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Ian Smith. Smith's Elements of Soil Mechanics
Table of Contents
List of Tables
List of Illustrations
Guide
Pages
Smith's Elements of Soil Mechanics
Preface
About the Author
Notation Index
About the Companion Website
Chapter 1 Classification and Physical Properties of Soils. Learning objectives:
1.1 Agricultural and engineering soil
Topsoil
Subsoil
Hardpan
Soil
Bedrock
Groundwater
1.2 The rock cycle
1.2.1 Rock
Igneous rocks
Sedimentary rocks
Metamorphic rocks
Identification of rocks
1.2.2 Soil
Transported soil (gravels, sands, silts and clays)
Residual soil (topsoil, laterites)
Organic soil
1.2.3 Granular and cohesive soils
1.3 Clay soils
1.3.1 Classes of clay minerals
Kaolinite group
Illite group
Montmorillonite group
1.3.2 Structure of a clay deposit. Macrostructure
Microstructure
1.4 Field identification of soil
Common types of soil
1.5 Soil classification laboratory testing. 1.5.1 Drying soils
1.5.2 Determination of water content, w
Example 1.1 Water content determination
1.5.3 Granular soils – particle size distribution
The effective size of a distribution, D10
Grading of a distribution
The uniformity coefficient Cu and the coefficient of curvature, Cc
Example 1.2 Particle size distribution
1.5.4 Sedimentation analysis
Example 1.3 Pipette analysis
1.5.5 Cohesive soils – liquid and plastic limit tests
Liquid limit (wL) and plastic limit (wP)
Plasticity index (IP)
Liquidity index
Shrinkage limit (wS)
Determination of liquid and plastic limits
Liquid limit test
Plastic limit test
Example 1.4 Consistency limits tests
1.5.6 Activity of a clay
1.6 Soil classification and description. 1.6.1 Soil classification
Example 1.5 Soil classification (i)
Example 1.6 Soil classification (ii)
1.6.2 Description of soils
1.7 Soil properties
1.7.1 Void ratio and porosity
1.7.2 Degree of saturation, Sr
1.7.3 Particle density, ρs and specific gravity, Gs
Example 1.7 Particle density
1.7.4 Density and unit weight
Density of soil. Bulk density
Dry density
Unit weight, or weight density, of soil
Bulk unit weight, γ
Saturated unit weight, γsat
Dry unit weight, γd
Effective, or buoyant, unit weight, γ'
Additional expressions for densities
Relationship between density and unit weight values
Example 1.8 Dry unit weight
Relationship between w, γd and γ
Relationship between e, w and Gsfor a saturated soil
Relationship between e, w and Gs for a partially saturated soil
Example 1.9 Physical properties determination
1.7.5 Density index, ID
1.7.6 Summary of soil physical relations
Exercises. Exercise 1.1
Exercise 1.2
Exercise 1.3
Exercise 1.4
Exercise 1.5
Exercise 1.6
Exercise 1.7
Exercise 1.8
Chapter 2 Permeability and Flow of Water in Soils. Learning objectives:
2.1 Subsurface water
2.1.1 Saturation zone
2.1.2 Aeration zone
Capillary fringe
Intermediate belt
Soil belt
2.2 Flow of water through soils
2.2.1 Saturated flow
2.2.2 Hydraulic head
1.2.1 Excess head
2.2.3 Seepage velocity
2.2.4 Hydraulic gradient
2.3 Darcy's law of saturated flow
2.4 Coefficient of permeability, k
2.5 Determination of permeability in the laboratory
2.5.1 Constant head test
Example 2.1 Constant head test
2.5.2 The falling head permeameter
Example 2.2 Falling head permeameter
2.5.3 The hydraulic consolidation cell (Rowe cell)
2.6 Determination of permeability in the field. 2.6.1 Field pumping test
Example 2.3 Pumping test
2.6.2 Borehole tests
Open system
Closed system
Packer test
2.7 Approximation of coefficient of permeability
Typical ranges of coefficient of permeability
Example 2.4 Approximation of k
2.8 General differential equation of flow
2.9 Potential and stream functions
2.10 Flow nets
Flow lines
Equipotential lines
2.10.1 Flow quantities
2.10.2 Calculation of seepage quantities
2.10.3 Drawing a flow net
Example 2.5 Flow net seepage
2.11 Critical flow conditions. 2.11.1 Critical hydraulic gradient, ic
2.11.2 Seepage force
2.11.3 Alleviation of piping
Example 2.6 Buoyant uplift
Units of pressure
2.12 Design of soil filters
Example 2.7 Filter material limits
2.13 Capillarity and unsaturated soils
2.13.1 Surface tension
2.13.2 Capillary effects in soil
2.13.3 Soil suction
2.13.4 The water retention curve
2.13.5 Measurement of soil suction
The psychrometer method
The filter paper method
The tensiometer
2.14 Earth dams. 2.14.1 Seepage patterns through an earth dam
2.14.2 Types of flow occurring in an earth dam
2.14.3 Parabolic solutions for seepage through an earth dam
2.15 Seepage through non‐uniform soil deposits. 2.15.1 Stratification in compacted soils
2.15.2 Calculation of seepage quantities in an anisotropic soil
Example 2.8 Seepage loss through dam (i)
Example 2.9 Seepage loss through dam (ii)
Example 2.10 Seepage loss through dam (iii)
2.15.3 Permeability of sedimentary deposits
Example 2.11 Quantity of flow
2.15.4 Seepage through soils of different permeabilities
2.15.5 Refraction of flow lines at interfaces
Exercises. Exercise 2.1
Exercise 2.2
Exercise 2.3
Exercise 2.4
Exercise 2.5
Exercise 2.6
Exercise 2.7
Chapter 3 Stresses in the Ground. Learning objectives:
3.1 State of stress in a soil mass. 3.1.1 Stress–strain relationships
3.1.2 Stresses within a soil mass
3.1.3 Normal stress and strain
3.1.4 Shear stress and strain
3.1.5 Volumetric strain and bulk modulus
3.1.6 Plane strain conditions
3.1.7 One‐dimensional compression
3.2 Total stress
3.3 Pore water pressure
3.4 Effective stress
Example 3.1 Total and effective stress
Example 3.2 Distributions of total stress, pwp, and effective stress
3.5 Undrained and drained conditions in a soil
3.6 Stresses induced by applied loads. 3.6.1 Stresses induced by uniform surface surcharge
Example 3.3 Effective stress with surface loading
Example 3.4 Applied wide loading
Example 3.5 Changes in effective stress through time
3.6.2 Stresses induced by point load
Example 3.6 Vertical stress increments beneath a point load
3.6.3 Stresses induced by uniform rectangular load
Example 3.7 Vertical stress increments beneath a foundation
Example 3.8 Vertical stress increments beneath circular foundation
3.6.4 Irregularly shaped foundations
3.6.5 Bulbs of pressure
3.6.6 Shear stresses
Shear stresses under a rectangular foundation
Example 3.9 Shear stress induced by foundation loading
3.6.7 Contact pressure
Exercises. Exercise 3.1
Exercise 3.2
Exercise 3.3
Exercise 3.4
Chapter 4 Shear Strength of Soils. Learning objectives:
4.1 Shear strength of soil. 4.1.1 Frictional resistance to movement
4.1.2 Complex stress
Principal plane
Principal stress
4.1.3 The Mohr circle diagram
Example 4.1 Mohr’s circle
Limit conditions
Example 4.2 Angle of shearing resistance and angle of failure plane
Strength envelopes
Relationship between ϕ and θ
4.1.4 Cohesion
4.1.5 Coulomb's law of soil shear strength
Effective stress, σ′
4.1.6 Modified Coulomb’s law
4.1.7 The Mohr–Coulomb yield theory
4.2 Determination of the shear strength parameters
4.2.1 The shear box test
Example 4.3 Shear box test (i)
Example 4.4 Shear box test (ii)
4.2.2 The effect of density on shear strength
4.2.3 Triaxial testing
Determination of the additional axial stress
Principal stresses
Types of failure
The triaxial tests
4.2.4 The unconsolidated undrained (UU) test
Example 4.5 Quick undrained triaxial test
4.2.5 The consolidated drained (CD) test
Test set up and saturation
Consolidation stage
Shearing stage
Example 4.6 Consolidated drained triaxial test
4.2.6 The consolidated undrained (CU) test
Example 4.7 Consolidated undrained triaxial test (i)
4.2.7 Testing with back pressures
Example 4.8 Consolidated undrained triaxial test (ii)
4.2.8 Comparison of strength parameters obtained from different triaxial tests
4.2.9 Triaxial extension test
4.2.10 The unconfined compression test
4.3 The pore pressure coefficients A and B
Effect of Δσ3
Effect of Δσ1 – Δσ3
Values of A
Variation of A
Example 4.9 Pore pressure coefficient A
Example 4.10 Pore pressure coefficients
4.4 Behaviour of soil during shearing
4.4.1 Undrained shear
4.4.2 Drained and consolidated undrained shear
4.5 Operative strengths of soils
4.5.1 Operative strengths of sands and gravels
4.5.2 Operative strengths of silts
4.5.3 Operative strengths of clays
Soft or normally consolidated clay
Overconsolidated clay
4.6 Sensitivity of clays
Thixotropy
Liquidity index IL
4.7 Residual strength of soil
4.7.1 Residual strength of clays
4.7.2 Residual strength of silts and silty clays
4.7.3 Residual strength of sands
Exercises. Exercise 4.1
Exercise 4.2
Exercise 4.3
Exercise 4.4
Exercise 4.5
Exercise 4.6
Exercise 4.7
Chapter 5 Stress Paths and the Critical State. Learning objectives:
5.1 Stress paths in two‐dimensional space
The K f line
Example 5.1: Kf line
The K 0 line
Example 5.2: Effective stress paths: normally consolidated clay
Example 5.3: Effective stress paths: overconsolidated clay
5.2 Stress paths in three‐dimensional space
5.3 Isotropic consolidation
5.3.1 Isotropically consolidated clay
5.3.2 Equivalent isotropic consolidation pressure, p′e
5.3.3 Comparison between isotropic and one‐dimensional consolidation
5.4 Stress paths in the triaxial apparatus
5.4.1 Drained compression test
5.4.2 Undrained compression test
5.5 Introduction to critical state soil mechanics
5.5.1 The critical state line
5.5.2 The equation of the critical state line
5.6 Undrained and drained planes. 5.6.1 Undrained planes
Example 5.4: Failure conditions in an undrained test
5.6.2 Drained planes
Example 5.5: Failure conditions in a drained test
Example 5.6: Drained and undrained failure conditions
5.7 State boundaries. 5.7.1 The Roscoe surface
Example 5.7: Roscoe surface
5.7.2 Overconsolidated clays – Hvorslev surface
5.7.3 The overall state boundary
5.7.4 Equation of the Hvorslev surface
5.8 Residual and critical strength states
Exercises. Exercises 5.1
Exercise 5.2
Exercise 5.3
Exercise 5.4
Exercise 5.5
Exercise 5.6
Chapter 6 Eurocode 7. Learning objectives:
6.1 Preface to Chapter 6
6.2 Introduction to the Eurocodes. 6.2.1 The Eurocode Programme
6.2.2 Scope of the Eurocodes
6.2.3 Eurocode Parts and National Annexes
6.2.4 Design philosophy
Section A: Eurocode 7 – first generation (EN 1997:2004 and 2007) 6.3 Eurocode 7 – first generation
6.3.1 Contents of Eurocode 7
6.3.2 Using Eurocode 7: basis of geotechnical design
6.4 Geotechnical design by calculation
6.4.1 Characteristic values of geotechnical parameters
6.4.2 Partial factors of safety and design values
6.4.3 Design values of actions
Example 6.1: Design value of action
6.4.4 Design values of geotechnical parameters
Example 6.2: Design value of geotechnical parameters
6.4.5 Design values of geometrical data
6.4.6 Design effects of actions
6.4.7 Design resistances
6.5 Ultimate limit states
6.6 The EQU limit state
Example 6.3: EQU limit state
6.7 The GEO limit state and design approaches
6.7.1 Design approaches
Example 6.4: Design approaches; design actions
Example 6.5: Design approaches; design geotechnical parameters
6.7.2 The over‐design factor and the degree of utilisation
Example 6.6: GEO limit state: forward sliding
6.8 Serviceability limit states
6.9 Geotechnical design report
Section B: Eurocode 7 – second generation (EN 1997: 202x) 6.10 Eurocode 7 – second generation
6.11 Basis of structural and geotechnical design – EN 1990:202x. 6.11.1 Introduction
6.11.2 Design actions and the design effects of actions
6.11.3 Design material properties and design resistance
6.11.4 Consequence classes
6.11.5 Design cases
6.12 Design of a geotechnical structure – EN 1997: Parts 1, 2 and 3 (202x)
6.12.1 Reliability management
6.12.2 Development of the ground model
6.12.3 Development of the geotechnical design model
6.12.4 Design verification
6.12.5 Water actions
6.13 Verification by the partial factor method
Ultimate limit states
Serviceability limit states
6.13.1 Determining design values of actions and effect of actions
Example 6.7: Design actions and effects of actions
6.13.2 Determining design values of material properties and resistances
Example 6.8: Design material properties and resistances
6.14 Execution, Monitoring and Reporting. 6.14.1 Execution and monitoring
6.14.2 Reporting
Ground investigation report (GIR)
Geotechnical design report (GDR)
Geotechnical construction record (GCR)
Geotechnical test report
Chapter 7 Site Investigation. Learning objectives:
7.1 Eurocode 7 and execution standards
7.2 Planning of ground investigations
7.2.1 Desk study
Sources of information
Geological maps
Topographical maps
Soil survey maps
Aerial photographs and imagery
Existing site investigation reports
7.2.2 Site reconnaissance
7.2.3 Planning field investigations and laboratory tests
Spacing of ground investigation points
Minimum depth of ground investigation points
First generation
Second generation
7.3 Site exploration methods. 7.3.1 Trial pits
7.3.2 Hand excavated boreholes
7.3.3 Boreholes
Cable percussion boring
Rotary drilling
Sonic drilling
7.4 Soil and rock sampling
7.4.1 Soil sampling
Disturbed samples
Undisturbed samples (cohesive soil)
Undisturbed samples (sands)
7.4.2 Degree of sample disturbance
Example 7.1: Area ratio
7.4.3 Categories of sampling methods and quality classes of samples
7.4.4 Rock sampling
7.5 Groundwater measurements
7.5.1 Open systems
7.5.2 Closed systems
Hydraulic system
Pneumatic system
Electrical system
7.6 Field tests in soil and rock
7.6.1 Cone penetration test (CPT)
7.6.2 Standard penetration test (SPT)
Correction factors to the measured N‐value
Example 7.2: Standard Penetration Test
Correlations between blow count and density index
7.6.3 Dynamic probing test
Example 7.3: Dynamic probing test
7.6.4 Pressuremeter test
7.6.5 Plate loading test (PLT)
7.6.6 Field vane test
Example 7.4: Field vane test
7.6.7 Testing of geotechnical structures
7.7 Geotechnical reports
Preamble
Description of site
Description of subsoil conditions encountered
Borehole logs
Laboratory and in situ tests results
Evaluation of geotechnical information
Ground model
Exercises. Exercise 7.1
Exercise 7.2
Exercise 7.3
Exercise 7.4
Exercise 7.5
Chapter 8 Lateral Earth Pressure. Learning objectives:
8.1 Earth pressure at rest
8.2 Active and passive earth pressure
8.3 Rankine's theory: granular soils, active earth pressure. 8.3.1 Horizontal soil surface
8.3.2 Sloping soil surface
Example 8.1: Rankine active thrust
8.3.3 Point of application of the total active thrust
Example 8.2: Rankine active thrust; more than one soil
Example 8.3: Rankine active pressure; presence of groundwater
8.4 Rankine's theory: granular soils, passive earth pressure. 8.4.1 Horizontal soil surface
8.4.2 Sloping soil surface
8.4.3 Rankine's assumption on wall friction
8.5 Rankine's theory: cohesive soils
8.5.1 Effect of cohesion on active pressure
8.5.2 Depth of the tension zone
Example 8.4: Lateral pressure distribution
8.5.3 The occurrence of tensile cracks
8.5.4 Effect of cohesion on passive pressure
8.6 Coulomb's wedge theory: active earth pressure
8.6.1 Granular soils
Example 8.5: Coulomb active thrust
Example 8.6: Coulomb active thrust; more than one soil
8.6.2 The effect of cohesion
Example 8.7: Coulomb Ka and Kac
8.6.3 Point of application of total active thrust
8.7 Coulomb's wedge theory: passive earth pressure. 8.7.1 Granular soils
8.7.2 The effect of cohesion
8.8 Surcharges
8.8.1 Uniform surcharge. Soil surface horizontal
Soil surface sloping at angle β to horizontal
Example 8.8: Uniform surcharge (i)
Example 8.9: Uniform surcharge (ii)
8.8.2 Line load
8.8.3 Compaction effects
8.9 Choice of method for determination of active pressure
8.10 Backfill material
8.10.1 Drainage systems
8.10.2 Differential hydrostatic head
Example 8.10: Thrust due to saturated soil
8.11 Influence of wall yield on design
8.12 Design parameters for different soil types. 8.12.1 Active earth conditions
Sands and gravels
Clays
Soft or normally consolidated clay
Overconsolidated clay
Silts
Rainwater in tension cracks
8.12.2 Passive earth conditions. Granular soils
Normally consolidated clays
Overconsolidated clays
Silts
Exercises. Exercise 8.1
Exercise 8.2
Exercise 8.3
Exercise 8.4
Chapter 9 Retaining Structures. Learning objectives:
9.1 Main types of retaining structures
9.2 Gravity walls. 9.2.1 Mass construction gravity walls
9.2.2 Reinforced concrete walls. Cantilever wall
Counterfort wall
Relieving platforms
9.2.3 Crib walls
9.2.4 Gabion walls
9.3 Embedded walls
9.3.1 Sheet pile walls
Cantilever wall
Anchored wall
9.3.2 Diaphragm walls
9.3.3 Contiguous and secant bored pile walls. Contiguous bored pile walls
Secant bored pile walls
9.4 Design of retaining structures. 9.4.1 Failure modes of retaining structures
9.4.2 Limit states
9.4.3 Design to Eurocode 7 (first generation)
9.4.4 Design to Eurocode 7 (second generation)
9.5 Design of gravity retaining walls
9.5.1 Toppling
9.5.2 Base resistance to sliding. Granular soils and drained clays
Undrained clays
Shear key
9.5.3 Bearing pressures on soil
9.5.4 Earth pressure coefficients
Example 9.1 Mass concrete wall; toppling and sliding by Eurocode 7 (first generation)
Example 9.2 Mass concrete wall; toppling and sliding by Eurocode 7 (second generation)
Example 9.3 Strength and stability checks by traditional and Eurocode 7 (first generation) approaches
Example 9.4 Strength and stability checks by Eurocode 7 (second generation)
9.6 Design of sheet pile walls
9.6.1 Cantilever walls
Limit state design method to establish required design depth
Traditional methods
9.6.2 Dealing with passive earth pressure. Eurocode 7 – first generation
Eurocode 7 – second generation
Example 9.5 Cantilever sheet pile wall
9.6.3 Anchored and propped walls
9.6.4 Depth of embedment for anchored walls
Example 9.6 Anchored sheet pile wall
9.6.5 Reduction of design moments in anchored sheet pile walls
9.6.6 Treatment of groundwater conditions
Example 9.7 Water pressure distribution
Eurocode 7 – first generation
Eurocode 7 – second generation
9.7 Braced excavations
9.8 Reinforced soil
Soil fill
Reinforcing elements
Facing units
Design of reinforced soil retaining structures
9.9 Soil nailing
Exercises. Exercise 9.1
Exercise 9.2
Exercise 9.3
Exercise 9.4
Exercise 9.5
Chapter 10 Bearing Capacity and Shallow Foundations Design. Learning objectives:
10.1 Bearing capacity terms
Ultimate bearing capacity
Safe bearing capacity
Allowable bearing pressure
10.2 Types of foundation. Strip foundation
Pad footing
Raft foundation
Pile foundation
Pier foundation
Shallow foundation
Deep foundation
10.3 Ultimate bearing capacity of a foundation
10.3.1 Earth pressure theory
10.3.2 Slip circle methods
Cohesion of end sectors
10.3.3 Plastic failure theory. Forms of bearing capacity failure
Prandtl's analysis
Terzaghi's analysis
10.3.4 Summary of bearing capacity formula
10.3.5 Choice of soil parameters
Example 10.1 Ultimate bearing capacity (Terzaghi) in short term and long term
Example 10.2 Ultimate bearing capacity (Terzaghi); effect of ϕ′
10.4 Determination of the safe bearing capacity
10.5 The effect of groundwater on bearing capacity. 10.5.1 Water table below the foundation level
10.5.2 Water table above the foundation level
10.6 Developments in bearing capacity equations
10.6.1 General form of the bearing capacity equation
10.6.2 Shape factors
10.6.3 Depth factors
Example 10.3 Ultimate bearing capacity (Meyerhof) in short term and long term
Example 10.4 Safe bearing capacity
10.6.4 Effect of eccentric and inclined loading on foundations
Eccentric loads
Inclined loads
10.7 Designing spread foundations to Eurocode 7 (first generation)
10.7.1 Design by calculation
Example 10.5 Traditional, and Eurocode 7 (first generation), approaches (i)
Example 10.6 Traditional, and Eurocode 7 (first generation), approaches (ii)
Example 10.7 Bearing resistance – undrained and drained (Eurocode 7 first generation)
Solution:
Example 10.8 Bearing resistance – vertical and horizontal loading (Eurocode 7 first generation)
10.7.2 Design by prescriptive method
10.8 Designing spread foundations to Eurocode 7 (second generation)
Example 10.9 Eurocode 7 (second generation) (i)
Example 10.10 Eurocode 7 (second generation) (ii)
Solution:
10.9 Non‐homogeneous soil conditions
10.10 Estimates of bearing capacity from in situ testing. 10.10.1 The plate loading test
Example 10.11 Estimation of ultimate bearing capacity from plate load test
10.10.2 Standard penetration test
Example 10.12 Estimate of acceptable bearing capacity from SPT
Exercises. Exercise 10.1
Exercise 10.2
Exercise 10.3
Exercise 10.4
Chapter 11 Pile Foundations. Learning objectives:
11.1 Introduction
11.2 Classification of piles
11.2.1 End bearing
11.2.2 Friction
11.2.3 Combination
11.3 Method of installation
11.3.1 Driven piles
Precast concrete
Timber
Steel piles: Tubular, box, or H‐section
Jetted pile
Jacked pile
Screw pile
11.3.2 Bored and cast‐in‐place piles
11.3.3 Driven and cast‐in‐place piles
11.3.4 Large diameter bored piles
11.4 Pile load testing
11.4.1 Static load tests. Maintained load test (MLT)
Constant rate of penetration test (CRP)
Design failure load
11.4.2 Dynamic load tests
11.4.3 Soil tests
11.5 Determination of the bearing resistance of a pile
11.5.1 Cohesive soils
The adhesion factor α
11.5.2 Granular soils
Example 11.1 Undrained analysis
Solution:
Example 11.2 Drained analysis
Solution:
11.5.3 Determination of soil piling parameters from in situ tests
Example 11.3 Allowable load from in situ testing results
Solution:
11.5.4 Negative skin friction, or downdrag
11.6 Pile groups. 11.6.1 Action of pile groups
Efficiency of a pile group
11.6.2 End‐bearing piles
11.6.3 Friction/combination piles. Pile groups in granular soils
Pile groups in cohesive soils
11.6.4 Settlement effects in pile groups
11.7 Designing pile foundations to Eurocode 7 (first generation)
11.7.1 Note on the UK National Annex, NA EN 1997‐1:2004
11.7.2 Ultimate compressive resistance from static load tests
Example 11.4 Static load tests (to UK National Annex)
Example 11.5 Maintained load tests (to EN 1997‐1:2004)
11.7.3 Ultimate compressive resistance from ground tests results
Example 11.6 Design from ground tests results
11.7.4 Ultimate compressive resistance from dynamic tests results
11.8 Designing pile foundations to Eurocode 7 (second generation) 11.8.1 Geotechnical reliability
11.8.2 Design, by calculation, of single axially loaded piles
Calculation Method A
Calculation Method B
11.8.3 Verification of ultimate axial resistance of pile groups
Example 11.7 Static load tests (to Eurocode 7 second generation)
Example 11.8 Single, and group, pile verification (to Eurocode 7 second generation)
Example 11.9 Design from ground tests results (to Eurocode 7 second generation)
11.9 Piles subjected to additional, non‐compressive loadings
11.9.1 Piles in tension
11.9.2 Transversely loaded piles
Exercises. Exercise 11.1
Exercise 11.2
Exercise 11.3
Exercise 11.4
Exercise 11.5
Chapter 12 Foundation Settlement and Soil Compression. Learning objectives:
12.1 Settlement of a foundation
Elastic compression
Primary compression
Secondary compression
12.2 Immediate settlement
12.2.1 Cohesive soils
Immediate settlement of a thin clay layer
Example 12.1 Immediate settlement of a rigid foundation
Example 12.2 Immediate settlement of a flexible foundation
The effect of depth
Determination of modulus of elasticity
12.2.2 Granular soils
Meyerhof's method
De Beer and Martens' method
Schmertmann's method
Example 12.3 Settlement on a cohesionless soil
The plate loading test
12.3 Consolidation settlement
12.3.1 One‐dimensional consolidation
12.3.2 The consolidation test
12.3.3 Volumetric change
12.3.4 The Rowe cell
12.3.5 Coefficient of volume compressibility, mv
Example 12.4 Consolidation test
12.3.6 The virgin consolidation curve
Compression curve for a normally consolidated clay
Compression curve for an overconsolidated clay
Evaluation of consolidation settlement from the compression index
Determination of compression index CC
Example 12.5 Approximate settlement of a soft clay
12.4 Application of consolidation test results
12.5 General consolidation
12.6 Settlement analysis
Example 12.6 Total settlement
Example 12.7 Total settlement using SPT results
12.7 Eurocode 7 serviceability limit state. 12.7.1 First generation: EN 1997‐1:2004
12.7.2 Second generation: EN 1997‐1:202x and EN 1997‐3:202x
Example 12.8 Serviceability limit state
12.8 Stress paths in the oedometer
12.9 Stress path for general consolidation
Example 12.9 Effective stress paths
Exercises. Exercise 12.1
Exercise 12.2
Exercise 12.3
Exercise 12.4
Exercise 12.5
Exercise 12.6
Exercise 12.7
Exercise 12.8
Chapter 13 Rate of Foundation Settlement. Learning objectives:
13.1 Analogy of consolidation settlement
13.2 Distribution of the initial excess pore pressure, ui
13.3 Terzaghi's theory of consolidation
13.4 Average degree of consolidation
13.5 Drainage path length
13.6 Determination of the coefficient of consolidation, cv, from the consolidation test
The square root of time fitting method
13.7 Determination of the permeability coefficient from the consolidation test
13.8 Determination of the consolidation coefficient from the triaxial test
Example 13.1: Consolidation test
Solution:
13.9 The model law of consolidation
Example 13.2: Consolidation in the field
Solution:
Example 13.3: Degree of consolidation
Solution:
13.10 Consolidation during construction
Example 13.4: Settlement versus time relationship
Solution:
13.11 Consolidation by drainage in two and three dimensions
13.12 Numerical determination of consolidation rates
Maclaurin’s series
Taylor’s series
Explicit finite difference equation
Impermeable boundary conditions
Errors associated with the explicit equation
Example 13.5: Degree of consolidation by finite difference method
Solution:
Degree of consolidation
13.13 Construction pore pressures in an earth dam
Example 13.6: Excess pore pressure distribution by numerical method
Solution:
13.14 Numerical solutions for two‐ and three‐ dimensional consolidation. 13.14.1 Two‐dimensional consolidation
Impermeable boundary condition
13.14.2 Three‐dimensional consolidation
Value of r
13.14.3 Determination of initial excess pore water pressure values
13.15 Wick, or prefabricated vertical, drains
13.15.1 Design of a prefabricated vertical drain system. Key aspects
Consolidation theory
Equivalent radius, R
Determination of consolidation rates from curves
Design procedure
Smear effects
Effectiveness of prefabricated vertical drains
Example 13.7: Prefabricated vertical drain system
Solution:
13.16 Preconsolidation by surface loading
Exercises. Exercise 13.1
Exercise 13.2
Exercise 13.3
Exercise 13.4
Exercise 13.5
Exercise 13.6
Chapter 14 Stability of Slopes. Learning objectives:
Methods of analysis
14.1 Planar failures
14.1.1 Seepage forces in a granular slope subjected to rapid drawdown
14.1.2 Flow parallel to the surface and at the surface
Example 14.1: Safe angle of slope
Solution:
14.1.3 Planar translational slip
14.2 Rotational failures
14.2.1 Total stress analysis
14.2.2 Effect of tension cracks
Example 14.2: Factor of safety against sliding
Solution:
14.2.3 The Swedish, or Fellenius, method of slices analysis
Total stress analysis
Effective stress analysis
Example 14.3: Swedish method of slices: undrained state
Solution:
Example 14.4: Swedish method of slices: drained state
Solution:
Example 14.5: Swedish method of slices, two soils
Solution:
14.2.4 Pore pressure ratio, ru
Rapid construction of an embankment
Steady seepage
Rapid drawdown
14.2.5 Effective stress analysis by Bishop's method
Example 14.6: Bishop's conventional method
Solution:
Bishop's routine, or rigorous, method
Example 14.7: Bishop's conventional and rigorous methods
Solution:
Example 14.8: Bishop's rigorous method
Solution:
14.3 Slope stability design charts
14.3.1 Rapid determination of F for a homogeneous, regular slope
Example 14.9: Taylor's charts (i)
Solution:
Example 14.10: Taylor's charts (ii)
Solution:
14.3.2 Homogeneous slope with a constant pore pressure ratio
14.4 Wedge failure
Example 14.11: Wedge failure
Solution:
14.5 Slope stability assessment to Eurocode 7. 14.5.1 First generation: EN 1997‐1:2004
14.5.2 Second generation: EN 1997‐1:202x and EN 1997‐3:202x
Example 14.12: Taylor's charts to Eurocode 7 (first generation)
Solution:
Example 14.13: Taylor's charts to Eurocode 7 (second generation)
Solution:
Example 14.14: Rotational failure to Eurocode 7 (first generation)
Solution:
Example 14.15: Rotational failure to Eurocode 7 (second generation)
Solution:
Example 14.16: Planar failure to Eurocode 7 (first generation)
Solution:
Example 14.17: Planar failure to Eurocode 7 (second generation)
Solution:
Exercises. Exercise 14.1
Exercise 14.2
Exercise 14.3
Exercise 14.4
Exercise 14.5
Exercise 14.6
Exercise 14.7
Exercise 14.8
Exercise 14.9
Chapter 15 Soil Compaction, Highway Foundation Design and Ground Improvement. Learning objectives:
15.1 Field compaction of soils
Smooth wheeled roller
Vibratory roller
Pneumatic‐tyred roller
Sheepsfoot roller
Deep impact rollers
The grid roller
Rammers and vibrators
15.2 Laboratory compaction of soils. 15.2.1 British standard compaction tests
The 2.5 kg rammer method
The 4.5 kg rammer method
The vibrating hammer method
15.2.2 Soils susceptible to crushing during compaction
Preparation of the soil at different water contents
15.2.3 Determination of the dry density–moisture content relationship
15.2.4 Percentage air voids, Va. Saturation line
Air voids line
15.2.5 Correction for gravel content
Example 15.1: 2.5 kg compaction test
Solution:
Example 15.2: Corrected ρdmax and omc for gravel content
Solution:
15.3 Specification of the field compacted density
Overcompaction
15.3.1 Compactive effort in the field
15.3.2 Relative compaction
15.3.3 Method compaction
15.3.4 End‐product compaction
15.3.5 Air voids percentage
15.4 Field measurement tests
15.4.1 Bulk density determination
Core‐cutter method
Sand replacement test
Example 15.3: Sand replacement test
Solution:
Nuclear density gauge
Non‐nuclear density gauge
15.4.2 Water content determination
Nuclear and non‐nuclear density gauges
Time domain reflectometry (TDR)
Soil moisture capacitance probe
15.5 Highway design
15.5.1 Components of a flexible road
15.5.2 Highway design in the UK
Subgrade stiffness
Capping layer
Restricted and performance design methods
15.5.3 The California bearing ratio test
Laboratory CBR test
Surcharge effect
In situ CBR test
Estimation of CBR values
Example 15.4: CBR test
Solution:
15.5.4 Drainage and weather protection
15.5.5 Frost susceptibility of subgrades and base materials
15.5.6 Traffic assessment
15.5.7 Design life of a road
15.6 Subgrade improvement through soil stabilisation
15.7 The moisture condition value, MCV
15.7.1 Determination of MCV
Example 15.5: MCV test
Solution:
15.7.2 The calibration line of a soil
15.7.3 The use of calibration lines in site investigation
15.8 Ground improvement techniques
15.8.1 Consolidation by preloading
15.8.2 Deep compaction techniques
Vibro‐compaction
Vibro‐flotation
Vibro‐replacement (stone columns)
Dynamic consolidation
15.8.3 Grouting
15.8.4 Prefabricated vertical drains
15.8.5 Geosynthetics
Separation
Reinforcement
Filtration
Drainage
Liquid barrier
15.9 Environmental geotechnics
Exercises. Exercise 15.1
Exercise 15.2
Exercise 15.3
Exercise 15.4
Chapter 16 An Introduction to Constitutive Modelling in Geomechanics. Learning objectives:
16.1 Introduction
16.2 Stress‐strain behaviour
16.3 Selecting the most appropriate constitutive model
16.4 Linear elasticity theory
16.4.1 Linear isotropic elasticity
16.4.2 Stress, strain and stiffness tensors
16.4.3 Limitations of linear elastic constitutive models
16.5 Rigid plasticity theory. 16.5.1 Rigid plastic model
16.5.2 Limitations of the rigid plasticity theory
16.6 Elastoplasticity theory
16.6.1 The yield criterion
(a) Consistency condition
(b) Examples of yield criteria (i) Tresca criterion
(ii) Von‐Mises criterion
(iii) Drucker–Prager criterion
(iv) Mohr–Coulomb criterion
16.6.2 The plastic flow rule
16.6.3 The hardening rule
References
Index
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