation project should be developed by design organizations taking into account the specifics of specific sections of the route and be agreed with the land users of these sections. 2.3. Fertile lands are brought into a usable condition, as a rule, in the process of construction work on the pipeline, and if this is not possible, no later than within a year after the completion of the entire complex of works (as agreed with the land user). All work must be completed within the period of land acquisition for construction. 2.4. In the land reclamation project, in accordance with the conditions for the provision of land plots for use and taking into account local natural and climatic features, the following should be determined: ¨ the boundaries of the lands along the pipeline route in which reclamation is necessary; ¨ the thickness of the removed fertile soil layer for each site subject to reclamation;

Rice. Schematic diagram of the right-of-way during the construction of main pipelines

A - the minimum width of the strip in which the fertile soil layer is removed (the width of the trench along the top plus 0.5 m in each direction)

¨ the width of the reclamation zone within the ROW; ¨ the location of the dump for temporary storage of the removed fertile soil layer; ¨ methods of applying a fertile soil layer and restoring its fertility; ¨ permissible excess of the applied fertile soil layer above the level of undisturbed lands; ¨ methods of compaction of loosened mineral soil and fertile layer after backfilling of the pipeline. 2.5. Work on the removal and application of the fertile soil layer (technical reclamation) is carried out by the construction organization; restoration of soil fertility (biological reclamation, including fertilization, sowing of grasses, restoration of moss cover in the northern regions, plowing of fertile soils and other agricultural work) is carried out by land users at the expense of funds provided for by the estimate for reclamation included in the summary construction estimate. 2.6. When developing and agreeing on a land reclamation project for a pipeline laid parallel to an existing gas pipeline, one should take into account its actual position in the plan, the actual depth of occurrence and technical condition, and based on these data, develop design solutions that ensure the safety of the existing pipeline and the safety of work in accordance with "Instructions for the performance of work in the protected zone of main pipelines" and the current safety regulations. 2.7. When laying a pipeline parallel to an existing pipeline, it should be taken into account that the operating organization, before starting work, must mark the location of the axis of the existing pipeline on the ground, identify and mark dangerous places with special warning signs (areas of insufficient deepening and sections of the pipeline that are in poor condition). During the period of work near the existing pipelines or at the intersection with them, the presence of representatives of the operating organization is necessary. As-built documentation for covert work should be drawn up according to the forms given in VSN 012-88, part II. 2.8. The technology of work on the technical reclamation of disturbed lands during the construction of main pipelines consists in removing the fertile soil layer before the start of construction work, transporting it to a temporary storage site and applying it to the restored lands upon completion of construction work. 2.9. In the warm season, the removal of the fertile soil layer and its transfer to the dump should be carried out with a rotary reclamator of the ETR 254-05 type, as well as bulldozers (D-493A, D-694, D-385A, D-522, DZ-27S types) longitudinally transverse passages with a layer thickness of up to 20 cm and transverse - with a layer thickness of more than 20 cm. When the thickness of the fertile layer is up to 10 - 15 cm, it is recommended to use motor graders to remove and move it to the dump. 2.10. The removal of the fertile soil layer should be carried out for the entire design thickness of the reclamation layer, if possible, in one pass or in layers in several passes. In all cases, mixing of the fertile soil layer with mineral soil should not be allowed. Excess mineral soil formed as a result of the displacement of the volume when laying the pipeline into the trench, in accordance with the project, can be evenly distributed and planned on the strip of the removed fertile soil layer (before applying the latter) or taken out of the construction strip to specially designated places. Removal of excess mineral soil is carried out according to two schemes: 1. After backfilling the trench, the mineral soil is evenly distributed by a bulldozer or motor grader over the strip to be recultivated, then after its compaction, the soil is cut with scrapers (D-357M, D-511C, etc.) to the required depth in such a way as to ensure an allowable excess of the level of applied fertile soil layer above the surface of undisturbed lands. The soil is transported by scrapers to the places specially indicated in the project; 2. Mineral soil after leveling and compaction is cut and moved by a bulldozer along the strip and placed in order to increase the efficiency of its loading onto transport in special collars up to 1.5 - 2.0 m high with a volume of up to 150 - 200 m 4225, equipped with a bucket with a straight shovel or grab), or single-bucket front-end loaders (type TO-10, TO-28, TO-18) are loaded into dump trucks and taken out of the construction strip to places specially specified in the project. The first scheme is recommended for a distance of soil removal up to 0.5 km, the second - more than 0.5 km. 2.11. If, at the request of land users, the project also provides for the removal of the fertile soil layer outside the construction strip to special temporary dumps (for example, on especially valuable lands), then its removal and transportation to a distance of up to 0.5 km should be carried out by scrapers (type DZ-1721). When removing soil over a distance of more than 0.5 km, dump trucks (such as MAZ-503B, KRAZ-256B) or other vehicles should be used. In this case, it is recommended to load the fertile layer (also pre-shifted into piles) onto dump trucks using front-end loaders (TO-10, D-543 types), as well as single-bucket excavators (EO-4225 type) equipped with a bucket with a front shovel or grab. Payment for all these works should be provided for in the additional estimate. 2.12. The removal of the fertile soil layer, as a rule, is carried out before the onset of stable negative temperatures. In exceptional cases, in agreement with land users and authorities exercising control over land use, it is allowed to remove the fertile soil layer in winter conditions. When performing work on the removal of the fertile soil layer in the winter season, it is recommended to develop the frozen fertile soil layer with bulldozers (type DZ-27S, DZ-34S, International Harvester TD -25S) with preliminary loosening of it with three-tooth rippers (type DP-26S, DP -9S, U-RK8, U-RKE, International Harvester TD-25S), Caterpillar rippers (model 9B) and others. Loosening should be carried out to a depth not exceeding the thickness of the removed fertile soil layer. When loosening the soil with tractor rippers, it is recommended to use a longitudinally rotary technological scheme. In winter, rotary trench excavators (ETR-253A, ETR-254, ETR-254AM, ETR-254AM-01, ETR-254-05, ETR-307, ETR-309) can be used to remove and move the fertile soil layer in winter. The immersion depth of the rotor in this case should not exceed the thickness of the removed fertile soil layer. 2.13. Backfilling of the pipeline with mineral soil is carried out at any time of the year immediately after its laying. Rotary trenchers and bulldozers can be used for this. In the warm season, after filling the pipeline with mineral soil, it is compacted with vibration compactors of the D-679 type, pneumatic rollers or multiple (three to five times) passes of caterpillar tractors over the pipeline filled with mineral soil. The compaction of mineral soil in this way is carried out before filling the pipeline with the transported product. 2.14. In winter, artificial compaction of mineral soil is not carried out. The soil acquires the required density after thawing for three to four months (natural compaction). The compaction process can be accelerated by wetting (soaking) the soil with water in a backfilled trench. The same compaction method can be recommended when there is product in the pipeline during the remediation period. 2.15. The application of a fertile soil layer should be carried out only in the warm season (with normal humidity and sufficient bearing capacity of the soil for the passage of cars). For this, bulldozers are used, working in transverse strokes, moving and leveling the fertile soil layer. This method is recommended when the topsoil is over 0.2 m thick. 2.16. If it is necessary to transport the fertile soil layer to the place of application from dumps located outside the construction strip and at a distance of up to 0.5 km from it, scrapers (DZ-1721 type) can be used. With a transportation distance exceeding 0.5 km, the fertile soil layer is delivered using dump trucks, followed by leveling it with bulldozers operating in oblique or longitudinal passages. Leveling of the fertile soil layer can also be carried out by motor graders (type DZ-122, DZ-98V, equipped in the front with a blade-blade). Bringing land plots into a suitable condition is carried out in the course of work, and if this is not possible - no later than within a year after completion of work. 2.17. Control over the correctness of the performance of work in accordance with the land reclamation project is carried out by the bodies of state control over the use of land on the basis of a regulation approved by the Government. The transfer of restored lands to land users must be formalized by an act in the prescribed manner.

3. Earthwork under normal conditions

3.1. The technological parameters of earthworks used in the construction of main pipelines (the width, depth and slopes of the trench, the cross section of the embankment and the steepness of its slopes, the parameters of boreholes and wells) are set depending on the diameter of the pipeline being laid, the method of its fixing, the terrain, soil conditions and are determined project. The dimensions of the trench (depth, bottom width, slopes) are set depending on the purpose and external parameters of the pipeline, the type of ballasting, soil characteristics, hydrogeological and terrain conditions. Specific parameters of earthworks are determined by working drawings. The depth of the trench is set from the conditions of protecting the pipeline from mechanical damage when vehicles, construction and agricultural vehicles move through it. The depth of the trench when laying main pipelines is taken equal to the diameter of the pipe plus the required amount of backfilling of soil above it and is assigned by the project. At the same time, it must be (according to SNiP 2.05.06-85) not less than: · with a diameter of less than 1000 mm .............................. ................................................. ...... 0.8 m; with a diameter of 1000 mm or more .............................................. .................................................. 1.0 m; · in swamps or peat soils to be drained .................................................. 1.1 m; · in sand dunes, counting from the lower marks of inter-dune foundations... 1.0 m; in rocky soils, swampy areas in the absence of vehicles and agricultural vehicles .................................................................. ................. 0.6 m. The minimum width of the trench at the bottom is assigned by SNiP and is accepted not less than: ¨ D + 300 mm - for pipelines with a diameter of up to 700 mm; ¨ 1.5 D - for pipelines with a diameter of 700 mm or more, taking into account the following additional requirements: for pipelines with a diameter of 1200 and 1400 mm when digging trenches with slopes not steeper than 1: 0.5, the width of the trench along the bottom can be reduced to D + 500 mm , where D is the nominal diameter of the pipeline. When excavating soil with earth-moving machines, it is recommended to take the width of the trench equal to the width of the cutting edge of the working body of the machine, adopted by the construction organization project, but not less than that indicated above. When ballasting the pipeline with weighting loads or fixing it with anchor devices, the width of the trench along the bottom must be taken at least 2.2 D, and for a pipeline with thermal insulation it is established by the project. It is recommended to take the width of the trench along the bottom in curved sections from forced bending bends equal to twice the width in relation to the width in straight sections. 3.2. By the beginning of trench digging, it is recommended to obtain: a written permit for the right to excavate in the area where underground utilities are located, issued by the organization responsible for the operation of these communications; · a project for the production of earthworks, in the development of which standard technological maps are used; Work order for the crew of the excavator (if the work is carried out in conjunction with bulldozers and rippers, then for the drivers of these machines) for the production of work. 3.3. Before developing a trench, it is necessary to restore the alignment of the trench axis. When developing a trench with a single-bucket excavator, poles are placed along the axis of the trench in front of the machine and behind along an already dug trench. When digging with a rotary excavator, a vertical sight is installed on the front of it, which allows the driver, focusing on the installed milestones, to keep to the design direction of the route. 3.4. The profile for the trench must be made so that the laid pipeline along the entire length of the lower generatrix is in close contact with the bottom of the trench, and at the turning angles it is located along the line of elastic bending. 3.5. At the bottom of the trench, do not leave fragments of steel, gravel, hard lumps of clay and other objects and materials that can damage the insulation of the pipeline being laid. 3.6. The development of the trench is carried out with single-bucket excavators: ¨ in areas with pronounced hilly terrain (or strongly rugged), interrupted by various (including water) obstacles; ¨ in rocky soils loosened by drilling and blasting; ¨ on sections of curved pipeline inserts; ¨ when working in soft soils with the inclusion of boulders; ¨ in areas of high humidity and swamps; ¨ in watered soils (on rice fields and irrigated lands); ¨ in places where it is impossible or impractical to use bucket-wheel excavators; ¨ in difficult areas specially defined by the project. To develop wide trenches with slopes (in heavily watered, loose, unstable soils), single-bucket excavators equipped with a dragline are used in the construction of pipelines. Earth-moving machines are equipped with a reliable functioning sound alarm. The signaling system must be familiar to all work crews serving these machines. In areas with a calm terrain, on gently sloping hills, on soft foothills and on soft, lingering mountain slopes, work can be performed by rotary trench excavators. 3.7. Trenches with vertical walls can be developed without fastening in soils of natural moisture with an undisturbed structure in the absence of groundwater to a depth (m): · in bulk sandy and gravelly soils ......... no more than 1; · in sandy loam .............................................. ........................ no more than 1.25; in loams and clays .............................................. ...... no more than 1.5; · in especially dense non-rocky soils ....................... no more than 2. When developing trenches of great depth, it is necessary to arrange slopes of various positions depending on the composition of the soil and its humidity (Table 1).

Table 1

Permissible steepness of slopes of trenches

	The ratio of the height of the slopes to its occurrence at the depth of the excavation, m

Bulk natural moisture
Sandy and gravel wet (unsaturated)
sandy loam
Loam
Clay
Loess dry
Rocky on the plain

3.8. In waterlogged, clayey soils with rain, snow (melt) and groundwater, the steepness of the slopes of pits and trenches is reduced compared to that indicated in Table. 1 to the angle of repose. The manufacturer of works draws up a decrease in the steepness of slopes by an act. Forest-like and bulk soils become unstable when waterlogged, and during their development, wall fastening is used. 3.9. The steepness of the slopes of the trenches for the pipeline and pits for the installation of pipeline fittings is taken according to the working drawings (in accordance with Table 1). The steepness of the trench slopes in swamp areas is taken as follows (Table 2):

table 2

The steepness of the trench slopes in swamp areas

3.10. Soil development methods are determined depending on the parameters of the earthwork and the amount of work, the geotechnical characteristics of soils, the classification of soils according to the difficulty of development, local construction conditions, and the availability of earthmoving machines in construction organizations. 3.11. On linear works in the course of digging trenches for pipelines, in accordance with the working drawings, pits are developed for taps, condensate collectors and other technological units with dimensions of 2 m in all directions from the welded joint of the pipeline with fittings. Under technological breaks (overlaps), pits are developed with a depth of 0.7 m, a length of 2 m and a width of at least 1 m in each direction from the pipe wall. When constructing the linear part of the pipelines using the in-line method, the soil excavated from the trench is placed in a dump on one (left in the direction of work) side of the trench, leaving the other side free for the movement of vehicles and construction and installation works. 3.12. To prevent the collapse of the excavated soil into the trench, as well as the collapse of the walls of the trench, the base of the excavated soil dump should be located, depending on the state of the soil and weather conditions, but not closer than 0.5 m from the edge of the trench. Collapsed soil in the trench can be cleared out with a clamshell excavator just before laying the pipeline. 3.13. The development of trenches with a single-bucket excavator with a backhoe is carried out in accordance with the project without the use of manual cleaning of the bottom (this is achieved by a rational distance of the excavator moving and dragging the bucket along the bottom of the trench), which ensures the elimination of scallops at the bottom of the trench. 3.14. The development of trenches by dragline is carried out by frontal or sidewalls. The choice of development method depends on the size of the trenches along the top, the place where the pound is dumped and the working conditions. Wide trenches, especially on swampy and soft soils, are usually developed with side passages, and ordinary trenches with frontal ones. When arranging trenches, it is recommended to install the excavator from the edge of the face at a distance that ensures the safe operation of the machines (outside the prism of soil collapse): for dragline excavators with a bucket with a capacity of 0.65 m 3, the distance from the edge of the trench to the axis of movement of the excavator (during lateral development) should be at least 2.5 m. On unstable, weak soils, wooden slides are placed under the undercarriage of the excavator or they work from mobile foam sleds. When developing trenches with single-bucket excavators with a backhoe and a dragline, it is allowed to sort out soil up to 10 cm; soil shortage is not allowed. 3.15. In areas with a high level of standing groundwater, it is recommended to start trenching from lower places to ensure water runoff and drainage of overlying areas. 3.16. To ensure the stability of the walls of the trench when working in unstable soils with rotary excavators, the latter are equipped with special slopes that allow the development of trenches with slopes (steepness of 1: 0.5 or more). 3.17. Trenches, the depth of which exceeds the maximum digging depth of an excavator of this brand, are developed by excavators in combination with bulldozers.

Earthworks in rocky soils in flat terrain and in mountainous conditions

3.18. Earthworks during the construction of main pipelines in rocky soils in flat terrain with slopes up to 8° include the following operations and are performed in a certain sequence: removal and transfer to a dump for storing a fertile layer or opening a layer covering rocky soils; loosening of rocks by drilling and blasting or mechanically with its subsequent planning; · development of loosened soils by a single-bucket excavator; arrangement of a bed of soft soil at the bottom of the trench. After laying the pipeline in the trench, the following works are performed: ¨ powdering of the pipeline with loosened soft soil; ¨ installation of jumpers in a trench on longitudinal slopes; ¨ backfilling of the pipeline with rocky soil; ¨ reclamation of the fertile layer. 3.19. After removing the fertile layer, to ensure uninterrupted and more productive work of drillers and drilling equipment for loosening rocky soil, the overburden layer is removed until the rock is exposed. In areas with a soft soil layer thickness of 10 - 15 cm or less, it can not be removed. During roller drilling of charging holes and wells, soft soil is removed only for the purpose of preserving it or using it for laying a bed or powdering a pipeline. 3.20. Works on removal of overburden soil are carried out, as a rule, by bulldozers. If necessary, these works can be performed with single-bucket or rotary excavators, trench fillers, using them both independently and in combination with bulldozers (combined method). 3.21. The removed soil is laid on the trench berm in order to be able to use it for bedding and powdering. A dump of loosened rocky soil is located behind the dump of overburden soil. 3.22. With a small thickness of rocks or in the case of their strong fracturing, loosening is recommended to be carried out with a tractor ripper. 3.23. Loosening of rocky soils is carried out mainly by methods of short-delayed blasting, in which charge wells (holes) are arranged in a square grid. In exceptional cases of using the instantaneous blasting method (with wide trenches and pits), wells (holes) should be staggered. 3.24. Refinement of the calculated mass of charges and adjustment of the grid location of holes is carried out by test explosions. 3.25. Explosive work must be carried out in such a way that the rock is loosened to the design trench marks (taking into account the construction of a sand bed by 10–20 cm) and re-blasting is not required for its completion. This equally applies to the device shelves in an explosive way. When loosening the soil by explosive method, it is also necessary to ensure that pieces of loosened soil do not exceed 2/3 of the size of the excavator bucket intended for its development. Pieces of large sizes are destroyed by overhead charges. 3.26. Before the development of the trench, a rough layout of the loosened rocky soil is carried out. 3.27. When laying the pipeline, in order to protect its insulating coating from mechanical damage about the irregularities present at the bottom of the trench, a bed of soft soil with a thickness of at least 0.1 m is arranged above the protruding parts of the base. The bed is made from imported or local overburden soft soil. 3.28. For the construction of the bed, mainly rotary trench and single-bucket excavators are used, and in some cases rotary trench fillers, which develop soft overburden located on the strip next to the pipeline trench, near the roadway, and dump it on the bottom of the trench. 3.29. The soil brought by dump trucks and dumped next to the pipe (on the side opposite to the dump from the trench) is placed and leveled at the bottom of the trench using a single-bucket excavator equipped with a dragline, a scraper, a backhoe, or scraper or belt devices. With a sufficient width of the trench (for example, in the areas of ballasting the pipeline or in the sections of the turn of the route), leveling the backfilled soil along the bottom of the trench can be carried out by small-sized bulldozers. 3.30. To protect the insulating coating of the pipeline from damage by pieces of rock, when backfilling over the pipe, it is recommended to arrange a powder of soft overburden or imported soil with a thickness of at least 20 cm above the upper generatrix of the pipe. Powdering of the pipeline is performed by the same technique as backfilling under the pipeline. In the absence of soft soil, bedding and powdering can be replaced by a continuous lining of wooden slats or straw, reed, foam, rubber and other mats. In addition, bedding can be replaced by laying bags filled with soft soil or sand on the bottom of the trench at a distance of 2–5 m from one another (depending on the diameter of the pipeline) or by installing a foam bed (spraying the solution before laying the pipeline). 3.31. Earthworks during the construction of main pipelines in rocky soils in mountainous areas include the following technological processes: · arrangement of temporary roads and access roads to the highway; stripping works; Shelving arrangement; development of trenches on the shelves; backfilling of trenches and the design of the roller. 3.32. When the pipeline route passes along steep longitudinal slopes, their planning is carried out by cutting the soil and reducing the angle of elevation. These works are carried out along the entire width of the strip by bulldozers, which, cutting the soil, move from top to bottom and push it to the foot of the slope outside the construction strip. The trench profile is recommended to be placed not in bulk, but in mainland soil. Therefore, the device of the embankment is possible mainly in the area of the passage of transport vehicles.

Shelf arrangement

3.33. When passing tracks along a slope with a transverse steepness of more than 8 °, a shelf should be arranged. The design and parameters of the shelf are assigned depending on the diameter of the pipes, the dimensions of the trenches and soil dumps, the type of machines used and the methods of work and are determined by the project. 3.34. The stability of a semi-fill-shelf depends on the characteristics of the bulk soil and the soil of the foot of the slope, the steepness of the slope, the width of the bulk part, and the state of the vegetation cover. For the stability of the shelf, it is torn off with a slope of 3 - 4% towards the slope. 3.35. In sections with a transverse slope of up to 15 °, the development of recesses for shelves in non-rocky and loosened rocky soils is carried out by transverse passages of bulldozers perpendicular to the axis of the route. The completion of the shelf and its layout in this case is carried out by longitudinal passages of the bulldozer with layer-by-layer development of the soil and its movement in the semi-fill. The development of soil when arranging shelves in areas with a transverse slope of up to 15 ° can also be carried out with longitudinal passages of a bulldozer. The bulldozer first cuts and develops the soil at the transition line by half-cuts into a half-fill. After cutting the soil in the first prism at the outer edge of the shelf and moving it to the bulk part of the shelf, the soil of the next prism remote from the boundary of the transition to the semi-fill (towards the inner part of the shelf) is developed, and then in the next prisms located in the mainland soil - until the profile of the half-cut is fully developed . For large volumes of earthworks, two bulldozers are used, which are developing the shelf from both sides with longitudinal passages towards each other. 3.36. In areas with a transverse slope of more than 15 °, single-bucket excavators equipped with a front shovel are used to develop loose or non-rocky soil when arranging shelves. The excavator develops the soil within the semi-excavation and pours it into the bulk part of the shelf. During the initial development of the shelf, it is recommended to anchor it with a bulldozer or tractor. The final finishing and layout of the shelf is carried out by bulldozers. 3.37. When arranging shelves and digging trenches in mountainous areas for loosening non-separable rocks, it is possible to use tractor rippers or a drilling and blasting method of development. 3.38. When operating a tractor ripper, it is taken into account that the efficiency of its work increases if the direction of the working stroke is taken from top to bottom downhill and loosening is carried out with the choice of the longest working stroke. 3.39. Methods for drilling boreholes and wells, as well as methods for loading and detonating charges when arranging shelves in mountainous areas and trenches on shelves, are similar to the methods used when developing trenches in rocky soils on flat terrain. 3.40. It is recommended to carry out excavation work on the development of trenches on the shelves ahead of the removal of pipes to the route. Trenches on shelves in soft soils and heavily weathered rocks are developed by single-bucket and bucket-wheel excavators without loosening. In areas with dense rocky soils, before developing a trench, the soil is loosened by drilling and blasting. Earth-moving machines in trenching move along a carefully planned shelf; at the same time, single-bucket excavators move in the same way as when constructing trenches in rocky soils on flat terrain, along a deck of metal or wooden shields. 3.41. The dump of soil from the trench is placed, as a rule, at the edge of the slope of the half-ditch on the right side of the shelf along the development of the trench. If the soil dump is located in the travel zone, then for the normal operation of construction machines and mechanisms, the soil is planned along the shelf and rammed with bulldozers. 3.42. On sections of the route with longitudinal slopes up to 15 °, the development of trenches, if there are no transverse slopes, is carried out by single-bucket excavators without special preliminary measures. When working on longitudinal slopes from 15 to 36°, the excavator is pre-anchored. The number of anchors and the method of their fastening is determined by the calculation, which should be part of the project for the production of works. When working on longitudinal slopes of more than 10 °, to determine the stability of the excavator, it is checked for spontaneous shift (sliding) and, if necessary, anchoring is performed. Tractors, bulldozers, winches are used as anchors on steep slopes. The holding devices are located at the top of the slope on horizontal platforms and connected to the excavator with a cable. 3.43. On longitudinal slopes up to 22 °, excavation with a single-bucket excavator is allowed in the direction both from the bottom up and from the top down the slope. In areas with a slope of more than 22 °, to ensure the stability of single-bucket excavators, it is allowed: with a straight shovel, work only in the direction from top to bottom along the slope with the bucket forward in the course of work, and with a backhoe - only from top down along the slope, with the bucket back in the course of work. The development of trenches on longitudinal slopes up to 36 ° in soils that do not require loosening is carried out by single-bucket or rotary excavators, in previously loosened soils - by single-bucket excavators. The operation of rotary excavators is allowed on longitudinal slopes up to 36 ° when moving them from top to bottom. With slopes from 36 to 45 °, their anchoring is used. The work of single-bucket excavators with a longitudinal slope of over 22 ° and bucket-wheel excavators over 45 ° is carried out by special methods according to the project for the production of works. The development of a trench by bulldozers is carried out on longitudinal slopes up to 36 °. The construction of trenches on steep slopes from 36 ° and above can also be carried out using a tray method using scraper installations or bulldozers.

Backfilling trenches in the mountains

3.44. Backfilling of a pipeline laid in a trench on shelves and on longitudinal slopes is carried out similarly to backfilling in rocky soils on flat terrain, i.e. with a preliminary arrangement of the bed and the powdering of the pipeline with soft soil or the replacement of these operations with a lining. Lining can be made of polymeric roll materials, foamed polymers, concrete. It is forbidden to use rotting materials for lining (reed mats, wooden slats, logging waste, etc.). If the soil of the dump is planned along the shelf, then the final backfilling of the pipeline with rocky soil is carried out by a bulldozer or a rotary trencher, the remaining soil is leveled along the construction strip. In the event that the soil is located at the edge on the side of the slope of the half-ditch, then single-bucket excavators, as well as front-end bucket loaders, are used for these purposes. 3.45. The final backfilling of the pipeline on longitudinal slopes is carried out, as a rule, by a bulldozer, which moves along or at an angle to the trench, and can also be carried out from top to bottom along the slope by a trencher with its obligatory anchoring on slopes over 15 °. On slopes greater than 30° in places where the use of mechanisms is not possible, backfilling can be done manually. 3.46. For backfilling of the pipeline laid in trenches developed by the tray method on steep slopes with the soil dump located at the bottom of the slope, scraper trench-fillers or scraper winches are used. 3.47. To prevent washing away of the soil when backfilling the pipeline on steep longitudinal slopes (over 15 °), it is recommended to install jumpers.

Features of earthworks in winter conditions

3.48. Excavation work in winter is associated with a number of difficulties. The main ones are soil freezing to different depths and the presence of snow cover. When predicting soil freezing to a depth of more than 0.4 m, it is advisable to protect the soil from freezing, in particular, by loosening the soil with single or multi-point rippers. 3.49. In some places of a small area, it is possible to protect the soil from freezing by warming it with wood residues, sawdust, peat, applying a layer of foam styrene, as well as non-woven rolled synthetic materials. 3.50. To reduce the duration of thawing of frozen soil and in order to maximize the use of the fleet of earth-moving machines in warm weather, it is recommended to remove snow from the strip of the future trench during the period when positive temperatures are established.

Trench development in winter

3.51. In order to avoid the trenches being covered with snow and freezing of the soil dump during work in winter, the pace of trench development should correspond to the pace of insulation and laying work. The technological gap between the earthmoving and insulating-laying columns is recommended to be no more than two-day productivity of the earthmoving column. Methods for developing trenches in winter are prescribed depending on the time of excavation, the characteristics of the soil and the depth of its freezing. The choice of a technological scheme for earthworks in winter should provide for the preservation of snow cover on the soil surface until the start of trenching. 3.52. With a soil freezing depth of up to 0.4 m, trenching is carried out as under normal conditions: a rotary or single-bucket excavator equipped with a backhoe bucket with a bucket capacity of 0.65 - 1.5 m 3. 3.53. With a soil freezing depth of more than 0.3 - 0.4 m, before working it out with a single-bucket excavator, the soil is loosened mechanically or by drilling and blasting. 3.54. When using the drilling and blasting method for loosening frozen soils, work on the development of trenches is carried out in a certain sequence. The trench strip is divided into three sections: ¨ the area for drilling holes, charging them and blasting; ¨ zone of planning works; ¨ area for the development of loosened soil by an excavator. The distance between the grippers should ensure the safe conduct of work on each of them. Borehole drilling is carried out by motor augers, perforators and self-propelled drilling machines. 3.55. When developing frozen soil using tractor rippers with a capacity of 250 - 300 hp. work on the development of the trench is carried out according to the following schemes: 1. With a soil freezing depth of up to 0.8 m, the soil is loosened by a rack-mounted ripper to the entire freezing depth, and then it is developed with a single-bucket excavator. Excavation of loosened soil in order to avoid refreezing must be carried out immediately after loosening. 2. With a freezing depth of up to 1 m, work can be carried out in the following sequence: loosen the soil with a rack ripper in several passes, then select it with a bulldozer along the trench; The remaining soil, having a freezing thickness of less than 0.4 m, is developed with a single-bucket excavator. A trough-shaped trench in which the excavator operates is arranged with a depth of no more than 0.9 m (for an EO-4121 type excavator) or 1 m (for an E-652 excavator or similar foreign excavators) to ensure that the rear of the excavator rotates when unloading the bucket. 3 . With a freezing depth of up to 1.5 m, work can be carried out similarly to the previous scheme, with the difference that the soil in the trough must be loosened with a rack ripper before the passage of the excavator. 3.56. The development of trenches in solid frozen and permafrost soils with a freezing depth of the active layer of more than 1 m can be carried out by a complex combined sequential method, i.e. the passage of two or three different types of bucket wheel excavators. First, a trench of a smaller profile is developed, and then it is increased to design parameters using more powerful excavators. In complex sequential work, you can use either different brands of bucket-wheel excavators (for example, ETR-204, ETR-223, and then ETR-253A or ETR-254) or excavators of the same model equipped with working bodies of different sizes (for example, ETR-309). Before the passage of the first excavator, the soil is loosened, if necessary, by a heavy tractor ripper. 3.57. For the development of frozen and other dense soils, buckets of bucket-wheel excavators must be equipped with teeth hardened with wear-resistant overlays or reinforced with hard-alloy plates. 3.58. With a significant thawing depth (more than 1 m), the soil can be developed with two rotary excavators. At the same time, the first excavator develops the top layer of thawed soil, and the second - the layer of frozen soil, laying it behind the thawed soil dump. For the development of water-saturated soil, you can also use a single-bucket excavator equipped with a backhoe. 3.59. During the period of the greatest thawing of the frozen layer (at a thawing depth of 2 m or more), the trench is developed by conventional methods, as in ordinary or marshy soils. 3.60. Before laying the pipeline in a trench, the base of which has uneven frozen ground, a bed 10 cm high is made of thawed loose or finely loosened frozen soil at the bottom of the trench. 3.61. When thawing frozen soil (30 - 40 cm) for subsequent loosening of the frozen layer, it is advisable to first remove it with a bulldozer or a shovel excavator, and then work according to the same schemes as for frozen soils.

Pipeline backfilling

Earthworks in swamps and wetlands

3.63. A swamp (from a construction point of view) is an excessively moistened area of the earth's surface, covered with a layer of peat with a thickness of 0.5 m or more. Areas with significant water saturation with a peat deposit thickness of less than 0.5 m are classified as wetlands. Areas that are covered with water and do not have peat cover are waterlogged. 3.64. Depending on the patency of construction equipment and the complexity of construction and installation work during the construction of pipelines, swamps are classified into three types: First - swamps completely filled with peat, allowing the work and repeated movement of swamp equipment with a specific pressure of 0.02 - 0.03 MPa (0 ,2 - 0.3 kgf / cm 2) or the operation of conventional equipment using shields, sleighs, or temporary roads, reducing the specific pressure on the surface of the deposit to 0.02 MPa (0.2 kgf / cm 2). The second one is swamps completely filled with peat, allowing construction equipment to work and move only along shields, sledges or temporary technological roads, which reduce the specific pressure on the surface of the deposit to 0.01 MPa (0.1 kgf / cm 2). The third is swamps filled with spreading peat and water with a floating peat crust (alloy) and without an alga, allowing the operation of special equipment on pontoons or conventional equipment from floating craft.

Development of trenches for underground pipeline laying in swamps

3.65. Depending on the type of swamp, the method of laying, the time of construction and the equipment used, the following schemes for excavation in swampy areas are distinguished: ¨ trenches with preliminary excavation; ¨ development of trenches using special equipment, shields or slates, which reduce the specific pressure on the soil surface; ¨ development of trenches in winter; ¨ development of trenches by explosion. Construction on swamps should be started after a thorough examination of it. 3.66. The development of trenches with preliminary excavation is used when the depth of the peat layer is up to 1 m with an underlying base having a high bearing capacity. The preliminary removal of peat to the mineral soil is carried out by a bulldozer or an excavator. The width of the excavation formed in this case should ensure the normal operation of the excavator moving along the surface of the mineral soil and developing the trench to its full depth. The trench is arranged with a depth of 0.15 - 0.2 m below the design level, taking into account the possible slippage of the slopes of the trench in the period from the moment of development to the laying of the pipeline. When using an excavator for peat removal, the length of the created work front is assumed to be 40 - 50 m. 3.67. The development of trenches using special equipment, shields or slates, which reduce the specific pressure on the soil surface, is used in swampy areas with a peat deposit thickness of more than 1 m and having a low bearing capacity. To develop trenches in soft soils, swamp excavators equipped with a backhoe or dragline should be used. The excavator can also develop a trench while on foam sledges, which move through the swamp with the help of a winch and are located on mineral soil. Instead of a winch, one or two tractors can be used. 3.68. Excavation of trenches in the summer should be ahead of pipeline insulation if carried out in the field. The lead time depends on the characteristics of pounds and should not exceed 3 - 5 days. 3.69. The feasibility of laying pipelines through long swamps in the summer should be justified by technical and economic calculations and determined by the construction organization project. Deep and long swamps with a low bearing capacity of the peat cover should be passed in winter, and shallow small marshes and wetlands in the summer season. 3.70. In winter, as a result of soil freezing to the full (design) depth of trench development, the bearing capacity of the soil increases significantly, which makes it possible to use conventional earth-moving equipment (rotary and single-bucket excavators) without the use of sledges. In areas with deep freezing of peat, work should be carried out in a combined way: loosening the frozen layer by drilling and blasting and excavating the soil to the design mark with a single-bucket excavator. 3.71. The development of trenches in swamps of all types, especially in difficult swamps, is advisable to carry out in an explosive way. This method is economically justified in cases where it is very difficult to carry out work from the surface of the swamp, even using special equipment. 3.72. Depending on the type of swamp and the size of the required trench, various options for developing them by explosive methods are used. In open and lightly forested swamps, when developing canals 3–3.5 m deep, up to 15 m wide at the top, and the peat layer thickness up to 2/3 of the trench depth, elongated cord charges are used from waste pyroxylin gunpowder or waterproof ammonites. When laying a pipeline in deep swamps covered with forests, it is advisable to develop trenches up to 5 m deep with concentrated charges placed along the axis of the trench. In this case, there is no need for preliminary clearing of the route from the forest. Concentrated charges are placed in charging funnels, formed, in turn, by small borehole or concentrated charges. For this, waterproof ammonites are usually used in cartridges with a diameter of up to 46 mm. The depth of the charging funnel is taken taking into account the location of the center of the main concentrated charge at 0.3 - 0.5 of the channel depth. When developing trenches up to 2.5 m deep and 6-8 m wide at the top, it is effective to use borehole charges from waterproof explosives. This method can be used on swamps of types I and II both with and without forest. Wells (vertical or inclined) are located along the axis of the trench at a calculated distance from each other in one or two rows, depending on the design width of the trench bottom. The diameter of the wells is 150 - 200 mm. Inclined wells at an angle of 45 - 60 ° to the horizon are used when it is necessary to eject the soil on one side of the trench. 3.73. The choice of explosives, the mass of the charge, the depth, the location of the charges in the plan, the methods of blasting, as well as the organizational and technical preparation for the production of drilling and blasting operations and the testing of explosive materials are set out in the "Technical Rules for Explosive Operations on the Day Surface" and in the "Methodology for calculating explosive parameters during construction of canals and trenches in swamps” (M., VNIIST, 1970).

Backfilling of the pipeline in swamps

3.74. Methods for performing work when backfilling trenches in swamps in the summer depend on the type and structure of the swamps. 3.75. In swamps of types I and II, backfilling is carried out either by swamp bulldozers, when the movement of such machines is ensured, or by dragline excavators on a widened or normal course, moving along the sledges on dumps of soil, previously planned by two passages of the bulldozer. 3.76. The excess soil obtained during backfilling is placed in an over-trench roller, the height of which is determined taking into account the draft. If there is not enough soil for backfilling the trench, it should be developed by an excavator from lateral reserves, which should be laid from the axis of the trench at a distance of at least three of its depths. 3.77. In deep swamps with a fluid consistency of peat, inclusions of sapropelite or covering with drifts (type III swamps), after laying the pipeline on a solid base, it can not be covered. 3.78. Backfilling of trenches in swamps in winter is carried out, as a rule, by bulldozers on widened caterpillars.

Surface laying of the pipeline in the embankment

3.79. The method of erecting embankments is determined by the conditions of construction and the type of earthmoving machines used. Soil for filling the embankment in flooded areas and in swamps is being developed in nearby quarries located on elevated places. The soil in such quarries is usually more mineralized and therefore more suitable for a stable embankment. 3.80. The development of soil in quarries is carried out by scrapers or single-bucket or rotary excavators with simultaneous loading into dump trucks. 3.81. In floating bogs, when filling the embankment, the floating crust (alloy) of small thickness (no more than 1 m) is not removed, but immersed to the bottom. In this case, if the thickness of the crust is less than 0.5 m, the filling of the embankment directly onto the raft is carried out without the device of longitudinal slots in the raft. With a raft thickness of more than 0.5 m, longitudinal slots can be arranged in the raft, the distance between which should be equal to the base of the future earth embankment below. 3.82. The slitting should be done by blasting. Powerful rafts before the start of backfilling are destroyed by explosions of small charges laid in a checkerboard pattern on a strip equal to the width of the earthen strip below. 3.83. Embankments through swamps with low bearing capacity are constructed from imported soil with preliminary peat removal at the base. In swamps with a bearing capacity of 0.025 MPa (0.25 kgf / cm 2) and more, embankments can be poured without peat directly on the surface or along brushwood lining. In bogs of type III, embankments are dumped mainly on the mineral bottom due to the extrusion of the peat mass by the soil mass. 3.84. It is recommended to build embankments with excavation in swamps with a peat cover thickness of not more than 2 m. The expediency of peat removal is determined by the project. 3.85. In swamps and other watered areas that have water runoff across the embankment, the filling is carried out from well-draining coarse-grained and gravelly sands, gravel, or special culverts are arranged. 3.86. It is recommended to backfill the embankment in a certain sequence: · the first layer (25 - 30 cm high above the swamp), delivered by dump trucks, is backfilled using the pioneer method of sliding. The soil is unloaded at the edge of the swamp, and then pushed towards the embankment by a bulldozer. Depending on the length of the swamp and the conditions of the entrance, the embankment is erected from one or both banks of the swamp; · the second layer (up to the design mark of the bottom of the pipe) is poured in layers with compaction immediately along the entire length of the transition; · the third layer (up to the design level of the embankment) is backfilled after the pipeline is laid. The leveling of the soil along the embankment is carried out by a bulldozer, backfilling of the laid pipeline is carried out by single-bucket excavators. 3.87. Embankments are poured during the construction process, taking into account the subsequent sedimentation of the soil; the amount of settlement is set by the project depending on the type of soil. 3.88. Backfilling of embankments with preliminary removal of peat at the base is carried out in a pioneering way from the “head”, and without peat removal both from the head part and from the plank road located along the axis of the pipeline.

Earthworks in the construction of concreted or ballasted pipelines

3.89. Earthworks for the construction of a pipeline ballasted with reinforced concrete weights or a concreted pipeline are characterized by increased volumes of work and can be performed both in summer and in winter. 3.90. With the underground method of laying a concreted gas pipeline, the trenches must develop the following parameters: ¨ trench depth - correspond to the project and be at least D n + 0.5 m (D n is the outer diameter of the concreted gas pipeline, m); ¨ the width of the trench along the bottom in the presence of slopes of 1: 1 or more - not less than D n + 0.5 m. When developing a trench for alloying the pipeline, its width along the bottom is recommended to be at least 1.5 D n. 3.91. The minimum gap between the load and the trench wall when ballasting the gas pipeline with reinforced concrete weighting loads should be at least 100 mm, or the width of the trench along the bottom when ballasting with loads or fixing with anchor devices is recommended to be at least 2.2 D n. 3.92. In view of the fact that pipelines concreted or ballasted with reinforced concrete loads are laid in swamps, swampy and watered areas, earthwork methods are similar to earthworks in swamps (depending on the type of swamps and season). 3.93. To develop trenches for pipelines of large diameters (1220, 1420 mm), concreted or ballasted with reinforced concrete loads, the following method can be used: a bucket-wheel excavator in the first pass opens a trench with a width equal to about half the required trench width, then the soil is returned to its place by a bulldozer; then, with the second pass of the excavator, the soil is selected on the remaining unloosened part of the trench and again returned to the trench by a bulldozer. After that, the loosened soil for the entire profile is selected by a single-bucket excavator. 3.94. When laying a pipeline in areas of predicted flooding, ballasted with reinforced concrete weights, in winter conditions, the method of group installation of weights on the pipeline can be used. In this regard, the trench can be developed in the usual way, and widening it for a group of goods can be done only in certain areas. Earthworks in this case are carried out as follows: a rotary or single-bucket (depending on the depth and strength of the frozen soil) excavator opens a trench of the usual (for a given diameter) width; then the sections of the trench where the cargo groups are to be installed are covered with soil. In these places, on the sides of the developed trench, holes are drilled for explosive charges in one row, so that after blasting the total width of the trench in these places would be sufficient to install weighting loads. Then the soil, loosened by the explosion, is removed by a single-bucket excavator. 3.95. The backfilling of a pipeline that is concreted or ballasted with weights is carried out using the same methods as when backfilling a pipeline in swamps or frozen soils (depending on the conditions of the route and the time of year).

Peculiarities of excavation technology when laying gas pipelines with a diameter of 1420 mm in permafrost soils

3.96. The choice of technological schemes for arranging trenches in permafrost soils is carried out taking into account the depth of soil freezing, its strength characteristics and the time it takes to complete the work. 3.97. The construction of trenches in the autumn-winter period with a freezing depth of the active layer from 0.4 to 0.8 m using single-bucket excavators of the EO-4123, ND-150 types is carried out after preliminary loosening of the soil with rack rippers of the D-355, D-354 type and others , which loosen the soil to the entire freezing depth in one technological step. With a freezing depth of up to 1 m, loosening it is carried out by the same rippers in two passes. With a greater freezing depth, the development of trenches with single-bucket excavators is carried out after preliminary loosening of the soil by drilling and blasting. Boreholes and wells along the trench strip are drilled using drilling machines such as BM-253, MBSH-321, Kato and others in one or two rows, which are charged with explosives and explode. With a freezing depth of the active layer of soil up to 1.5 m, loosening it for the development of trenches, especially those located no further than 10 m from existing structures, is carried out using the borehole method; with a depth of soil freezing more than 1.5 m - by the borehole method. 3.98. When arranging trenches in permafrost soils in winter with their freezing to the entire depth of development, both in swamps and in other conditions, it is advisable to use mainly rotary trench excavators. Depending on the strength of the developed soil, the following technological schemes are used for trenching: in permafrost soils with a strength of up to 30 MPa (300 kgf / cm 2), trenches are developed in one technological step using bucket-wheel excavators of the ETR-254, ETR-253A, ETR-254A6 ETR types -254AM, ETR-254-05 bottom width 2.1 m and maximum depth up to 2.5 m; ETR-254-S - bottom width 2.1 m and depth up to 3 m; ETR-307 or ETR-309 - with a bottom width of 3.1 m and a depth of up to 3.1 m. D-355A or D-455A develop a trough-shaped excavation with a width of 6 - 7 m and a depth of up to 0.8 m (depending on the required design depth of the trench), then in this excavation, using the appropriate types of bucket-wheel excavators for a given diameter of the pipeline, a trench of the design profile is developed for one technological pass. In permafrost soils with a strength of up to 40 MPa (400 kgf / cm 2), the development of wide-profile trenches for laying loaded pipelines with a diameter of 1420 mm with reinforced concrete loads of the UBO type in areas with a depth of 2.2 to 2.5 m and a width of 3 m is carried out by a rotary trench excavator of the type ETR-307 (ETR-309) in one pass, or by a complex-combined and sequential method. The development of trenches in such areas by the in-line complex-combined method, first, along the border of one side of the trench, a pioneer trench is developed by a rotary trench excavator of the ETR-254-01 type with a working body width of 1.2 m, which is filled with a bulldozer of the D-355A, D-455A or DZ type -27C. Then, at a distance of 0.6 m from it, a second trench 1.2 m wide is developed by a rotary excavator of the ETR-254-01 type, which is also covered with loosened soil using the same bulldozers. The final development of the design profile of the trench is carried out by a single-bucket excavator of the ND-1500 type, which, simultaneously with the selection of the soil of the pioneer trenches loosened by rotary excavators, also develops the soil pillar between them. A variant of this scheme in areas of soil with a strength of up to 25 MPa (250 kgf / cm 2) can be the use of bucket-wheel excavators of the ETR-241 or 253A type instead of ETR-254-01 for extracting the second pioneer trench. In this case, there are practically no works on the development of the rear sight. When developing trenches of such parameters in permafrost soils with a strength of 40 to 50 MPa (from 400 to 500 kgf / cm 2), the complex of earth-moving machines (according to the previous scheme) additionally includes tractor rack rippers of the D-355, D-455 type for preliminary loosening the top most durable soil to a depth of 0.5 - 0.6 m before the operation of bucket-wheel excavators. For the development of trenches in soils of higher strength - over 50 MPa (500 kgf / cm 2), when loosening and excavation of the soil pillar with a single-bucket excavator is of great difficulty, it is necessary to loosen it by drilling and blasting before working with single-bucket excavators. To do this, drilling machines such as BM-253, BM-254 drill a series of holes in the body of the pillar at intervals of 1.5 - 2.0 m to a depth exceeding the design depth of the trench by 10 - 15 cm, which are charged with explosive charges for loosening and explode. After that, excavators of the ND-1500 type excavate all the loosened soil until the design profile of the trench is obtained. · trenches for pipelines loaded with reinforced concrete weights (UBO type) with a depth of 2.5 to 3.1 m are developed in a certain technological sequence. In areas with soil strength up to 40 MPa (400 kgf / cm 2) and more, at first, tractor rack rippers based on D-355A or D-455A loosen the upper permafrost layer of soil on a strip 6 - 7 m wide to a depth of 0.2 - 0 .7 m depending on the required final trench depth. After removing the loosened soil with bulldozers in the resulting trough-shaped excavation with a rotary trench excavator of the ETR-254-01 type, a pioneer cut-trench 1.2 m wide is developed along the border of the project trench. After filling this slot with excavated loosened soil, at a distance of 0.6 m from the edge the second pioneer trench is cut by another rotary excavator of the ETR-254-01 type, which is also filled with the help of bulldozers of the D-355, D-455 type. Then, with a single-bucket excavator of the ND-1500 type, a trench of the full design profile is developed simultaneously with the soil of the pillar. · in areas of heavily icy high-strength permafrost soils with a cutting resistance of more than 50 - 60 MPa (500 - 600 kgf / cm 2), trenching should be carried out with preliminary loosening of soils by drilling and blasting. At the same time, depending on the required depth of trenches, drilling of holes in a checkerboard pattern in 2 rows using machines of the BM-253, BM-254 type should be carried out in a trough-shaped recess with a depth of 0.2 (with a trench depth of 2.2 m) to 1.1 m (at a depth of 3.1 m). To eliminate the need for work on the arrangement of a trough-shaped excavation, it is advisable to introduce drilling machines of the MBSH-321 type. 3.99. On sections of the route in permafrost, low-icy soils, where gas pipelines are to be ballasted with mineral soil using NCM devices, it is recommended to take the following trench parameters: bottom width no more than 2.1 m, depth depending on the amount of backfill and the presence of a heat-insulating screen - from 2.4 up to 3.1 m. The development of trenches in such areas up to 2.5 m deep in soils with a strength of 30 MPa (300 kgf / cm 2) is recommended to be carried out on a full profile with rotary trench excavators of the ETR-253A or ETR-254 type. Trenches up to 3 m deep in such soils can be developed by rotary excavators of the ETR-254-02 and ETR-309 types. In soils with a strength of more than 30 MPa (300 kgf / cm 2), mechanized earth-moving complexes for the implementation of the technological scheme described above should additionally include tractor-mounted rippers of the D-355 A or D-455A type for preliminary loosening of the most durable upper layer of permafrost soil on depth of 0.5 - 0.6 m before working out the trench profile with rotary excavators of the indicated brands. In areas with soil strength up to 40 MPa (400 kgf / cm 2), it is also possible to use a technological scheme with sequential sinking and excavation of a trench profile along the axis of the route with two rotary excavators: first, ETR-254-01 with a rotor width of 1.2 m, and then ETR-253A, ETR-254 or ETR-254-02 depending on the required trench depth in this area. For the effective development of wide trenches of ballasted gas pipelines with a diameter of 1420 mm in solid permafrost soils, a sequential-complex method is recommended with two powerful rotary trench excavators of the ETR-309 type (with different parameters of the working body), in which the first excavator equipped with interchangeable unified working bodies with a width of 1.2 ¸ 1.5 and 1.8 ¸ 2.1 m, first cuts a pioneer trench ~ 1.5 m wide, and then the second excavator, equipped with two mounted side rotary cutters, moving sequentially, refines it to the design dimensions of 3 ´ 3 m required to accommodate the pipeline with ballasting devices. In soils with a strength of more than 35 MPa (350 kgf / cm 2), the specified sequentially combined technological scheme must include preliminary loosening of the upper frozen layer of soil to a depth of 0.5 m with tractor rack rippers of the D-355A or D-455A type. 3.100. In areas with the occurrence of especially strong permafrost soils with a strength of 50 MPa or more (500 kgf / cm 2), it is recommended to develop trenches with such parameters with single-bucket excavators of the ND-1500 type with preliminary loosening of the frozen layer by drilling and blasting. To drill holes to full depth (up to 2.5 - 3.0 m), it is necessary to use drilling machines such as BM-254 and MBSH-321. 3.101. In all cases, when performing excavation work on trenching in these soil conditions in the summer, in the presence of a thawed top layer of soil, it is removed from the trench strip using bulldozers, after which the trenching work is carried out according to the technological schemes given above, taking into account the design profile of the trench and the strength of the permafrost in this area. When the top layer of soil thaws, in the event of its transition to a plastic or fluid state, which makes it difficult to conduct earthworks for loosening and developing the underlying permafrost soil, this layer of soil is removed by a bulldozer or a shovel excavator, and then the permafrost soil, depending on its strength, is developed by the above methods. Embankments on permafrost soils, as a rule, should be built from imported soil mined in quarries. In this case, it is not recommended to take soil for an embankment on the gas pipeline construction site. A quarry should be arranged (if possible) in loose-frozen soils, since a change in their temperature slightly affects their mechanical strength. In the process of erection, the embankment must be backfilled, taking into account its subsequent settlement. The increase in its height in this case is set: when performing work in the warm season and filling the embankment with mineral soil - by 15%, when performing work in the winter and filling the embankment with frozen soil - by 30%. 3.102. Backfilling of a pipeline laid in a trench made in permafrost soils is carried out as under normal conditions, if after laying the pipeline immediately after the development of the trench and backfilling (if necessary), the soil of the dump was not subjected to freezing. In the event of freezing of the soil of the dump, in order to avoid damage to the insulating coating of the pipeline, it must be sprinkled with imported thawed fine-grained soil or finely loosened frozen soil to a height of at least 0.2 m from the top of the pipe. Further backfilling of the pipeline is carried out with a pound of dump using a bulldozer or, preferably, a rotary trencher, which is capable of developing a dump with freezing to a depth of 0.5 m. If the dump is frozen deeper, it must first be loosened mechanically or by drilling and blasting. When backfilling with frozen soil, a soil bead is arranged above the pipeline, taking into account its settlement after thawing.

Drilling of wells and installation of piles for above-ground laying of pipelines

3.103. The method of erecting pile foundations is prescribed depending on the following factors: ¨ permafrost and soil conditions of the route; ¨ time of year; ¨ technology of work performance and results of technical and economic calculations. Pile foundations in the construction of pipelines in areas of permafrost are usually built from prefabricated piles. 3.104. The construction of pile foundations is carried out depending on the soil conditions in the following ways: driving piles directly into the plastic-frozen soil or into previously developed leader holes (drilling method); installation of piles in pre-thawed soil; installation of piles in pre-drilled and filled with a special solution wells; installation of piles using a combination of the above methods. Driving piles into the frozen mass can only be carried out in high-temperature plastic-frozen soils with a temperature above -1 ° C. It is recommended to drive piles into such soils with a content of coarse and solid inclusions up to 30% after drilling leader wells, which are formed by immersing special pipes leaders (with a cutting edge at the bottom and a hole in the side top). The leader hole diameter is 50 mm less than the smallest size of the pile cross-section. 3.105. The technological sequence of operations for installing piles in previously developed leader wells is as follows: ¨ the pile driving mechanism drives the leader to the design mark; ¨ the leader with the core is retrieved by the winch of the excavator, which moves with the leader pipe to the next well, where the whole process is repeated; ¨ the pile is driven into the formed leader hole by the second pile driving mechanism. 3.106. If there are coarse-grained inclusions in the soil (more than 40%), it is not advisable to use leader drilling, since the initial force to extract the leader increases significantly and the core is shedding back into the well. 3.107. In heavy clays and loams, the use of bored piles is also impractical due to the fact that the core in the pipe is wedged and is not forced out of the leader. Leader wells can be arranged by drilling by thermomechanical, shock-rope or other methods. 3.108. In cases where it is impossible to use bored piles, they are immersed in wells previously drilled by thermomechanical, mechanical or shock-rope drilling machines. The technological sequence of operations when drilling wells with percussion-rope drilling machines is as follows: arrange a platform for installing the unit, which must be strictly horizontal. This is especially important when drilling wells on slopes, where the layout of the site for installing the unit and for smooth entry to it is carried out by a bulldozer by raking up snow and watering it with water (for freezing the upper layer); in the summer, the site is planned by a bulldozer; · a well is drilled with a diameter of 50 mm larger than the largest transverse dimension of the pile; · the well is filled with a sand-clay mortar heated to 30 - 40 ° C in the volume of approximately 1/3 of the well, based on the complete filling of the space between the pile and the wall of the well (the solution is prepared directly on the track in mobile boilers using drill cuttings with the addition of fine-grained sand in the amount 20 - 40% of the volume of the mixture; it is desirable to deliver gelling water to hot mobile containers or heat it during the work process); Install the pile in the well with a pipelayer of any brand. When the pile is driven to the design mark, the solution should be squeezed out to the surface of the earth, which serves as evidence of the complete filling of the space between the walls of the well and the surface of the pile with the solution. The process of drilling a well and driving a pile into a drilled well should not last more than 3 days. in winter and more than 3-4 hours in summer. 3.109. The technology of drilling wells and installing piles using thermomechanical drilling machines is set out in the "Instructions on the technology of drilling wells and installing piles in frozen soils using thermomechanical drilling machines" (VSN 2-87-77, Minneftegazstroy). 3.110. The duration of the process of freezing piles with permafrost soil depends on the season of work, characteristics of frozen soil, soil temperature, pile design, composition of sand-clay mortar and other factors and should be specified in the work design.

Trench backfill

3.111. Before starting work on backfilling the pipeline in any soil, it is necessary to: ¨ check the design position of the pipeline; ¨ check the quality and, if necessary, repair the insulating coating; ¨ to carry out the work envisaged by the project to protect the insulating coating from mechanical damage (planning the bottom of the trench, laying the bed, powdering the pipeline with loose soil); ¨ arrange entrances for the delivery and maintenance of the excavator and bulldozer; ¨ obtain written permission from the customer to backfill the laid pipeline; ¨ issue a work order for the production of work to the driver of a bulldozer or trench filler (or the crew of a shovel excavator, if backfilling is performed by an excavator). 3.112. It is recommended to fill up the trench immediately after laying work (after ballasting the pipeline or fixing it with anchor devices). 3.113. When backfilling the pipeline in rocky and frozen soils, the safety of pipes and insulation from mechanical damage is ensured by powdering over the laid pipeline from soft (thawed) sandy soil to a thickness of 20 cm above the upper generatrix of the pipe, or by installing protective coatings provided by the project. 3.114. Backfilling of the pipeline under normal conditions is carried out mainly by bulldozers and rotary-type trench fillers. 3.115. Backfilling of the pipeline by bulldozers is carried out: straight, oblique parallel, oblique and combined passages. In the cramped conditions of the construction strip, as well as in places with a reduced right of way, work is carried out with oblique parallel and oblique cross passages by a bulldozer or a rotary trench filler. 3.116. If there are horizontal curves on the pipeline, the curved section is first filled up, and then the rest. Moreover, backfilling of a curved section begins from its middle, moving alternately towards its ends. 3.117. In areas of terrain with vertical curves of the pipeline (in ravines, beams, on hills, etc.), backfilling is carried out from top to bottom. 3.118. With large volumes of backfilling, it is advisable to use trench fillers in combination with bulldozers. At the same time, at first, the backfill is carried out with a trench filler, which during the first pass has maximum productivity, and then the remaining part of the dump is shifted into the trench by bulldozers. 3.119. Backfilling of a pipeline laid in a trench with a dragline is carried out in cases where the operation of equipment in the area of the dump is impossible, or at large distances of backfilling with soil. In this case, the excavator is located on the side of the trench opposite the dump, and the soil for backfilling is taken from the dump and poured into the trench. 3.120. After backfilling on non-reclaimed lands above the pipeline, a soil roller is arranged in the form of a regular prism. The height of the roller should match the amount of possible soil settlement in the trench. On recultivated lands in the warm season, after the pipeline is backfilled with mineral soil, it is compacted with pneumatic rollers or caterpillar tractors by multiple passes (three to five times) over the backfilled pipeline. The compaction of mineral soil in this way is carried out before filling the pipeline with the transported product.

4. Quality control and acceptance of earthworks

4.1. The quality control of earthworks consists in the systematic monitoring and verification of the compliance of the work performed with the project documentation, the requirements of the joint venture in compliance with the tolerances (given in Table 3), as well as technological maps as part of the PPR.

Table 3

Permits for the production of earthworks

Name of tolerance

Tolerance (deviation), cm

Tolerance (deviation) illustration

Half the width of the trench along the bottom in relation to the staking axis

Deviation of marks when planning a lane for the operation of bucket-wheel excavators

The total thickness of the backfill layer above the pipeline

Embankment height

4.2. The purpose of control is to prevent the occurrence of marriage and defects in the process of work, to exclude the possibility of accumulation of defects, to increase the responsibility of performers. 4.3. Depending on the nature of the operation (process) being performed, operational quality control is carried out directly by performers, foremen, foremen or a special representative-controller of the customer's company. 4.4. Defects identified during the control, deviations from the designs, requirements of the SP, PPR or technological standards for maps should be corrected before the start of subsequent operations (works). 4.5. Operational quality control of earthworks includes: ¨ verification of the correctness of the transfer of the actual axis of the trench with the design position; ¨ verification of marks and lane width for the operation of bucket-wheel excavators (in accordance with the requirements of the project for the production of works); ¨ checking the profile of the bottom of the trench with measuring its depth and design marks, checking the width of the trench along the bottom; ¨ checking the slopes of trenches depending on the structure of the soil specified in the project; ¨ checking the thickness of the backfill layer at the bottom of the trench and the thickness of the pipeline powder layer with soft soil; ¨ control of the thickness of the layer of backfill and dike of the pipeline; ¨ checking the marks of the top of the embankment, its width and the steepness of the slopes; ¨ the size of the actual radii of curvature of the trenches in the sections of horizontal curves. 4.6. The width of trenches along the bottom, including those in sections ballasted with reinforced concrete weights or screw anchor devices, as well as in sections of curves, is controlled by templates lowered into the trench. The strip marks for the operation of rotary excavators are controlled by a level. The distance from the center line to the trench wall along the bottom in dry sections of the route should be at least half the design width of the trench, this value should not be exceeded by more than 200 mm; in flooded and swampy areas - more than 400 mm. 4.7. The actual turning radius of the trench in plan is determined by the theodolite (the deviation of the actual axis of the trench in a straight section cannot exceed ± 200 mm). 4.8. Compliance of the trench bottom marks with the design profile is checked using geometric leveling. The actual elevation of the trench bottom is determined at all points where the design elevations are indicated in the working drawings, but at least 100, 50 and 25 m - respectively for pipelines with a diameter of up to 300, 820 and 1020 - 1420 mm. The actual elevation of the trench bottom at any point should not exceed the design one and may be less than it by up to 100 mm. 4.9. In the case when the project provides for adding loose soil to the bottom of the trench, the thickness of the leveling layer of loose soil is controlled by a probe lowered from the trench berm. The thickness of the leveling layer must be at least the design; tolerance for layer thickness is given in table. 3 . 4.10. If the project provides for powdering the pipeline with soft soil, then the thickness of the layer of powder laid in the trench of the pipeline is controlled by a measuring ruler. The thickness of the powder layer is at least 200 mm. Allowed deviation of the layer thickness within the limits specified in table. 2. 4.11. The marks of the recultivated strip are controlled by geometric leveling. The actual elevation of such a strip is determined at all points where the design elevation is indicated in the land reclamation project. The actual mark must be at least the design mark and not exceed it by more than 100 mm. 4.12. On non-reclaimed lands, using a template, the height of the roller is controlled, which must be at least the design height and not exceed it by more than 200 mm. 4.13. When laying an aboveground pipeline in an embankment, its width is controlled by a tape measure, the width of the embankment on top should be 1.5 diameters of the pipeline, but not less than 1.5 m and exceed it by no more than 200 mm. The distance from the axis of the pipeline is controlled by a tape measure. The slope of the embankment is controlled by the template. Reducing the transverse dimensions of the embankment against the design one is allowed by no more than 5%, with the exception of the thickness of the soil layer above the pipeline in sections of convex curves, where a decrease in the backfill layer above the pipeline is not allowed. 4.14. In order to be able to carry out complex work, it is necessary to control the shifting pace of trench development, which must correspond to the shifting pace of insulation and laying work, and in case of factory insulation, the pace of insulating pipe joints and laying the finished pipeline into the trench. Backward trenching is generally not allowed. 4.15. Acceptance of completed earthworks is carried out upon commissioning of the entire pipeline. Upon delivery of completed objects, the construction organization (general contractor) is obliged to transfer to the customer all the technical documentation, which should contain: · working drawings with the changes made to them (if any) and a document on the execution of the changes made; Intermediate acts for hidden work; drawings of earthworks made according to individual projects in difficult construction conditions; a list of imperfections that do not interfere with the operation of an earthen structure, indicating the timing of their elimination (in accordance with the agreement and contract between the contractor and the customer); · a list of permanent benchmarks, geodetic signs and route layout indicators. 4.16. The procedure for acceptance and delivery of completed works, as well as the execution of documentation, must be carried out in accordance with the current rules for the acceptance of works. 4.17. For underground and above-ground laying, the pipeline throughout its entire length must rest on the bottom of the trench or the bed of the embankment. The correctness of the arrangement of the foundation for the pipeline and its laying (the bottom of the trench along the length, the depth of laying, the support of the pipeline along the entire length, the quality of the filling of the bed from soft soil) must be checked by the construction organization and the customer on the basis of geodetic control before filling the pipeline with soil with the preparation of the corresponding act. 4.18. Particular attention in earthworks is paid to the preparation of the base - a bed for pipelines of large diameters, in particular 1420 mm, the acceptance of which must be carried out using leveling surveys throughout the pipeline. 4.19. Delivery and acceptance of main pipelines, including earthworks, is formalized by special acts.

5. Environmental protection

5.1. Works during the construction of main pipelines should be carried out taking into account the requirements for environmental protection established by federal and republican laws, building codes and regulations, including: ¨ Fundamentals of land legislation of the USSR and the Union republics; ¨ Law on the Protection of Atmospheric Air; ¨ Law on the Protection of the Aquatic Environment; ¨ SNiP 2.05.06-85; SNiP III-42-80; SNiP 3.02.01-87; ¨ Departmental building codes “Construction of main pipelines. Technology and Organization” (VSN 004-88, Minneftegazstroy. M., 1989); ¨ "Instructions for the performance of construction work in the protected zones of the main pipelines of the Mingazprom" (VSN-51-1-80, M, 1982), as well as these provisions. 5.2. The most significant changes in the natural environment in permafrost areas can occur as a result of a violation of the natural heat exchange of soils with the atmosphere and a sharp change in the water-thermal regime of these soils, which occurs as a result of: damage to the moss and vegetation cover along the route and the area adjacent to it; clearing of forest vegetation; Disruption of the natural regime of snow deposits. The combined effect of these factors can significantly increase the adverse effect on the thermal regime of permafrost, especially heavily icy subsiding soils, which can lead to changes in the overall environmental situation over a wide area. In order to avoid these unpleasant consequences, it is necessary: ¨ excavation work on subsiding soils should be carried out mainly during the period of stable negative air temperatures with the presence of snow cover; ¨ traffic in a snowless period is recommended only within the roadway, the movement of heavy wheeled and caterpillar vehicles outside the road is not allowed; ¨ all construction work on the route is carried out in the shortest possible time; ¨ the preparation of the territory allotted for the construction of pipelines in such areas is recommended to be carried out according to the technology that allows the maximum preservation of the vegetation cover on it; ¨ after completion of work on backfilling the pipeline in certain sections, immediately carry out land reclamation, removal of construction debris and residual materials, without waiting for the commissioning of the entire pipeline; ¨ all damage to the vegetation cover on the construction strip at the end of work should be immediately covered with fast-growing grass that takes root well in these climatic conditions. 5.3. When performing work, any activity leading to the formation of new lakes or the drainage of existing reservoirs, a significant change in the natural drainage of the territory, a change in the hydraulics of streams or the destruction of significant sections of river beds is not recommended. When performing any work, exclude the possibility of backwater and surface water in areas located outside the right of way. If it is impossible to fulfill this requirement, water passes should be arranged in the soil dumps, including special culverts (siphons). 5.4. When excavating trenches for pipelines, land should be stored in two separate dumps. The upper sod layer is laid in the first dump, and the rest of the soil is laid in the second. After laying the pipeline in the trench, the soil returns to the trench strip in the reverse order with layer-by-layer compaction. Excess soil from the second dump is recommended to be removed to low relief places in such a way as not to disturb the natural drainage regime of the territory.

6. Safety in earthworks

6.1. The technical staff of construction organizations must ensure that the workers comply with the Safety Rules provided for by the current documents: · SNiP III-4-80 "Safety in construction" (M., Stroyizdat, 1980); · "Safety regulations for the construction of main steel pipelines" (M., Nedra, 1982); · "Unified Safety Rules for Explosive Operations" (M., Nedra, 1976). Persons who have been instructed, trained and tested on safety in accordance with the approved current departmental Regulations are allowed to perform work. 6.2. It is not allowed to work earth-moving machines under the wires of an existing power line. When working near a power line, electrical safety measures must be observed (SNiP III-4-80 "Rules for the installation of electrical installations" [PUE]). 6.3. All workers on the track must be familiar with the warning signs used in the production of earthworks. 6.4. Manufacturing enterprises are required to take measures to ensure fire safety and industrial sanitation. 6.5. Places of work, transport and construction machines must be provided with first aid kits with a set of hemostatic, dressings and other means necessary for first aid. Employees must be familiar with the rules for providing first aid. 6.6. Water for drinking and cooking in order to avoid gastrointestinal diseases is recommended to be used on the basis of the conclusion of the local sanitary and epidemiological station only from sources suitable for this purpose. Drinking water must be boiled. 6.7. When performing work in the northern regions of the country in the spring and summer, it is recommended that all workers be provided with protective (Pavlovsky nets, closed overalls) and repellents (dimethyl phthalate, diethyltoluamide, etc.) against mosquitoes, midges, horseflies, midges and instruct on the procedure for using these means . When working in areas where the encephalitis tick is spread, all workers must be given anti-encephalitis vaccinations. 6.8. In winter, special attention should be paid to the implementation of measures to prevent frostbite, including the creation of heating points. Workers should be trained in first aid for frostbite.

3.1. The dimensions and profiles of the trenches are established by the project depending on the purpose and diameter of the pipelines, soil characteristics, hydrogeological and other conditions.

3.2. The width of the trenches along the bottom must be at least D + 300 mm for pipelines with a diameter of up to 700 mm (where D is the nominal diameter of the pipeline) and 1.5 D for pipelines with a diameter of 700 mm or more, taking into account the following additional requirements:

for pipelines with a diameter of 1200 and 1400 mm when digging trenches with slopes not steeper than 1:0.5, the width of the trench along the bottom can be reduced to D + 500 mm;

when excavating soil with earth-moving machines, the width of the trenches should be taken equal to the width of the cutting edge of the working body of the machine, adopted by the construction organization project, but not less than that indicated above;

the width of the trenches along the bottom in curved sections from forced bending bends should be equal to twice the width in relation to the width in straight sections;

the width of the trenches along the bottom when ballasting the pipeline with weighting loads or fixing it with anchor devices must be at least 2.2D, and for pipelines with thermal insulation it is established by the project.

3.3. The steepness of trench slopes should be taken in accordance with SNiP 3.02.01-87, and those developed in swamps - according to Table. 1.

Table 1

In silty and quicksand soils that do not ensure the preservation of slopes, trenches are developed with fastening and drainage. Types of fastening and drainage measures for specific conditions should be established by the project.

3.4. When digging trenches with bucket-wheel excavators, in order to obtain a more even surface of the bottom of the trenches at the design level and ensure a snug fit of the laid pipeline to the base along the entire length along the axis of the pipeline at a width of at least 3 m, preliminary planning of the strip microrelief should be carried out in accordance with the project.

3.5. The development of trenches in swamps should be carried out with single-bucket backhoes on widened or conventional tracks from sledges, draglines or special machines.

When laying pipelines through swamps using the alloy method, it is advisable to develop trenches and floating peat crust using an explosive method, using elongated cord, concentrated or borehole charges.

Paragraphs 3.6 and 3.7 shall be deleted.

3.8. In order to prevent deformation of the profile of the dug trench, as well as freezing of the soil heap, the shifting rates of insulation-laying and excavation work should be the same.

The technologically necessary gap between the earthmoving and insulating-laying columns must be indicated in the project for the production of works.

The development of trenches in the backlog in soils (with the exception of rocky ones in the summer), as a rule, is prohibited.

Explosive loosening of rocky soils should be carried out before the pipes are taken to the route, and loosening of frozen soils is allowed after laying the pipes on the route.

3.9. When developing trenches with preliminary loosening of rocky soil using a drilling and blasting method, soil sorting should be eliminated by adding soft soil and compacting it.

3.10. Foundations for pipelines in rocky and frozen soils should be leveled with a layer of soft soil with a thickness of at least 10 cm above the protruding parts of the foundation.

3.11. When constructing pipelines with a diameter of 1020 mm or more, the bottom of the trench should be leveled along the entire length of the route: on straight sections after 50 m; on vertical curves of elastic bending after 10 m; on vertical curves of forced bending after 2 m; when constructing pipelines with a diameter of less than 1020 mm only on difficult sections of the route (vertical angles of rotation, sections with rugged terrain), as well as at crossings over railways and roads, ravines, streams, rivers, beams and other obstacles for which individual workers are developed blueprints.

3.12. By the time the pipeline is laid, the bottom of the trench must be leveled in accordance with the design.

Laying the pipeline in a trench that does not comply with the project is prohibited.

3.13*. Backfilling of the trench is carried out immediately after the lowering of the pipeline and the installation of ballast weights or anchor devices, if the ballasting of the pipeline is provided for by the project. Places for installation of stop valves, tees of control and measuring points of electrochemical protection are filled up after their installation and welding of cathode terminals.

When backfilling the pipeline with soil containing frozen clods, crushed stone, gravel and other inclusions larger than 50 mm in diameter, the insulating coating should be protected from damage by adding soft soil to a thickness of 20 cm above the upper generatrix of the pipe or by installing protective coatings provided by the project.

Note. The post-shrinkage restoration of main pipelines (laying on design marks, restoration of design ballasting, backfilling of soil in trenches, restoration of embankments, etc.) is carried out in accordance with the procedure established by the Rules on Contracts for Capital Construction, approved by the Decree of the Council of Ministers of the USSR of December 24, 1969. No. 973.

table 2

	Tolerance value (deviation), cm
Half the width of the trench along the bottom in relation to the staking axis
Deviation of marks when planning a lane for the operation of bucket-wheel excavators
Deviation of trench bottom marks from the project:
when excavating soil with earthmoving machines
in the development of soil by drilling and blasting
The thickness of the bed layer of soft soil at the bottom of the trench
The thickness of the layer of powder from soft soil above the pipe (with subsequent backfilling with rocky or frozen soil)
The total thickness of the backfill layer above the pipeline
Embankment height

3.14*. Soft backfilling of the bottom of the trench and backfilling of the pipeline laid in rocky, stony, gravel, dry lumpy and frozen soils with soft soil can be replaced, in agreement with the design organization and the customer, with continuous reliable protection made of non-rotting, environmentally friendly materials.

3.15. Earthworks during the construction of main pipelines must be carried out in compliance with the tolerances given in Table. 2.