MINISTRY OF HIGHWAYS OF THE RSFSR

STATE ROAD DESIGN, SURVEY AND SCIENTIFIC RESEARCH INSTITUTE
HYPRODORNIAS

REFERENCE
REPORT ON ENGINEERING GEOLOGICAL SURVEYS
WHEN DESIGNING HIGHWAYS
AND BRIDGE CROSSINGS

Approved at a meeting of the NTS section

Giprodornii of the design part

Protocol No. 10 of 12/23/86

MOSCOW 1987

Standard report on engineering-geological surveys for the design of highways and bridges / Giprodornia. - M.: CBNTI of the Ministry of Road Transport of the RSFSR. 1987.

The main objective of issuing the Standard is to unify the forms of field, laboratory and office documentation of geotechnical engineering work.

The standard report includes all main types of notes, drawings, statements and graphs issued by the Geological Service of Giprodornia. When compiling the Standard, the requirements of current state standards, regulatory documents and manuals to them were taken into account.

Developed by Ch. geologist - engineer R.T. Vlasyuk (technical department of Giprodornia) in the development of previously published (in 1985) samples of registration of engineering-geological passports for highway surveys.

Director of the Institute

Ph.D. tech. Science E.K. Kuptsov

1. GENERAL PROVISIONS

The technical report on engineering and geological surveys must contain all the data necessary for the development of design and estimate documentation corresponding to the stage of highway design.

Reports on detailed engineering-geological surveys (for drawing up a project and detailed design) should consist of an explanatory note, the text of which is illustrated with drawings and photographs, graphic applications, statements, engineering-geological passports of bridge crossings, overpasses, places for individual design of the roadbed, sites for buildings and structures, soil deposits and road construction materials.

Instructions for the preparation and composition of engineering-geological passports are given in the samples of registration of engineering-geological passports for surveying highways and structures on them, published by the technical department of Giprodornia in 1985.

This Standard provides general guidance on the scope of a geotechnical survey report. In each individual case, it is determined individually depending on local conditions, especially when it comes to surveying bridge crossings.

Sample report title page

MINISTRY OF HIGHWAYS OF THE RSFSR
HYPRODORNIAS
(Branch)

REPORT
ON ENGINEERING GEOLOGICAL WORK FOR
DRAFTING A PROJECT (WORKING DRAFT)
FOR CONSTRUCTION (RECONSTRUCTION)
HIGHWAY (BRIDGE CROSSING
THROUGH R. …………………..)………………………………….

Head of Department I.O. Surname

Chief geologist (specialist) of the department I.O. Surname

Chief (senior) geologist

expedition (party) I.O. Surname

19... g.

2. SCHEME OF EXPLANATORY NOTE

2.1. Introduction

Administrative and geographical boundaries of the survey area.

On whose instructions the work was carried out.

Work production time.

The degree of exploration of the territory of the survey object.

Organization of field work (number of parties, detachments).

Work producers (chief geologist, party leader, senior engineer, etc.). Position, surname of the author of the report.

Technology of engineering-geological works (drilling pits and boreholes, type and brand of machines, geophysical exploration methods, field methods of soil research).

Completeness and quality of work performed.

2.2. Natural conditions of the area, work

2.2.1. Climate:

General climatic characteristics of the area indicating climatic zones along the route sections;

Precipitation, its distribution by month, showers, long-term average and maximum thickness of snow cover, the number of days with snowfall, the duration of the period of snowstorms and the number of days with snowstorms, the duration of the winter period;

Information from the road maintenance service about snow drifts on the roads in the area of ​​the route;

Number of days with thaws, ice, fogs;

Average, maximum and minimum air temperatures, transition of average daily temperatures through 0 and 5 degrees; depth of soil freezing, absolute and relative air humidity, dates of freezing and opening of rivers, information about snow avalanches and mudflows for mountainous areas;

Wind; prevailing winds by season, winds with speeds exceeding 4 m/s. A winter wind rose, and in the southern arid regions a summer wind rose.

2.2.2. Relief and hydrography:

General geomorphological characteristics of the highway route area;

Regionalization of the route according to the relief;

Provision of natural water flow, waterlogging;

Hydrographic network of the route area;

List of medium and large bridge crossings.

2.2.3. Soils and vegetation:

General characteristics of soils in the region as a whole and in sections;

Description of the main soil types along the highway route;

Vegetation cover of the highway route area;

Possibility of using vegetation for road construction.

2.2.4. Geology, tectonics and hydrogeology:

Features of the tectonics of the area, seismicity;

Brief description of the geological structure of the road route area as a whole and in individual sections;

Characteristics and depth of bedrock;

Characteristics of Quaternary rocks;

Conditions of surface runoff, formation of perched water;

Groundwater, distribution and features of its occurrence;

Estimated level of the groundwater horizon and methods for its determination during engineering-geological survey;

Chemical composition of ground and surface water (aggressive properties towards concrete, suitability for mixing concrete, suitability for drinking);

Sources of water for technical purposes (irrigation when laying subgrade).

2.3.1. Soils:

General characteristics of soils of engineering-geological elements along the entire length of the route and in sections;

Granulometric composition and physical properties of the main soil differences (natural moisture, optimal moisture and density, determined on a standard Soyuzdornia compaction device, plasticity limits) soil categories according to the difficulty of development;

Assessment of soils as a building material for the construction of subgrades and as the foundation of road structures;

Chemical composition (content of water-soluble salts in the area of ​​development of saline soils) according to data from local agricultural enterprises and according to our own laboratory research.

2.3.2. Modern physical and geological processes:

The presence and intensity of manifestation of modern physical and geological processes, their impact on the operation and stability of road structures;

The presence of landslides, screes, karst, swamps, wet excavations and other places that require individual design of the roadbed.

2. 3 .3. Engineering and geological construction conditions:

Features of the construction of sections of standard and individual design of the roadbed;

Features of the construction of artificial structures and ASG facilities.

Note. if necessary, it can be compiled for the highway route and road structures as a whole or separately for the roadbed, small artificial structures, bridge crossings and overpasses and ASG objects.

2.4. Road construction materials

The literary and archival sources used are survey data from previous years, as well as data to resolve the issue of providing the site with building materials.

Assessment of the geological structure of the considered highway laying area in terms of the possibility and conditions for obtaining road construction materials.

A brief general description of the surveyed and explored deposits of road-building materials by groups of stone, gravel, and sand. Brands and classes of materials according to SNiP.

Near-route soil deposits for filling embankments. Their location, development and transportation conditions.

Availability of operating quarries and bases for processing road construction materials. Quality of materials, conditions of their receipt and delivery.

Availability of local industrial enterprises that produce waste suitable for use as materials for road construction work. Conditions for receipt and delivery of waste. Quality of waste as road construction materials.

Analysis of the supply of construction materials with local and imported road construction materials and their qualitative characteristics.

2.5. Results of the survey of existing roads

2.5.1. Subgrade:

Characteristics of the subgrade in general and in specific areas;

Deformation, damage and destruction of the subgrade;

The degree of compaction of the subgrade;

Condition of drainage;

2.5.2. Road wear:

The condition of the road surface in general and in specific areas;

Availability and thickness of structural layers of road pavement;

Composition and characteristics of structural layers of road pavement;

2.6. conclusions

The main results of engineering-geological studies of the highway route and road structures.

Notes

1. The text of the note is illustrated with photographs of production processes, views of the local landscape, characteristic outcrops, individual difficult places, crossings of watercourses, individual sections showing the condition of existing roads, etc.

2. The climate of an area can be represented by graphs of climate data, curves of temperatures, precipitation and wind roses.

For arid areas, you should apply not only the winter wind rose, but also the summer one.

3. When submitting a report to the geological fund, its composition and design must meet the requirements for reporting materials submitted to the geological fund of the USSR Ministry of Geology and the Mosoblgeofond.

4. GEOLOGICAL STRUCTURE

AND HYDROGEOLOGICAL CONDITIONS

The geological structure of the studied area of ​​the projected on-site linear engineering networks to an explored depth of 5.0 m involves Quaternary loamy-sandy loam deposits of cover (pQ ​​III - IV), fluvioglacial (fQ II), glaciolacustrine (lgQ II) and moraine (gQ II) genesis , covered from the surface with a soil-vegetative layer (Fig. 3-7).

Soil-vegetative layer with the roots of herbaceous vegetation is represented by frozen loamy humified soil of a brownish-brown color, 0.1-0.3 m thick.

Cover deposits (pQ III - IV) distributed everywhere, occur on the surface and are represented semi-solid loams, in the top of the layer to a depth of 0.5 m – frozen, dark brown and brownish-brown, dusty, with plant debris. The thickness of cover loams varies from 0.6 to 1.6 m.

Fluvioglacial deposits (fQ II) are ubiquitous, lie under cover loams from a depth of 0.7-1.8 m and are represented by:

a) refractory loams, brown and light yellow-brown, light and heavy, with inclusions of gravel and pebbles up to 3-5%, sandy, with nests of yellow-brown, fine, wet sand. They lie in a consistent layer with a thickness of 1.4-2.3 m.

b) plastic sandy loams, brown and yellowish-brown, sometimes soft-plastic, sandy loams, with layers and lenses of yellow-brown, silty, wet sand. They occur from a depth of 2.2-4.0 m in a thin layer 0.5-1.4 m thick.

Lacustrine-glacial deposits (lgQ II) are common in the southeastern part of the site, lie under fluvioglacial deposits from a depth of 3.5-4.7 m and are represented semi-solid loams (to clays), less often - hard-plastic, light gray and gray-brown, with a greenish tint, heavy, with the inclusion of gravel and pebbles up to 10%, exposed thickness up to 0.8 m.

Moraine deposits (gQ II) lie from depths of 3.9-4.9 m under fluvioglacial or glaciolacustrine deposits and are represented semi-solid loams, heavy, red-brown and brownish-brown, with the inclusion of pebbles, debris and crushed stone up to 10-15%, slightly sandy. The revealed thickness of moraine loams is up to 1.1 m.

Hydrogeological conditions researched sites

Page 9

5. ENGINEERING GEOLOGICAL CHARACTERISTICS

AND SOIL PROPERTIES

According to the data of drilling 21 wells to a depth of 5.0 m, laboratory studies of soils, as well as taking into account archival materials, the site of the designed on-site linear engineering networks is represented by soils of four stratigraphic-genetic complexes (SGK), containing 5 engineering-geological elements (IGE), with a relatively uniform, but with wedging out of individual IGE, layering of soils, including:

Table 5.1

Genesis and age		Soil name	Power
		Semi-solid loam
		Refractory loam
		Plastic sandy loam
		Loam (up to clay) semi-solid	opened
		Semi-solid loam	opened

Below is a brief description of the main stratigraphic-genetic complexes and identified IGEs.

I . Cover deposits (pQ III) are distributed everywhere, lie under the soil-vegetation layer and are represented by semi-solid (in the roof - frozen to a depth of 0.5 m) silty loam, 0.6-1.6 m thick.

IGE-1. Semi-solid cover loam , with plant residues.

According to laboratory tests, IGE-1 loam is characterized by the following average values ​​of physical property parameters:

humidity at the rolling boundary W p -19.8%;

plasticity number I p -13.2%;

natural humidity W p -21.5%;

turnover index I L - 0.13;

soil density r – 1.94 g/cm 3 ;

porosity coefficient e –0.70.

In terms of the degree of frost hazard, cover loams IGE-1, taking into account the fluidity index I L = 0.13, are slightly heaving, with a relative heaving deformation from 0.01 to 0.035 units. (Table B-27, GOST 25100).

II . Complex of water-glacial (fluvioglacial) deposits time of regression of the Moscow glacier (fQ II ) has a widespread distribution, lies from a depth of 0.7-1.8 m under cover loams and is represented mainly by loamy-sandy loam deposits, with nests and layers of sand. Two engineering-geological elements are identified as part of the water-glacier complex:

- loam IGE-2 - distributed everywhere, lying in a consistent layer with a thickness of 1.4-2.3 m;

Page 10

- sandy loam IGE-3 - widespread everywhere, occurs in the form of a thin layer with a thickness of 0.5 m to 1.4 m.

IGE-2. Fluvioglacial loam, refractory, light and heavy, with inclusions of gravel and pebbles up to 3-5%, sandy, with pockets of fine, wet sand.

According to laboratory tests, IGE-2 loam is characterized by the following average values ​​of physical property parameters:

plasticity number I p -11.3%;

natural humidity W p -21.9%;

turnover index I L - 0.34;

soil density r – 1.99 g/cm 3 ;

porosity coefficient e –0.66.

In terms of frost hazard, IGE-2 fluvioglacial loams, taking into account the fluidity index I L = 0.34, are medium heaving, with a relative heaving deformation from 0.035 to 0.07 units. (Table B-27, GOST 25100).

IGE-3. C fluvioglacial plastic uppis , sometimes soft plastic loam, sandy, with layers and lenses of dusty, wet sand.

According to laboratory tests, sandy loam IGE-3 is characterized by the following average values ​​of physical property parameters:

humidity at the rolling boundary W p -18.0%;

plasticity number I p -6.7%;

natural humidity W p -21.3%;

turnover rate I L - 0.50;

soil density r – 2.01 g/cm 3 ;

porosity coefficient e –0.62.

In terms of the degree of frost hazard, sandy loam IGE-3, located in the seasonal freezing zone, taking into account the fluidity index I L = 0.50, is medium heaving, with a relative heaving deformation from 0.035 to 0.07 units. (Table B-27, GOST 25100).

III . Complex of lacustrine-glacial deposits (lgQ II ) has a local distribution (in the south-eastern part of the site), lies from a depth of 3.5-4.7 m under fluvioglacial deposits and is represented by loamy-clayey deposits, exposed up to 0.8 m thick.

IGE-4. Loam (up to clay) lacustrine-glacial, semi-solid , heavy, with the inclusion of gravel and pebbles up to 10%.

According to laboratory tests, IGE-4 loam is characterized by the following average values ​​of physical property parameters:

humidity at the rolling boundary W p -19.7%;

plasticity number I p -16.7%;

natural humidity W p -22.1%;

fluidity index I L - 0.15;

soil density r – 1.98 g/cm 3 ;

porosity coefficient e –0.68.

Page 11

In terms of frost hazard, IGE-4 lacustrine-glacial loams are outside the freezing zone.

I V. Complex of glacial deposits (moraine of the Moscow age glacier retreat (g Q II ) It is widespread within the area, represented by loamy rocks, sometimes slightly sandy, containing up to 15% of rounded and unrounded clastic material.

IGE-5. Morainic loam, semi-solid , sandy, with the inclusion of gravel, pebbles, gruss and crushed stone up to 10-15%, lies from a depth of 3.9-4.9 m in a layer with an exposed thickness of up to 1.1 m.

According to laboratory tests, IGE-5 loam is characterized by the following average values ​​of physical property parameters:

humidity at the rolling boundary W p -16.1%;

plasticity number I p -13.3%;

natural humidity W p -17.4%;

turnover rate I L - 0.10;

soil density r – 2.09 g/cm 3 ;

porosity coefficient e –0.52.

In terms of frost hazard, moraine loams IGE-5 are outside the freezing zone.

The main indicators of the physical properties of soils are summarized in Table 5.2.

Table 5.2. Indicators of physical properties of soils

Stratigraphic-genetic complex		Name engineering geological element	Soil density,	Density of soil particles, g/cm3	Plasticity number	Turnover rate	Porosity coefficient	Humidity level	Relative frost heave strain
				r S	I P	I L		S r	ε fn
		Loam semi-solid
		Loam refractory
		Plastic sandy loam
		Loam (to clay) semi-solid
		Loam semi-solid

The distribution of the identified engineering-geological elements, the conditions of their occurrence on the site of the projected construction of on-site communication routes are shown on engineering-geological sections and well cores (drawing Nos. 3-13).

Page 12

The physical characteristics of soils obtained from laboratory studies and their statistical processing (according to GOST 20522-96) are given in Appendix 3. The values ​​of statistical criteria for the variability of indicators are within acceptable limits.

According to chemical analyses, the soils of the site are non-saline, pH = 6.8-7.4.

In terms of the degree of aggressiveness to concrete grades W 4, W 6, W 8 and to reinforced concrete structures (SNiP 2.03.11-85), the soils are non-aggressive (Appendix 4).

Assessment of the corrosive activity of soils in the aeration zone towards:

lead cable sheaths – high (in terms of organic content);

aluminum cable sheaths – average (for chlorine ion);

carbon steel – average (in terms of electrical resistivity).

The standard depth of seasonal freezing according to SNiP 23-01-99 and the “Manual for the design of foundations of buildings and structures (to SNiP 2.02.01-83*)” is: for loam – 132 cm, for sandy loam, fine and silty sand – 160 cm.

Standard and calculated (at a=0.85 and a=0.95) values ​​of the main physical and mechanical characteristics of soils identified by IGE in accordance with SNiP 2.02.01 -83*, SP 11-105-97 are given in Table 5.3. text of the report “Recommended standard and calculated values ​​of the characteristics of the physical and mechanical properties of soils.”

Regulatory

Page 14

6. CONCLUSION

	Engineering and geological surveys on the site of the designed on-site linear engineering networks for the cottage village "Yuzhnye Gorki" (Phase II), located at the address: Moscow region, Leninsky district, near the village. Meshcherino were carried out at stage P in order to study engineering and geological conditions.
	Geomorphologically, the territory of the cottage village is confined to a gently undulating water-glacial plain. The surface of the site is free of buildings and vegetation and has a slight slope to the southwest. Absolute surface elevations vary from 171.51 to 176.06 m (at the mouths of the workings). Modern physical and geological processes that could negatively affect the construction of the designed on-site linear utility networks were not noted in the surveyed territory of the cottage village during the survey process.
	The geological structure of the studied area of ​​the projected on-site linear engineering networks to an explored depth of 5.0 m involves Quaternary loamy-sandy loam deposits of cover (pQ ​​III - IV), fluvioglacial (fQ II), glaciolacustrine (lgQ II) and moraine (gQ II) genesis , covered from the surface with a soil-vegetative layer, thickness 0.1-0.3 m.
	Hydrogeological conditions of the projected construction site are characterized by the absence of permanent groundwater within the explored depths (up to 5 m) for the period of survey (March 2010). However, during periods of prolonged heavy rains and active spring snowmelt, as well as in the event of disruption of surface runoff and leaks from the designed water-carrying communications, temporary groundwater of the “overwater” type may appear in sandy varieties of fluvioglacial deposits at depths of 2.2-4.0 m. The relative aquicludes for these waters are glaciolacustrine and moraine loams.
	In the explored strata, four stratigraphic-genetic complexes (SGK) were identified, containing 5 engineering-geological elements (EGE), the conditions of distribution and occurrence of which are shown on engineering-geological sections and well cores, and the recommended standard and calculated values ​​of the characteristics of the physical and mechanical properties of soils identified by IGE are given in Table 5.3. text of the report “Recommended standard and calculated values ​​of the characteristics of the physical and mechanical properties of soils.”
	The corrosive activity of soils in the aeration zone to lead cable sheaths is high; to aluminum cable sheaths, as well as to carbon steel – medium. The soils of the selected IGE are non-aggressive to concrete of all grades in terms of water resistance on any cement, and are also non-aggressive to reinforced concrete structures.
	The standard freezing depth for loams is 1.32 m, for sandy loams – 1.60 m.
	Page 15 According to the degree of frost heaving, soils located in the seasonal freezing zone range from weak to medium heaving.
	According to the degree of development of karst-suffosion hazard, the work site belongs to the non-hazardous category (MGSN 2.07-01).
	Based on a set of factors, the engineering and geological conditions of the studied site are of medium complexity (II category of complexity according to appendix B SP 11-105-97, part I), and in general, favorable for the construction of the designed on-site communications.
	Based on the engineering and geological conditions of the projected construction site, the project should provide for the protection of steel, aluminum and lead structures from the aggressive influence of soils.

Page 16

BIBLIOGRAPHY

Stock

Technical report on geotechnical surveys. On-site communication routes for the cottage village "Yuzhnye Gorki" at the address: Moscow region, Leninsky district, near the village of Korobovo, LLC "Orgstroyizyskaniya", inv. No. IG-T-09-11, 2009

Technical report on geotechnical surveys. Water intake unit for the cottage village "Yuzhnye Gorki" near the village of Korobovo, Leninsky district, Moscow region, LLC "Orgstroyizyskaniya", inv. No. IG-T-09-12, 2009

3. A manual for the design of foundations of buildings and structures (SNiP 2.02.01-83), Moscow, Stroyizdat, 1986.

4. MGSN 2.07-01. Moscow city building codes. Foundations, foundations and underground structures. Moscow, 2003

5. TSN IZ-2005 MO. Territorial building codes. Organization of engineering surveys to ensure the safety of urban development projects in the Moscow region.

6. The procedure for performing engineering surveys for the preparation of design documentation, construction, reconstruction, major repairs of capital construction projects in the Moscow region. (Ministry of Construction Complex of the Moscow Region, 2009)

7. Instructions for engineering-geological and geoecological surveys in Moscow dated March 11, 2004, Moskomarkhitektura, M., 2004.

Building regulations

SNiP 11-02-96 – “Engineering surveys for construction. Basic provisions".

SP 11-105-97 “Engineering and geological surveys for construction.”

SP 11-104-97 “Engineering and geodetic surveys for construction.”

SP 11-102-97 “Engineering and environmental surveys for construction.”

SP 50-101-2004 “Design and installation of foundations and foundations of buildings and structures.”

SNiP 2.02.01 -83* “Foundations of buildings and structures”

SNiP 2.03.11-85 “Protection of building structures from corrosion.”

SNiP 2.06.15-85 “Engineering protection of territories from flooding and flooding.”

SNiP 3.02.01-87 “Earth structures, foundations and foundations.”

SNiP 23-01-99 “Building climatology”

SNiP 22-02-2003 “Engineering protection of territories, buildings and structures from hazardous geological processes.”

Page 17

State standards

GOST 25100-95 “Soils. Classification".

GOST 12071-2000 “Soils. Selection, packaging, transportation, storage of samples.”

GOST 5180-84 “Soils. Methods for laboratory determination of physical characteristics."

GOST 12536-79 “Soils. Methods for laboratory determination of granulometric composition."

GOST 12248-96 “Soils. Methods for laboratory determination of strength and deformability characteristics.”

GOST 20522-96 “Soils. Methods for statistical processing of test results."

GOST 9.602-2005 “Underground structures. General requirements for corrosion protection."

GOST 4979-94 “Underground waters. Domestic, drinking and industrial water supply. Methods of chemical analysis".

GOST 21.302-96 “Conventional graphic symbols in documentation for engineering and geological surveys.”

GOST 21.101-97 “Basic requirements for design and working documentation.”

introduction Explanatory note

Environmental strategy of JSC AK Transneft ( explanatorya note) 1. Introduction In accordance with the approved “Environmental Policy of OJSC” ... planned in the amount of 5000.0 thousand rubles. - With introduction put into operation at Almetyevsk RNU 117 km...

Clay soils are one of the most common types of rocks. The composition of clay soils includes very fine clay particles, the size of which is less than 0.01 mm, and sand particles. Clay particles have the shape of plates or flakes. Clay soils have a large number of pores. The ratio of pore volume to soil volume is called porosity and can range from 0.5 to 1.1. Porosity characterizes the degree of soil compaction. Clay soil absorbs and retains water very well, which when frozen turns into ice and increases in volume, increasing the volume of the entire soil. This phenomenon is called heaving. The more clay particles the soil contains, the more susceptible it is to heaving.

Clay soils have the property of cohesion, which is expressed in the ability of the soil to maintain its shape due to the presence of clay particles. Depending on the content of clay particles, soils are classified into clay, loam and sandy loam.

The ability of soil to deform under external loads without breaking and retain its shape after the load is removed is called plasticity.

The plasticity number Ip is the difference in humidity corresponding to two states of the soil: at the yield boundary WL and at the rolling boundary W p , W L and W p are determined according to GOST 5180.

Table 1. Classification of clay soils according to the content of clay particles.

Priming	particles by mass, %	Plasticity number IP
Loam

The plasticity number of clay soils determines their construction properties: density, humidity, compression resistance. As humidity decreases, density increases and compressive strength increases. As humidity increases, density decreases and compressive strength also decreases.

Sandy loam.

Sandy loam contains no more than 10% clay particles, the rest of this soil consists of sand particles. Sandy loam is practically no different from sand. There are two types of sandy loam: heavy and light. Heavy sandy loam contains from 6 to 10% clay particles, in light sandy loam the content of clay particles is from 3 to 6%. When rubbing sandy loam on a damp palm, you can see sand particles; after shaking off the soil, traces of clay particles are visible on the palm. Lumps of sandy loam in a dry state easily crumble and crumble on impact. Sandy loam almost does not roll into a rope. A ball rolled from moistened soil crumbles under light pressure.

Due to its high sand content, sandy loam has a relatively low porosity of 0.5 to 0.7 (porosity is the ratio of pore volume to soil volume), so it can hold less moisture and therefore be less susceptible to heaving. The lower the porosity of dry sandy loam, the greater its load-bearing capacity: with a porosity of 0.5 it is 3 kg/cm2, with a porosity of 0.7 - 2.5 kg/cm2. The bearing capacity of sandy loam does not depend on humidity, so this soil can be considered non-heaving.

Loam.

Soil in which the content of clay particles reaches 30% by weight is called loam. In loam, as in sandy loam, the content of sand particles is greater than clay particles. Loam has greater cohesion than sandy loam and can be preserved in large pieces without breaking up into small ones. Loams can be heavy (20% -30% clay particles) and light (10% - 20% clay particles).

When dry, soil pieces are less hard than clay. Upon impact, they crumble into small pieces. When wet, they have little plasticity. When rubbing, sand particles are felt, lumps are crushed more easily, larger grains of sand are present against the background of finer sand. A rope rolled out from damp soil is short. A ball rolled from moistened soil, when pressed, forms a cake with cracks along the edges.

The porosity of loam is higher than sandy loam and ranges from 0.5 to 1. Loam can contain more water and, therefore, is more susceptible to heaving than sandy loam.

Loams are characterized by fairly high strength, although they are susceptible to slight subsidence and cracking. The load-bearing capacity of loam is 3 kg/cm2, when moistened it is 2.5 kg/cm2. Loams in a dry state are non-heaving soils. When moistened, clay particles absorb water, which turns into ice in winter, increasing in volume, which leads to heaving of the soil.

Clay.

Clay contains more than 30% clay particles. Clay has great cohesion. When dry, clay is hard; when wet, it is plastic, viscous, and sticks to your fingers. When you rub the sand particles with your fingers, you cannot feel the sand particles; it is very difficult to crush the lumps. If you cut a piece of raw clay with a knife, the cut will have a smooth surface on which grains of sand are not visible. When squeezing a ball rolled from raw clay, a flat cake is obtained, the edges of which do not have cracks.

The porosity of clay can reach 1.1; it is more susceptible to frost heaving than all other soils. Clay in a dry state has a load-bearing capacity of 6 kg/cm2. Clay saturated with water can increase in volume by 15% in winter, losing its load-bearing capacity up to 3 kg/cm2. When saturated with water, clay can change from a solid to a fluid state.

Table 2 shows methods by which you can visually determine the type and characteristics of clay soils.

Table 2. Determination of the mechanical composition of clayey soils.

Soil name	View through a magnifying glass	Plastic
	Homogeneous fine powder, almost no sand particles	Rolls out into a rope and rolls up into a ring
Loam	Predominantly sand, particles clay 20 – 30%	When rolled out it turns out tourniquet, when coiled the ring falls apart
	Sand particles predominate with a small admixture of clay particles	When trying to roll out the tourniquet breaks into small pieces

Classification of clay soils.

Most clay soils in natural conditions, depending on their water content, can be in different states. The construction standard (GOST 25100-95 Classification of soils) defines the classification of clay soils depending on their density and moisture content. The state of clay soils is characterized by the fluidity index IL - the ratio of the difference in humidity corresponding to two states of the soil: natural W and at the rolling boundary Wp, to the plasticity number Ip. Table 3 shows the classification of clayey soils according to their fluidity index.

Table 3. Classification of clayey soils by fluidity index.

Type of clay soil	Turnover rate
Sandy loam:
plastic
Loams and clays:
semi-solid
tight-plastic
soft plastic
fluid-plastic

According to the particle size distribution and plasticity number Ip, clay groups are divided according to Table 4.

Table 4. Classification of clay soils according to particle size distribution and plasticity number

	Plasticity number	particles (2-0.5mm),% by weight
Sandy loam:
sandy
dusty
Loam:
light sandy
light dusty
heavy sandy
heavy dusty
Clay:
light sandy
light dusty
		Not regulated

Based on the presence of solid inclusions, clayey soils are divided according to Table 5.

Table 5. Solids content in clay soils .

Types of clay soils
Sandy loam, loam, clay with pebbles (crushed stone)
Sandy loam, loam, clay, pebbly (crushed stone) or gravelly (gristy)

Among clayey soils the following should be distinguished:

Peat soil;

Subsidence soils;

Swelling (heaving) soils.

Peat soil is sand and clay soil, containing in its composition in a dry sample from 10 to 50% (by weight) peat.

According to the relative content of organic matter Ir, clay soils and sands are divided according to Table 6.

Table 6. Classification of clay soils according to organic matter content

Type of soil	Relative content of organic matter Ir, units.
Heavily peated
Medium peated
Lightly peated
With an admixture of organic substances

Swelling soil is a soil that, when soaked with water or other liquid, increases in volume and has a relative swelling strain (under free swelling conditions) greater than 0.04.

Subsidence soil is a soil that, under the influence of external load and its own weight or only from its own weight when soaked with water or other liquid, undergoes vertical deformation (subsidence) and has a relative subsidence deformation e sl ³ 0.01.

Depending on the subsidence and its own weight during soaking, subsidence soils are divided into two types:

• type 1 - when the soil subsidence due to its own weight does not exceed 5 cm;
• type 2 - when the soil subsidence due to its own weight is more than 5 cm.

According to the relative subsidence deformation e sl, clayey soils are divided according to Table 7.

Table 7. Relative subsidence deformation of clayey soils.

Types of clay soils	Relative subsidence strain e sl, d.u.
Non-sagging
subsidence

Heaving soil is dispersed soil, which, during the transition from thawed to frozen state, increases in volume due to the formation of ice crystals and has a relative frost heave deformation e fn ³ 0.01. These soils are not suitable for construction; they must be removed and replaced with soil with good bearing capacity

According to the relative swelling deformation without load e sw, clayey soils are divided according to Table 8.

Table 8. Relative swelling deformation of clay soils.

Types of clay soils	Relative swelling deformation without load e sw, e.
Non-swelling
Low swelling
Medium swelling
Highly swelling

According to this indicator, soils are divided into sand, sandy loam, light, medium and heavy loam, as well as light, medium and heavy clay.

From this article you will learn:
- Why it is impossible to determine the composition of the soil by its color;
- How to determine the amount of clay particles at home using the wet method;
- How to conduct a dry test for loam and sandy loam.

Why is it impossible to determine the composition of the soil by its color?

Sand, sandy loam, loam, clay - some gardeners mistakenly judge the mechanical composition of the soil by its color. With such an assessment, they often incorrectly determine the number of clay particles, thinking that loam is sandy loam, and mistaking loam for clay.

The color of the soil on the site and its shades depend not only on the clay content, but also on its mineralogical composition. The fact is that the color of the earth, in addition to humus, is influenced by its tendency to contain aluminum compounds, and sometimes iron and manganese. Under waterlogging conditions, a gley horizon with a bluish color is formed, due to the content of aluminoferrosilicates that appear when iron interacts with clay minerals. Iron and manganese form oxide compounds (poisonous to plants), giving a rusty-ocher color.

Often repeating the color of loam, sandy loam is not an ideal soil and requires testing. Therefore, the mechanical composition of the soil must be determined by the degree of its cohesion.

How to determine whether your site has loam or clay

For field conditions, there is an old technique that does not require any tools and is accessible to everyone. In this method, called “wet”, a soil sample is moistened (if the water is far away, then you can drool) and mixed until it forms a dough. Roll a ball from the prepared soil in the palm of your hand and try to roll it into a cord (experts sometimes colloquially call it a sausage) about 3 mm thick or a little more, then roll it into a ring with a diameter of 2-3 cm.

Test result Does not form either a ball or a cord. It forms a ball that cannot be rolled out into a cord (sausage). Only its rudiments are obtained. It forms a cord that can be rolled into a ring, but it turns out to be very fragile and easily falls apart when rolled off the palm or when you try to pick it up. Light loam. It forms a continuous cord that can be rolled into a ring, but it turns out with cracks and fractures. Medium loam. Easily rolls out into a cord. The ring comes out with cracks. Heavy loam. It can be rolled into a long thin clay cord, which produces a ring of high plasticity without cracks.

Sometimes, in their desire to determine the soil on the site as accurately as possible, gardeners leaf through dozens of old volumes of geological reference books in search of answers to the questions of what is older, loam or clay, or which ancient sea is to blame for the fact that gardening near Moscow is on sandy soil. But in order to increase soil productivity, the good old “wet method” is definitely enough. The only thing: you need to be careful when identifying sandy loams and loams, as they can be dusty.

Loam or sandy loam. Dry method for silty soils

These varieties are distinguished by the dry method as follows. Dusty sandy loams and light silty loams form fragile lumps that easily disintegrate when crushed with fingers. When rubbed, sandy loam produces a rustling sound and falls off the hand. When rubbing light loam with your fingers, a clearly visible roughness is felt, clay particles are rubbed into the skin. Medium silty loams give a feeling of mealiness, but carry the feeling of fine flour with a barely noticeable roughness. Their lumps are crushed with some effort. Heavy silty loams in a dry state are difficult to crush and give the feeling of fine flour when rubbed. Roughness is not felt.

Now, having received the test results, you can relatively accurately determine when and how much to add, you can, so to speak, “loam” your clay. Organic fertilizers, first of all, for crops with low organic requirements on relatively light loamy soils, should be applied in smaller volumes (about 4 kg/m2), but more often, and vice versa, the properties of heavy soils allow manure to be applied less frequently, but in higher quantities (up to 8 kg/m2). The mechanical composition of the soil on the site must be taken into account when adjusting the depth of their embedding.

Alexander Zharavin, agronomist,
Kirov
Based on materials from Flora Price

Table of soil classification by groups

Both the service life of the building and the level of “quality of life” of its residents depend on the reliability of the functioning of the “foundation-foundation-structure” system. Moreover, the reliability of this system is based precisely on the characteristics of the soil, because any structure must rest on a reliable foundation.

That is why the success of most undertakings of construction companies depends on the competent choice of the location of the construction site. And such a choice, in turn, is impossible without understanding the principles on which the classification of soils is based.

From the point of view of construction technologies, there are four main classes, which include:

Rocky soils, the structure of which is homogeneous and based on rigid crystalline bonds;
- dispersed soils consisting of unconnected mineral particles;
- natural, frozen soils, the structure of which was formed naturally, under the influence of low temperatures;
- technogenic soils, the structure of which was formed artificially as a result of human activity.

However, such a classification of soils is somewhat simplified and only shows the degree of homogeneity of the base. Based on this, any rocky soil is a monolithic foundation consisting of dense rocks. In turn, any non-rocky soil is based on a mixture of mineral and organic particles with water and air.

Of course, in the construction business there is little benefit from such a classification. Therefore, each type of base is divided into several classes, groups, types and varieties. Such a classification of soils into groups and varieties makes it easy to navigate the expected characteristics of the future foundation and makes it possible to use this knowledge in the process of building a house.

For example, belonging to one or another group in the classification of soils is determined by the nature of the structural connections that affect the strength characteristics of the foundation. And the specific type of soil indicates the material composition of the soil. Moreover, each classification variety indicates a specific ratio of the components of the material composition.

Thus, a deep classification of soils into groups and varieties gives a completely personalized idea of ​​all the advantages and disadvantages of the future construction site.

For example, in the most common class of dispersed soils in the European part of Russia, there are only two groups dividing this classification into coherent and non-cohesive soils. In addition, special silty soils are included in a separate subgroup of the dispersed class.

This classification of soils means that among dispersed soils there are groups with both pronounced connections in the structure and the absence of such connections. The first group of cohesive dispersed soils includes clayey, silty and peaty soil types. Further classification of dispersed soils allows us to distinguish a group with a non-cohesive structure - sands and coarse soils.

In practical terms, such a classification of soils into groups allows us to get an idea of ​​the physical characteristics of the soil “without regard” to a specific type of soil. Dispersed cohesive soils have practically the same characteristics such as natural humidity (varies within 20%), bulk density (about 1.5 tons per cubic meter), loosening coefficient (from 1.2 to 1.3), particle size (about 0.005 millimeter) and even the plasticity number.

Similar coincidences are also typical for dispersed non-cohesive soils. That is, having an idea of ​​the properties of one type of soil, we obtain information about the characteristics of all types of soil from a specific group, which allows us to introduce averaged schemes into the design process that facilitate strength calculations.

In addition, in addition to the above schemes, there is a special classification of soils according to the difficulty of development. This classification is based on the level of “resistance” of the soil to mechanical stress from earth-moving equipment.

Moreover, the classification of soils according to the difficulty of development depends on the specific type of equipment and divides all types of soils into 7 main groups, which include dispersed, cohesive and non-cohesive soils (groups 1-5) and rocky soils (groups 6-7).

Sand, loam and clay soils (belonging to groups 1-4) are developed using conventional excavators and bulldozers. But the remaining participants in the classification require a more decisive approach based on mechanical loosening or blasting. As a result, we can say that the classification of soils according to the difficulty of development depends on such characteristics as adhesion, loosening and density of the soil.

GENETIC TYPES OF SOILS OF THE QUATERNARY AGE

Soil types	Designation
Alluvial (river sediments)	a
Ozernye	l
Lacustrine-alluvial	la
Deluvial (deposits of rain and melt water on slopes and at the foot of hills)	d
Alluvial-deluvial	ad
Aeolian (deposition from air): aeolian sands, loess soils	L
Glacial (glacial deposits)	g
Fluvioglacial (deposition of glacial streams)	f
Lacustrine-glacial	lg
Eluvial (rock weathering products remaining at the site of formation)	e
Eluvial-deluvial	ed
Proluvial (deposits of stormy rain flows in mountainous areas)	p
Alluvial-proluvial	ap
Marine	m

CALCULATION FORMULAS FOR THE BASIC PHYSICAL CHARACTERISTICS OF SOILS

PARTICLE DENSITY ρs SANDY AND silty-clayey soils

CLASSIFICATION OF ROCK SOILS

Priming	Index
According to the ultimate uniaxial compressive strength in a water-saturated state, MPa
Very durable	Rc > 120
Lasting	120 ≥ Rc > 50
Medium strength	50 ≥ Rc > 15
Low strength	15 ≥ Rc > 5
Reduced strength	5 ≥ Rc > 3
Low strength	3 ≥ Rc ≥ 1
Very low strength	Rc < 1
According to the softening coefficient in water
Non-softening	K saf ≥ 0,75
Softenable	K saf < 0,75
According to the degree of solubility in water (sedimentary cemented), g/l
Insoluble	Solubility less than 0.01
Sparingly soluble	Solubility 0.01-1
Moderately soluble	− || − 1—10
Easily soluble	− || − more than 10

CLASSIFICATION OF COARSE CLASSIC AND SANDY SOILS ACCORDING TO GRANULOMETRIC COMPOSITION

DIVISION OF COARSE CLASTIC AND SANDY SOILS ACCORDING TO DEGREE OF HUMIDITY Sr

DIVISION OF SANDY SOILS ACCORDING TO DENSITY

Sand	Subdivision by density
	dense	medium density	loose
By porosity coefficient
Gravelly, large and medium-sized	e < 0,55	0,55 ≤ e ≤ 0,7	e > 0,7
Small	e < 0,6	0,6 ≤ e ≤ 0,75	e > 0,75
Dusty	e < 0,6	0,6 ≤ e ≤ 0,8	e > 0,8
According to soil resistivity, MPa, under the tip (cone) of the probe during static probing
	q c > 15	15 ≥ q c ≥ 5	q c < 5
Fine regardless of humidity	q c > 12	12 ≥ q c ≥ 4	q c < 4
Dusty: low-moisture and humid water-saturated	q c > 10 q c > 7	10 ≥ q c ≥ 3 7 ≥ q c ≥ 2	q c < 3 q c < 2
According to the conditional dynamic resistance of the soil MPa, probe immersion during dynamic sounding
Large and medium size, regardless of humidity	qd > 12,5	12,5 ≥ qd ≥ 3,5	qd < 3,5
Small: low-moisture and humid water-saturated	qd > 11 qd > 8,5	11 ≥ qd ≥ 3 8,5 ≥ qd ≥ 2	qd < 3 qd < 2
Dusty, low-moisture and humid	qd > 8,8	8,5 ≥ qd ≥ 2	qd < 2

DIVISION OF silty-clayey SOILS ACCORDING TO PLASTICITY NUMBER

DIVISION OF DULLY-CLAY SOILS ACCORDING TO FLUIDITY INDICATOR

DIVISION OF SLUD BY POROSITY COEFFICIENT

DIVISION OF SAPROPELS ACCORDING TO RELATIVE CONTENT OF ORGANIC MATTER

STANDARD VALUES OF DEFORMATION MODULES E silty-clayey soils

Age and origin of soils	Priming	Turnover rate	Values E, MPa, at porosity coefficient e
			0,35	0,45	0,55	0,65	0,75	0,85	0,95	1,05	1,2	1,4	1,6
Quaternary sediments: illuvial, deluvial, lacustrine-alluvial	Sandy loam	0 ≤ I L ≤ 0,75	-	32	24	16	10	7	-	-	-	-	-
	Loam	0 ≤ I L ≤ 0,25	-	34	27	22	17	14	11	-	-	-	-
		0,25 < I L≤ 0,5	-	32	25	19	14	11	8	-	-	-	-
		0,5 < I L ≤ 0,75	-	-	-	17	12	8	6	5	-	-	-
	Clay	0 ≤ I L≤ 0,25	-	-	28	24	21	18	15	12	-	-	-
		0,25 < I L ≤ 0,5	-	-	-	21	18	15	12	9	-	-	-
		0,5 < I L ≤ 0,75	-	-	-	-	15	12	9	7	-	-	-
fluvioglacial	Sandy loam	0 ≤ I L ≤ 0,75	-	33	24	17	11	7	-	-	-	-	-
	Loam	0 ≤I L ≤ 0,25	-	40	33	27	21	-	-	-	-	-	-
		0,25<I L≤0,5	-	35	28	22	17	14	-	-	-	-	-
		0,5 <I L ≤ 0,75	-	-	-	17	13	10	7	-	-	-	-
moraine	Sandy loam and loam	I L ≤ 0,5	75	55	45	-	-	-	-	-	-	-	-
Jurassic deposits of the Oxfordian stage	Clay	− 0,25 ≤I L ≤ 0	-	-	-	-	-	-	27	25	22	-	-
		0 < I L ≤ 0,25	-	-	-	-	-	-	24	22	19	15	-
		0,25 < I L ≤ 0,5	-	-	-	-	-	-	-	-	16	12	10

Determination of deformation modulus in the field

The deformation modulus is determined by testing the soil with a static load transmitted to the stamp. Tests are carried out in pits with a rigid round stamp with an area of ​​5000 cm2, and below the groundwater level and at great depths - in wells with a stamp with an area of ​​600 cm2.

Dependence of die draft s from pressure R

1 — rubber chamber; 2 - well; 3 - hose; 4 - compressed air cylinder: 5 - measuring device

Dependence of borehole wall deformations Δ r from pressure R

To determine the deformation modulus, use a graph of the dependence of settlement on pressure, in which a linear section is identified, an averaging line is drawn through it, and the deformation modulus is calculated E in accordance with the theory of linearly deformable medium according to the formula

E = (1 − ν 2)ωdΔ p / Δ s

Where v- Poisson's ratio (transverse deformation coefficient), equal to 0.27 for coarse soils, 0.30 for sands and sandy loams, 0.35 for loams and 0.42 for clays; ω — dimensionless coefficient equal to 0.79; d p is the increment of pressure on the stamp; Δ s— increment of die draft corresponding to Δ R.

When testing soils, it is necessary that the thickness of the layer of homogeneous soil under the stamp be at least twice the diameter of the stamp.

The deformation moduli of isotropic soils can be determined in boreholes using a pressuremeter. As a result of the tests, a graph of the dependence of the increase in the radius of the well on the pressure on its walls is obtained. The deformation modulus is determined in the section of the linear dependence of deformation on pressure between the point R 1, corresponding to the compression of uneven walls of the well, and the point R 2 E = kr 0 Δ p / Δ r

Where k- coefficient; r 0 — initial radius of the well; Δ R— pressure increment; Δ r— radius increment corresponding to Δ R.

Coefficient k determined, as a rule, by comparing pressureometry data with the results of parallel tests of the same soil with a stamp. For buildings of class II and III, it is allowed to take depending on the test depth h the following coefficient values k in the formula: when h < 5 м k= 3; at 5m ≤ h≤ 10 m k h ≤ 20 m k = 1,5.

For sandy and silty clay soils, it is possible to determine the deformation modulus based on the results of static and dynamic sounding of soils. The following are taken as sounding indicators: for static sounding - soil resistance to immersion of the probe cone q c, and during dynamic sounding - the conditional dynamic resistance of the soil to immersion of the cone qd. For loams and clays E = 7q c And E = 6qd; for sandy soils E = 3q c, and the values E according to dynamic sounding data are given in the table. For class I and II structures, it is mandatory to compare sounding data with the results of testing the same soils with stamps.

VALUES OF DEFORMATION MODULES E OF SANDY SOILS ACCORDING TO DYNAMIC PROBING DATA

For Class III structures it is allowed to determine E only based on sounding results.

Determination of deformation modulus in laboratory conditions

In laboratory conditions, compression devices (odometers) are used, in which a soil sample is compressed without the possibility of lateral expansion. The deformation modulus is calculated over the selected pressure range Δ R = p 2 − p 1 test schedule (Fig. 1.4) according to the formula

E oed = (1 + e 0)β / a
Where e 0—initial soil porosity coefficient; β — coefficient that takes into account the absence of lateral expansion of the soil in the device and is assigned depending on the Poisson’s ratio v; A— compaction coefficient;
a = (e 1 − e 2)/(p 2 − p 1)

AVERAGE POISSON'S RATIO VALUES vβ

ODDS m FOR ALLUVIAL, DELUVIAL, LACUSCINE AND LACUSCINE-ALLUVIAL QUATERNARY SOILS WITH FLUIDITY INDICATOR I L ≤ 0,75

STANDARD SPECIFIC GRIP VALUES c φ , hail, SANDY SOILS

Sand	Characteristic	Values With And φ at porosity coefficient e
		0,45	0,55	0,65	0,75
Gravelly and large	With φ	2 43	1 40	0 38	- -
Medium size	With φ	3 40	2 38	1 35	- -
Small	With φ	6 38	4 36	2 32	0 28
Dusty	With φ	8 36	6 34	4 30	2 26

STANDARD VALUES FOR SPECIFIC GRIP c, kPa, AND INTERNAL FRICTION ANGLES φ , hail, silty-clayey soils of Quaternary deposits

Priming	Turnover rate	Characteristic	Values With And φ at porosity coefficient e
			0,45	0,55	0,65	0,75	0,85	0,95	1,05
Sandy loam	0<I L≤0,25	With φ	21 30	17 29	15 27	13 24	- -	- -	- -
	0,25<I L≤0,75	With φ	19 28	15 26	13 24	11 21	9 18	- -	- -
Loam	0<I L≤0,25	With φ	47 26	37 25	31 24	25 23	22 22	19 20	- -
	0,25<I L≤0,5	With φ	39 24	34 23	28 22	23 21	18 19	15 17	- -
	0,5<I L≤0,75	With φ	- -	- -	25 19	20 18	16 16	14 14	12 12
Clay	0<I L≤0,25	With φ	- -	81 21	68 20	54 19	47 18	41 16	36 14
	0,25<I L≤0,5	With φ	- -	- -	57 18	50 17	43 16	37 14	32 11
	0,5<I L≤0,75	With φ	- -	- -	45 15	41 14	36 12	33 10	29 7

VALUES OF INTERNAL FRICTION ANGLES φ SANDY SOILS ACCORDING TO DYNAMIC PROBING DATA

ESTIMATED VALUES OF SOIL FILTRATION COEFFICIENT

STATISTICAL CRITERION VALUES

Number definitions	v		Number definitions	v		Number definitions	v
6	2,07		13	2,56		20	2,78
7	2,18		14	2,60		25	2,88
8	2,27		15	2,64		30	2,96
9	2,35		16	2,67		35	3,02
10	2,41		17	2,70		40	3,07
11	2,47		18	2,73		45	3,12
12	2,52		19	2,75		50	3,16

TABLE 1.22. COEFFICIENT VALUES t α WITH ONE-SIDED CONFIDENCE α

Number definitions n−1 or n−2	t α at α			Number definitions n−1 or n−2	t α at α
	0,85	0,95			0,85	0,95
2	1,34	2,92		13	1,08	1,77
3	1,26	2,35		14	1,08	1,76
4	1,19	2,13		15	1,07	1,75
5	1,16	2,01		16	1,07	1,76
6	1,13	1,94		17	1,07	1,74
7	1,12	1,90		18	1,07	1,73
8	1,11	1,86		19	1,07	1,73
9	1,10	1,83		20	1,06	1,72
10	1,10	1,81		30	1,05	1,70
11	1,09	1,80		40	1,06	1,68
12	1,08	1,78		60	1,05	1,67