The angles of repose of soils and the ratio of the height of the slope to the foundation. Determination of the angle of repose of sandy soil What is the angle of repose of the soil

Angle of repose or rest angle - this is the angle between the plane of the base of the stack and the generatrix, which depends on the type and condition of the cargo. Angle of repose is the maximum slope angle of granular non-cohesive material, i.e. free-flowing material. Loose and porous bulk cargoes have a greater angle of rest than solid lump cargoes. With increasing humidity, the angle of rest increases. During long-term storage of many bulk cargoes, the angle of rest increases due to compaction and caking. Distinguish between the angle of repose at rest and in motion. At rest, the angle of repose is 10–18° greater than in motion (for example, on a conveyor belt).

The value of the angle of repose of the load depends on the shape, size, roughness and uniformity of the load

particles, humidity of the mass of the cargo, method of its dumping, initial state and material of the supporting surface.

Various methods are used to determine the magnitude of the angle of repose; the most common methods are filling and caving.

The experimental determination of the shear resistance and the main parameters of the load is usually carried out by the methods of direct shear, uniaxial and triaxial compression. Tests of cargo properties by direct shear methods are applicable to both ideal and cohesive bulk solids. The test method for uniaxial (simple) compression - crushing is applicable only to assess the total shear resistance of cohesive granular bodies under the conditional assumption that a uniform stress state is maintained at all points of the test sample. The most reliable results of testing the characteristics of a cohesive granular body are obtained by the triaxial compression method, which makes it possible to investigate the strength of a load sample under all-round compression.

Determination of the angle of repose of fine-grained substances (particle sizes less than 10 mm) is carried out using a "tilted box". The angle of repose in this case is the angle formed by the horizontal plane and the upper edge of the test box at the moment when mass shedding of the substance in the box begins.

The ship method for determining the angle of repose of a substance is used in the absence of a "tilt box"

ka". In this case, the angle of repose is the angle between the generatrix of the load cone and the horizontal

plane.

Angle of repose. Methods for determination in natural conditions

Angle of repose or rest angle - e then the angle between the plane of the base of the stack and the generatrix, which depends on the type and condition of the cargo. The angle of repose is the maximum slope angle of non-cohesive granular material, i.e. free-flowing material.

In practice, data on angle of repose are used in determining the area of ​​cargo stacking, the amount of cargo in the stack, the volume of intra-hold stowage work, when calculating the pressure of the cargo on the walls enclosing it

Various methods are used to determine the magnitude of the angle of repose; The most common methods are embankments and collapse.

Experimental definition shear resistance and the main parameters of the cargo is usually produced by methods straight cut, uniaxial and triaxial compression.

Determining the angle of repose fine-grained substances(particle sizes less than 10 mm) is produced using " inclined box". The angle of repose in this case is the angle formed by the horizontal plane and the upper edge of the test box at the moment when mass shedding of the substance in the box begins.

ship method determination of the angle of repose of a substance is used in the absence of a "tilt box". In this case, the angle of repose is the angle between the generatrix of the load cone and the horizontal plane.

The practice of measuring the angles of repose in natural conditions shows that their value is somewhat changes depending on the dumping method cargo (jet or rain), masses investigated cargo, heights, with which experimental filling is performed.

Convenient for quick measurements Mohs method, in which the grain is poured into a rectangular box with glass walls measuring 100x200x300 mm for 1/3 of its height. The box is carefully rotated 90° and the angle between the surface of the grain and the horizontal (after rotation) wall is measured.

Angle of repose- this is the largest angle that can be formed by a slope of freely poured soil in equilibrium with a horizontal plane.

The angle of repose depends on particle size distribution and particle shape. As the grain size decreases, the angle of repose becomes flatter.
In the air-dry state, the angle of repose of sandy soil is 30-40°, under water - 24-33°. For non-cohesive (loose) soils, the angle of repose does not exceed the angle of internal friction

To determine the angle of repose of sandy soil in an air-dry state, the UVT device is used ( rice. 9.11, 9.12), under water - VIA ( rice. 9.13).

According to rice. 9.12 when the box is tilted, the sand crumbles and, loosening, forms a slope with an angle that can be determined by a protractor or by the formula

The concept of angle of repose applies only to dry loose soils, and for cohesive clay soils it loses all meaning, since in the latter it depends on moisture content, slope height and slope load and can vary from 0 to 90 °.

Rice. 9.11. UVT-2 device: 1 - scale; 2 - tank; 3 - measuring table; 4 - clip; 5 - support; 6 - sand sample

Rice. 9.12. Determining the angle of repose by rotating the container (a) and slowly removing the plate (b): A - axis of rotation of the container

Rice. 9.13. VIA device: 1 - VIA box; 2 - sand sample; 3 - container with water; 4 - protractor; 5 - axis of rotation; 6- piezometer; 7- tripod

During the development and shrinkage of the loosened soil cuts and embankments form natural slopes of various steepness. The greatest steepness of flat slopes of earthworks, trenches and pits, arranged without fasteners, should be taken according to tab. 9.2. When ensuring the natural steepness of the slopes, the stability of earthen embankments and excavations is ensured.

Table 9.2. The greatest steepness of slopes of trenches and pits, hail.

The slopes of embankments of permanent structures are performed more gentle than the slopes of excavations.

General provisions

Purpose and types of earthworks

The volume of earthworks is very large, it is available during the construction of any building and structure. Earthworks account for 10% of the total labor intensity in construction.

The following main types of earthworks are distinguished:

Site layout;

Pit and trenches;

Roadbeds;

Dams;

Channels, etc.

Earthworks are divided into:

Permanent;

Temporary.

Constants include pits, trenches, embankments, excavations.

Requirements for permanent earthworks:

Must be durable, i.e. resist temporary and permanent loads;

sustainable;

Good resistance to atmospheric influences;

Good resistance to erosive action;

Must be infallible.

Basic building properties and soil classification

The soil is called the rocks occurring in the upper layers of the earth's crust. These include: vegetable soil, sand, sandy loam, gravel, clay, loess-like loam, peat, various rocky soils and quicksand.

According to the size of mineral particles and their interconnection, the following soils are distinguished :

Connected - clay;

Non-cohesive - sandy and loose (in a dry state), coarse-grained non-cemented soils containing more than 50% (by weight) of fragments of crystalline rocks larger than 2 mm;

Rocky - igneous, metamorphic and sedimentary rocks with a rigid connection between the grains.

The main properties of soils that affect the production technology, labor intensity and cost of earthworks include:

Bulk weight;

Humidity;

Blurring

Clutch;

looseness;

Angle of repose;

Volumetric mass is the mass of 1 m3 of soil in its natural state in a dense body.

The bulk density of sandy and clay soils is 1.5 - 2 t/m3, rocky soils are not loosened up to 3 t/m3.

Humidity - the degree of saturation of the soil pores with water

g b - g c - soil mass before and after drying.

At humidity up to 5% - soils are called dry. With a moisture content of 5 to 15%, soils are called low-moisture. At humidity from 15 to 30% - soils are called wet.
With a moisture content of more than 30%, the soils are called wet.

Cohesion is the initial resistance of the soil to shear.

Soil adhesion force: - sandy soils 0.03 - 0.05 MPa - clayey soils 0.05 - 0.3 MPa - semi-rocky soils 0.3 - 4 MPa - rocky soils more than 4 MPa.

In frozen soils, the adhesion force is much greater.

Looseness- this is the ability of the soil to increase in volume during development, due to the loss of communication between the particles. The increase in soil volume is characterized by the coefficient of loosening K p. After compaction of the loosened soil is called the residual loosening K op.

Angle of repose characterized by the physical properties of the soil. The value of the angle of repose depends on the angle of internal friction, the adhesion force and the pressure of the overlying layers. In the absence of adhesion forces, the limiting angle of repose is equal to the angle of internal friction. The steepness of the slope depends on the angle of repose. The steepness of the slopes of cuts and embankments is characterized by the ratio of height to foundation m is the slope factor.

Angles of repose of soils and the ratio of slope height to foundation

Soil erosion– entrainment of particles by flowing water. For fine sands, the highest water velocity should not exceed 0.5-0.6 m/s, for coarse sands 1-2 m/s, for clay soils 1.5 m/s.

Angle of repose

Angle of repose

Angle of repose- the angle formed by the free surface of loose rock mass or other bulk material with a horizontal plane. Sometimes the term "angle of internal friction" may be used.

Particles of material located on the free surface of the embankment experience a state of critical (limiting) equilibrium. The angle of repose is related to the coefficient of friction and depends on the roughness of the grains, the degree of their moisture, particle size distribution and shape, as well as on specific gravity material.

The angles of repose are determined by the maximum allowable angles slopes of ledges and sides of quarries, embankments, dumps and piles. angle of repose various materials

List of various materials and their angle of repose. The data is approximate.

see also

Notes

Wikimedia Foundation. 2010 .

See what the "Angle of repose" is in other dictionaries:

angle of repose- The limiting angle formed by the free slope of loose soil with a horizontal plane, at which there is no violation of the stable state [Terminological dictionary for construction in 12 languages ​​(VNIIIS Gosstroy of the USSR)] angle ... ... Technical Translator's Handbook

The maximum angle of inclination of the slope, folded by the gp, at which they are in balance, i.e., they do not crumble, do not creep. Depends on the composition and condition of the settlements that make up the slope, their water content, and for clayey settlements, the height of the slope. Geological … Geological Encyclopedia

Angle of (natural) repose- (Böschungswinkel) - the angle relative to the horizontal, formed when bulk material is poured. [STB EN1991 1 1 20071.4] Term heading: General, placeholders Encyclopedia headings: Abrasive equipment, Abrasives, Roads … Encyclopedia of terms, definitions and explanations of building materials

angle of repose- The ultimate steepness of the slope, at which the loose deposits composing it are in equilibrium (do not crumble). Syn.: natural slope… Geography Dictionary

angle of repose- 3.25 angle of repose formed by generatrix slope with a horizontal surface when dumping loose material (soil) and close to the value of its angle of internal friction. Source … Dictionary-reference book of terms of normative and technical documentation

ANGLE OF REVERSE- the angle at which the unreinforced slope of sandy soil still maintains balance, or the angle at which freely poured sand is located. U.e.o. determined in air-dry state and under water ... Dictionary of hydrogeology and engineering geology

angle of repose- the angle at the base of the cone, formed during the free pouring of bulk material on a horizontal plane; characterizes the flowability of this material; See also: Angle contact angle contact angle … Encyclopedic Dictionary of Metallurgy

The limiting angle formed by a free slope of loose soil with a horizontal plane, at which there is no violation of the stable state (Bulgarian; Български) ъгъл on a natural slope (Czech; Čeština) úhel přirozeného… … Construction dictionary

Ecological dictionary

SOIL SLOPE- (soil) the largest possible angle that a stable slope of an embankment of dry soil (soil), or wet soil (soil) under water, forms with a horizontal surface. Ecological Dictionary, 2001 The angle of repose of the soil (soil) ... ... Ecological dictionary

REPUBLICAN BUILDING REGULATIONS

ENGINEERING SURVEYS FOR CONSTRUCTION.
PRODUCTION OF LABORATORY STUDIES
PHYSICAL AND MECHANICAL PROPERTIES OF SOILS

RSN 51-84

Gosstroy of the RSFSR

STATE COMMITTEE OF THE RSFSR ON AFFAIRS
CONSTRUCTION

Developed by the trusts of engineering and construction surveys MosTsTISIZ, UralTISIZ, TulaTISIZ of the Production Association for Engineering and Construction Surveys (“Stroyizyskaniya”) of the Gosstroy of the RSFSR.

Performers: I.N. Shishelov, Ph.D. those. Sciences Yu.V. Syrokomsky, I.B. Kogos, T.D. Beloglazova, R.A. Menshikov, L.I. Podkorytova, A.S. Romanova.

Submitted and prepared for approval by the Production Association for Engineering and Construction Surveys (“Stroyizyskaniya”) of the Gosstroy of the RSFSR.

Entered for the first time.

These Republican building codes apply to organizations that perform soil surveys during engineering surveys for the construction of industrial, residential and agricultural facilities and establish the basic requirements for the production of laboratory studies of the physical and mechanical properties of soils.

1. GENERAL PROVISIONS

1.1. Laboratory studies of soils should be carried out in accordance with the requirements state standards, building codes and regulations, as well as these Republican building codes.

1.2. The composition of laboratory studies of soils should be established in accordance with the requirements of the current regulatory documents and programs for the production of survey work.

1.3. Laboratory studies of soils should be carried out using progressive methods, modern instruments and equipment that provide high quality soil testing, the highest labor productivity and a reduction in the duration of laboratory work.

1.4. In the production of laboratory studies of soils, measures should be taken to save materials and electricity, as well as to ensure careful attitude to equipment, instruments, tools and inventory.

1.5. The cost of laboratory work is determined according to the Collection of prices for survey work for capital construction.

1.6. In the production of laboratory work, it is necessary to comply with the requirements provided for by the rules and instructions for labor protection and safety.

2. ORGANIZATION OF LABORATORY WORKS

2.1. Laboratory works should be carried out in accordance with the schedule and tasks for their implementation.

The schedule is drawn up by the head of the laboratory and agreed with the head of the engineering and geological production units - customers of laboratory soil tests.

ass ani e for laboratory and soil investigations is drawn up customer department these x works. The task must be signed by the head of the division and the chief geologist m of production subdivision-customer.

2.2. The quality control of laboratory studies of soils - input, operational, acceptance - should be carried out in accordance with the standard of the enterprise of an integrated system for managing the quality of engineering surveys in construction (K SUKIIS) at all stages of work.

The input control should be subjected to soil samples arriving for research, customer assignments, newly received equipment, devices, and tools. Input control should be continuous and carried out by the head of the laboratory and or a specially authorized employee.

Operation and onc control should be carried out in the process of laboratory testing of soils and maintaining primary documentation. The following working processes are subject to special control: taking an average sample, cutting out soil samples, maintaining the temperature at a certain humidity, periodically calibrating the hydrometer when determining granulometric composition, calculation of loads in determining the shear resistance y.

Op Rational control of instruments should be carried out in accordance with the requirements. The performers of the work must carry out continuous operational control (self-control), the head of the laboratory or and a specially authorized worker - selective.

At An important control should be subjected to the results of laboratory studies of soils prepared for transfer to the customer. Acceptance control should be complete and carried out head of the laboratory.

2.3. Re the results of laboratory and soil studies are issued to customers in the form machine-oriented statements when processing data on a computer or in the form of statements of passports of results and soil investigations.

2.4. Inform the head of the laboratory immediately transfers the notification about deviations from the standards during laboratory research of soils to the customer of laboratory work.

3. EQUIPMENT, INSTRUMENTS, PREMISES

3. 1. Laboratory and research of soils should be provided with equipment, instruments, tools and inventory in accordance with the Tables of equipment from prospecting and design and survey organizations devices, equipment m, vehicles, camp equipment and means of communication.

3.2. For the metrological support of the production of laboratory studies of the physical and mechanical properties of soils, the equipment and instruments of the soil laboratory must be checked within the established time limits in accordance with the requirements of GOST 8.002-71 and the standards of the KSUKIIS enterprise.

3.3. To ensure the constant operational readiness of equipment and instruments, the system should be used on a planned basis. - precautionary repairs, providing for complex precautionary measures aimed at eliminating progressive out of wasps.

3. 4. Maintenance, providing supervision, maintenance, checking the condition of equipment and instruments, for except for electrical equipment should be carried out co according to d to the new schedule by the staff py new laboratories - preparators, laboratory assistants, technicians, engineers.

3 .5. The current repair of equipment and instruments, which involves the replacement or restoration of parts and assemblies, troubleshooting operations, and maintenance of electrical equipment should be carried out by the mechanical repair service from the survey organization.

3.6. In the premises of the research laboratory soil equipment should be grouped based on the need for it joint work, as well as according to the principle of the same effect on environment(emission of dust, heat, vapors; noise, etc.) and environmental influences (vibration, temperature, humidity).

3.7. The composition of the premises of the laboratory and the study of soils is established depending on the composition, properties, and condition of the soils; composition and quantity of equipment. The minimum and maximum compositions of rooms are given in .

3.6. The sequence of location of the premises is established according to the routes of soil movement according to the analyzes.

3.9. The area of ​​the premises is set depending on the composition and quantity of equipment, the size of the passages between the equipment, the number of employees.

3.10. Special requirements for the layout of soil laboratories are given in.

3.11. Special requirements for water supply, sewerage, ventilation, power supply of the soil research laboratory are given in.

4. STORAGE, TRANSPORTATION AND PREPARATION FOR ANALYSIS OF SOIL SAMPLES

4.1. Receipt and storage soil samples in the laboratory soil studies should be carried out in accordance with with the requirements of GOST 12071-72.

To the subdivision-customer With le blowing d leave and lay out and the shelves of the laboratory storing the samples in the order in which they were included in the task.

H head of the lab oratory or specially authorized employee in in the presence of a geologist leading the object, the safety of the samples should be checked, no mechanical damage packaging, sufficiency and suitability of samples for production, provided for by setting the composition of the definitions.

4.2. Horizontal transport soil in the laboratory should be carried out with the help of manual transport carts, vertical - freight elevators or special lifts.

4.3. Study physical and mechanical soil properties when opened ii samples should be start with a visual examination and description of the samples. Description must contain information about the composition , lithological especially nn ostya x and condition of the samples.

4.4. Cutting samples and preparing soils for analyzes should be done usually by means of machinery.

5. SOIL INVESTIGATION METHODS

5.1. Soil classification should be carry out in accordance with the requirements of GOST 25100-82.

5.2. Granulometric and microaggregate composition should determine in accordance with the requirements of GOST 12536-79. Screening soils should be produced with the help of mechanical s and t, shaking - with the help of a mechanical shaker.

5.3 . Density should be determined in accordance with the requirements of GOST 5180 - 75.

5.4. Soil density should be determined in accordance with the requirements of GOST 5182-78. The density of soil in a loose and dense state should be determined in accordance with the requirements.

5.5. The density of soil particles should be determined in accordance with the requirements of GOST 5181-78.

5.6. The density of rock particles should be determined in accordance with the requirements.

5.7. The boundaries of yield and rolling should be determined in accordance with the requirements of GOST 5183-77.

5.8. When determining the yield limit, mechanized methods of lowering the cone (without additional effort) and automated methods of counting the time intervals of the experiment should be used.

5.9. The maximum molecular moisture capacity should be determined in accordance with the requirements.

5.10. Swelling and shrinkage characteristics should be determined in accordance with the requirements of GOST 24143-80.

5.11. Soakability should be determined in accordance with the requirements.

5.12. Settling characteristics should be determined in accordance with the requirements of GOST 23161-78.

5.13. Specific penetration resistance, should be determined in accordance with the requirements.

5.14. The maximum density should be determined in accordance with the requirements of GOST 22733-77. A mechanized method of lifting the load and an automated method of turning off the device after a cycle of impacts should be used.

The angle of repose should be determined in accordance with the requirements.

The filtration coefficient should be determined in accordance with the requirements of GOST 25584 -83. Automated methods should be used to count the time of lowering the liquid by a given value.

5.17. Suffusion compressibility should be determined according to GOST 25585-83.

5.18. Compressibility should be determined in accordance with the requirements of GOST 23908-79.

5.19. The compressibility of eluvial soils should be determined in accordance with the requirements.

5.20. Shear resistance should be determined in accordance with the requirements of GOST 12248-78. In devices with a constant shear rate, mechanized devices for moving the carriage and automated means of fixing the maximum force of the dynamometer in the sample deformation area of ​​0-5 mm and turning off the device when a deformation of 5 mm is reached should be used.

5.21. The tensile strength of rocky soils from reduced to very low strength in uniaxial compression of samples of regular shape should be determined in accordance with the requirements of GOST 17245-79.

5.22. The tensile strength of rocky soils from very strong to low strength in uniaxial compression of samples of the correct company should be determined in accordance with the requirements of GOST 21153.0-75 * and GOST 21153.2 -75.

5.23. The ultimate strength of rocky soil samples of arbitrary shape should be determined in accordance with the requirements of GOST 21941-81.

5.24. The weathering coefficient should be determined in accordance with the requirements.

5.25. Corrosive activity should be determined in accordance with the requirements of GOST 9.015-74.

5 .26. The relative content of plant residues and the degree of decomposition of peaty soils should be determined in accordance with with requirements GOST 23740-79.

6. LABORATORY DOCUMENTATION

6.1. Working Journals, output sheets, passports and other laboratory documents should be drawn up in accordance with the requirements state standards and "Guidelines for the preparation and execution of engineering survey documentation for construction".

6.2. Ter Mines and definitions used in laboratory documentation must correspond to those given in the state standard.

6.3. Unit The units of physical quantities, the name and designation of these units, used in laboratory documentation, must correspond to the units given in GOST 8.417-81 and in CH 528-80.

OPERATIONAL CONTROL OF DEVICES

This control procedure applies to: balancer cone, sieves, scales, compression and shear devices, pre-compaction devices. The general requirement of control is an external inspection. Establish the absence of bends, dents, notches, soil particles on the parts of the devices. Control is divided into daily and quarterly. For each device, in the first subparagraph of this methodology, the requirements for shift control are given, in the second - quarterly. Devices that do not meet the requirements of the methodology are not allowed to be used.

1. Balance cone

The tip of the cone must not be blunt.

Measure with a depth gauge (caliper) the distance from the top to the base of the cone (25 mm) with an accuracy of 0.1 mm. Check the readings with those obtained when the cone was put into operation. The discrepancy between readings should not exceed 0.2 mm. The cone must be firmly connected to the arc, the arc - to the weights.

2. Sieves for screening soils

View the sieve grids for light. Nets should not have weaving disturbances, displacement and breakage of wires, breaks in the places of attachment to the body.

View under a microscope with a forty-fold increase in a sieve No. 0.1; 0.25; 0.5 in five places along the sieve radius. Holes should be square in shape. Determine the size of the holes using the Huigen scale. The results should not differ from the nominal by more than 20%.

Determine the dimensions 5 holes in sieves No. 1 and 2 along the radius of each sieve. Measure with a vernier caliper five holes along the radius of each sieve No. 5 and 10. The dimensions of the mesh holes should not differ from the nominal ones by more than 10%.

Press the hand successively on the hoop, the disk of drilled sieves, the disk of the bottom. Details when pressed on them should not swing.

3. Quadrant laboratory scales

3.1. Check the position of the air bubble in the balance level. Move the bubble to the center of the reference circle by rotating the balance feet.

Align the zero mark on the scale with the zero mark on the screen. Place a standard weight on the balance pan, the mass of which corresponds to the mass measurement range on the scale. Repeat the operations until the required weighing limit is reached. The difference in readings should not exceed the permissible weighing error.

3.2. Check the clarity of the scale image on the screen, achieve clarity by moving the scale illumination lamp.

4. Compression device

4.1. When preparing the device for the experiment, look at the bottom and the stamp in the light. All openings must allow light to pass through.

The ropes of the compression mechanism must lie in the machined grooves.

3.5. It is allowed to use air-dry soils adjusted for hygroscopic moisture in accordance with GOST 5181-78.

3 .6. Distilled water is boiled for 1 hour and stored in a sealed bottle.

3.7. Make a table of masses of pycnometers with distilled water at various temperatures. The masses of pycnometers with distilled water at different temperatures are calculated according to GOST 5181-78.

4. Conducting a test

Corresponds to GOST 5181-78.

5. Results processing

METHOD OPRE MATTER OF THE MAXIMUM MOLECULAR MOISTURE CAPACITY

infusion The general technique applies to silty clayey and sandy soils and establishes a laboratory method for determining the maximum molecular water capacity.

1. General provisions

1.1. Molecular moisture capacity of the soil - the ability of soil particles to hold one or another amount of water on their surface by molecular attraction.

1.2. The maximum molecular moisture capacity should be defined as the moisture content of the soil paste after pressing it until the completion of soil water loss.

1.3. The maximum molecular moisture capacity of silt-clay soils is determined on samples with natural moisture.

1.4. The determination of the maximum molecular moisture capacity is carried out with two repetitions.

2. Equipment

1.4. Weighing is carried out with accuracy ± 1 g

1.5. Calculation results K vk should have an error of no more than 0.01.

2. Hardware

Shelf drum with a rotation speed of 50-70 rpm.

Sieve with mesh No. 2 in accordance with GOST 3584-73 with a pallet.

Laboratory scales with a weighing limit of 5 kg in accordance with GOST 19491-74.

3. Preparation for testing m

3.1. An average sample weighing 2-2.5 kg is taken, avoiding "round" values ​​of 2 or 2.5 kg.

3.2. The soil is sieved through a No. 2 sieve and divided into fine earth and debris.

3.3. Establish the mass of fine earth t 1 and wreckage t 2 .

4. Testing

4.1. The sample is loaded into a shelf drum.

4.2. The tests are carried out in cycles of rotation of the drum for 2 minutes, each time setting the mass of fine earth by sifting, the ratio of t 1 to t 2 is taken as the natural degree of destruction after a four-minute test in the drum.

4.6. In the case of an increase in the yield of fine earth by more than 25% for To take the value set before the start of the test.

4.7. The obtained values ​​of the masses of fine earth and debris, corresponding to different cycles, are recorded in the journal.

5. Processing of results

5.1. To calculated by the formula ( ).

5.2. The name of coarse-grained soils according to the degree of weathering, depending on K vk is given in table. one.

Table 1

Name of coarse-grained soils according to the degree of weathering