Основы геотехники / Fundamentals of geotechnics

УДК 624.1
ББК 38.58
Ч-91
Рецензенты:
кандидат технических наук, доцент В.Е. Русанов,  
генеральный директор ООО «НИЦ Тоннельной ассоциации»;
доктор технических наук, профессор В.В. Знаменский,  
профессор кафедры механики грунтов и геотехники НИУ МГСУ
 
Чунюк, Дмитрий Юрьевич.
Ч-91	 	
Основы геотехники / Fundamentals of geotechnics [Элек-тронный ресурс] : учебно-методическое пособие / Д.Ю. Чунюк, Н.Г. Лобачева, С.М. Сельвиян ; Мини-стерство науки 
и высшего образования Российской Федерации, Национальный исследовательский Московский государственный строительный университет, кафедра механики грунтов и геотехники. — Электрон. дан. и прогр. (2,5 Мб). — Мос-ква : Издательство МИСИ – МГСУ, 
2024. — URL: http://lib.mgsu.ru. — Загл. с титул. экрана.
ISBN 978-5-7264-3569-5 (сетевое)
ISBN 978-5-7264-3570-1 (локальное)
В учебно-методическом пособии представлены задания, которые выносятся на практические 
занятия, а также присутствуют в вопросах для выполнения контрольной работы и зачета; приведены типовые контрольные вопросы.
Для обучающихся по направлению подготовки 08.03.01 Строительство.
Учебное электронное издание
© ФГБОУ ВО «НИУ МГСУ», 2024

Учебное электронное издание
Чунюк Дмитрий Юрьевич, Лобачева Наталья Геннадиевна, Сельвиян Серафима Михайловна
Основы геотехники /  
Fundamentals of geotechnics
Учебно-методическое пособие
Редактор Н.А. Котова
Корректор В.К. Чупрова
Верстка и дизайн титульного экрана Д.Л. Разумного 
Для создания электронного издания использовано:
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Подписано к использованию 22.10.2024. Объем данных 2,5 Мб.
Федеральное государственное бюджетное образовательное учреждение
высшего образования 
«Национальный исследовательский 
Московский государственный строительный университет».
129337, Москва, Ярославское ш., 26.
Издательство МИСИ – МГСУ. 
Тел.: (495) 287-49-14, вн. 14-23, (499) 183-91-90, (499) 183-97-95.
E-mail: ric@mgsu.ru, rio@mgsu.ru

Оглавление
PRACTICAL LESSON 1....................................................................................................................................5
Example 1.1. Determining the type of sandy soil.........................................................................................8
Example 1.2. Determine the type and variety of coarse sand......................................................................9
Example 1.3. Determine the type and type of clayey soil............................................................................9
Example 1.4. Determine the design resistance of a stiff clay loam..............................................................9
Example 1.5. Determine the design resistance of coarse, medium-density sand saturated  
with water.............................................................................................................................. 10
PRACTICAL LESSON 2.................................................................................................................................. 12
Determination of the deformation characteristics of soils......................................................................... 12
PRACTICAL LESSON 3.................................................................................................................................. 16
Construction of characteristic épure (diagrams) of the distribution of natural stresses  
in a mass of soil..................................................................................................................... 16
Example 3.1. Distribution of stresses from dead-weight of soil in homogeneous massif.......................... 16
Example 3.2. Distribution of stresses from dead weight of soil in the soil mass represented  
by several soil layers............................................................................................................. 18
Example 3.3. Distribution of stresses from self-weight of soil in the soil mass represented  
by several layers of soil, one of which is a water bearing layer............................................ 21
PRACTICAL LESSON 4..................................................................................................................................23
Determination of stresses under the action of local uniformly distributed pressure.................................23
Example 4.1. Determination of the values of compressive stresses σz by the depth of the base................25
Example 4.2. Determination of settlement by the layer-by-layer summation method...............................26
Example 4.3. Determination of foundation settlement by the equivalent layer method............................ 30
Example 4.4. Determination of foundation settlement using the linearly deformable layer method......... 32
PRACTICAL LESSON 5.................................................................................................................................. 35
The active and passive pressures of soil on retaining walls....................................................................... 35
Example 5.1. Determine the value of the active pressure Ea on the wall of height H = 12 m with 
homogeneous soil backfill φ = 31°; γ = 21 kN/m3................................................................ 35
Example 5.2. Calculate the ordinates of the active pressure of the three-layer backfill............................ 36
Example 5.3. Determination the value of active pressure generated by loads applied on the edge 
of the excavation .................................................................................................................. 37
Example 5.4. Calculate the sum of moments from horizontal forces of active ground pressure 
on the enclosing structure (data from examples 5.1 and 5.3)................................................ 38
Example 5.5. Determine the stresses in the wall contact with the base (see fig. 5.2) when 
the base width B = 6 m and the average normal stress σ = 200 kPa..................................... 38
Example 5.6. Determine the ultimate height of the vertical slope of the excavation.  
Soil: sand, angle of internal friction φ = 33°, specific coupling c = 2 kPa,  
specific weight of soil γ = 19,7 kN/m3.................................................................................. 39
PRACTICAL LESSON 6.................................................................................................................................. 41
Determining the type of foundation........................................................................................................... 41
Example 6.1. The fragment shown in fig. 6.4 shows the contour of the building and 3 boreholes. 
Construct a geotechnical section between axes 1 and 2 along axis A. The lithological 
columns for the wells are given in table 6.1. The distances between wells 10–15 
and 15–20 are 24 and 34 m, respectively................................................................................ 43
Determination of the footing depth based on the engineering-geological, hydrogeological, 
climatic and structural factors.............................................................................................. 45
Bibliographic list............................................................................................................................................... 47

Practical Lesson 1
A distinction is made between physical, strength and deformation characteristics of soil. Physical 
characteristics are divided into basic, derivative and classification characteristics. 
The basic physical characteristics of soil (table 1.1).
The basic are the characteristics determined from experience.
Table 1.1
Basic physical characteristics of soil
Name
Designation
Dimension
Calculation formula
Soil density
ρ
kg/m3
ρ = G / V
Specific gravity of soil
γ
kN/m3
γ =ρg
Soil particle density
ρs
kg/m3
ρs = Gs / Vs
Specific weight of soil particles
γs
kN/m3
γs = ρsg
Soil moisture
W
in fractions of one or %
W = Gw / Gs
Humidity on the plasticity boundary
Wp
in fractions of one or %
Wp = Gw,p / Gs
Moisture on the yield boundary
WL
in fractions of one or %
WL = Gw,L / Gs
Derived physical characteristics of the soil (table 1.2).
Table 1.2
Derived physical characteristics of soil
Name
Designation
Dimension
Calculation formula
Density of drysoil
ρd
kg/m3
ρd = ρ / (1 + W)
Specific weight of dry soil
γd
kN/m3
γd = ρdg = γ / (1 + W)
Porosity coefficient
e
in fractions of one or %
e = (ρs – ρd) / ρd = ρs / ρd – 1
Porosity
n
in fractions of one or %
n = (ρs – ρd) / ρs = 1 – ρd / ρs
Classification physical characteristics of soil (table 1.3).
Table 1.3
Derived physical characteristics of soil
Name
Designation
Dimension
Calculation formula
Number of plasticity
Ip
in fractions of one or %
Ip = WL – Wp
Fluidity index
IL
in fractions of one or %
IL = (W – Wp)/Ip
Water saturation coefficient
Sr
in fractions of one or %
Sr = (ρsW )/(ρwe)
Total moisture capacity
Wsat
in fractions of one or %
Wsat = (ρw /ρs)e 
(respond Sr = 1)
The dusty-clayey soils are characterized by the predominance of dusty and clayey particles 
in their composition and depending on the number of plasticity Ip are allocated by type according 
to table 1.4.
Table 1.4
Type of silty-clay soils
Number of plasticity, %
Sand dust
1 ≤ Ip ≤ 7 
Loam
7 < Ip ≤ 17
Clays
17 < Ip

Dusty-clay soils are  distinguished by consistency characterized by the  flowability index IL, 
according to table 1.5.
Table 1.5
Variety of dusty-clay soils
Flow index
Sandy loam
Hard
IL < 0
Plastic
0 ≤ IL ≤ 1
Fluidity
1 < IL
Loams and clays
Hard
IL < 0
Half-hard
0 ≤ IL < 0,25
Hard-plastic
0,25 ≤ IL < 0,5
Soft-plastic
0,5 ≤ IL < 0,75
Fluid-plastic
0,75 ≤ IL ≤ 1
?
1 < IL
Coarse-clastic and sandy soils are divided into types depending on their particle-size composition 
according to table 1.6.
The granulometric composition of the soil is the content by weight of groups of particles (fractions) of different size in relation to the total mass of absolutely dry soil, expressed as a percentage.
Table 1.6
Classification of sandy soils depending on particle size distribution
Variety of coarse clastic soils and sands
Particle size, mm
Particle content, % bymass
Gravel
> 2
> 50
Sand
Gravelly
> 2
> 25
Coarse
> 0,5
> 50
Medium coarse
> 0,25
> 50
Small
> 0,1
≥ 75
Dusty
> 0,1
< 75
Depending on the coefficient of porosity, there are dense, medium dense and loose sands (table 1.7).
Table 1.7
Stacking density of sandy soils
Variety of sands
Porosity coefficient e
Gravelly, coarse, 
mediumcoarse
Small
Dusty
Dense
е < 0,55
е < 0,6
е < 0,6
Medium Dense
0,6 ≤ е ≤ 0,7
0,6 ≤ е ≤ 0,75
0,6 ≤ е ≤ 0,8
Loose
е > 0,7
е > 0,75
е > 0,8
Sands and coarse clastic soils, according to the classification, can be low-moisture, wet and saturated with water (table 1.8).