Preface x

Acknowledgements xii

List of Symbols xiii

List of Property Values and Correlations in the Tables and Figures xx

1 Commonly Measured Properties 1

1.1 Moisture Content 2

1.1.1 Test Methods 2

1.2 Grading 3

1.2.1 Test Methods 4

1.3 Plasticity 7

1.3.1 Test Methods 7

1.4 Specific Gravity of Soil Particles 10

1.4.1 Test Method 10

1.5 Soil Density 11

1.5.1 Test Methods 12

1.6 Permeability 16

1.6.1 Test Methods 17

1.7 Consolidation 19

1.7.1 Test Method 20

1.8 Shear Strength 21

1.8.1 Test Methods 22

1.8.2 Choice of Shear Strength Test 27

1.9 Standard Compaction Test 27

1.9.1 Test Method 27

1.10 California Bearing Ratio 30

1.10.1 Test Method 30

1.11 Other Properties 32

1.11.1 Swelling Potential 32

1.11.2 Frost Susceptibility 32

1.11.3 Combustible Content 33

References 33

2 Grading and Plasticity 34

2.1 Grading 34

2.1.1 The influence of Grading on Soil Properties 35

2.1.2 Standard Grading Divisions 36

2.2 Plasticity 38

2.2.1 Consistency Limits 41

2.2.2 Development of the Liquid and Plastic Limit Tests 42

2.2.3 Plasticity Test Results and Plasticity Descriptions 43

2.2.4 The Shrinkage Limit Test 43

2.2.5 Consistency Limits as Indicators of Soil Behaviour 45

2.2.6 Limitations of the Use of Plasticity Limits 47

References 47

3 Density 49

3.1 Density in the Context of Soils 49

3.1.1 Density Relationships 50

3.1.2 Typical Natural Density Values 53

3.2 Compacted Density 53

3.2.1 Typical Compacted Density Values 54

3.2.2 Quick Estimates of Maximum Dry Density and Optimum Moisture Content 55

3.3 Relative Density 59

3.3.1 Field Measurement of Relative Density 59

3.3.2 SPT Correction Factors 60

3.3.3 Other Dynamic Cone Tests 64

3.3.4 Static Cone Tests 65

References 66

4 Permeability 68

4.1 Effects of Soil Macro?]Structure 69

4.2 Typical Values 69

4.3 Permeability and Grading 71

References 73

5 Consolidation and Settlement 74

5.1 Compressibility of Clays 75

5.1.1 Compressibility Parameters 75

5.1.2 Settlement Calculations Using Consolidation Theory 78

5.1.3 Settlement Calculations Using Elastic Theory 79

5.1.4 Typical Values and Correlations of Compressibility Coefficients 81

5.1.5 Settlement Corrections 84

5.2 Rate of Consolidation of Clays 86

5.3 Secondary Compression 88

5.4 Settlement of Sands and Gravels 92

5.4.1 Methods Based on Standard Penetration Tests 93

5.4.2 Methods Based on Plate Bearing Tests 101

5.5 Assessment of Settlement Parameters from Static Cone Penetration Testing 102

5.5.1 Coefficient of Volume Compressibility 102

5.5.2 Coefficient of Consolidation 103

References 105

6 Shear Strength 107

6.1 Stresses Within a Material 108

6.1.1 The Mohr Diagram 108

6.1.2 Relationships of Stresses at a Point 108

6.2 Shear Strength in Soils 113

6.3 The Choice of Total or Effective Stress Analysis 116

6.3.1 The Choice in Practice 116

6.4 Peak, Residual and Constant?]Volume Shear Strength 118

6.5 Undrained Shear Strength of Clays 119

6.5.1 Consistency and Remoulded Shear Strength 119

6.5.2 Consistency and Undisturbed Shear Strength 120

6.5.3 Estimates Using the Standard Penetration Test 126

6.5.4 Estimates Using Dynamic Cone Tests 128

6.5.5 Estimates Using Static Cone Tests 130

6.6 Drained and Effective Shear Strength of Clays 130

6.7 Shear Strength of Granular Soils 132

References 136

7 California Bearing Ratio 138

7.1 Correlations with Soil Classification Tests 139

7.2 Correlations with Soil Classification Systems 144

7.3 CBR and Undrained Shear Strength 144

7.4 An Alternative to CBR Testing 148

References 149

8 Shrinkage and Swelling Characteristics 151

8.1 Identification 151

8.2 Swelling Potential 153

8.2.1 Swelling Potential in Relation to other Properties 153

8.2.2 Reliability of Swell Predictions Based on Correlations 160

8.3 Swelling Pressure 160

References 162

9 Frost Susceptibility 164

9.1 Ice Segregation 164

9.2 Direct Measurement of Frost Susceptibility 166

9.3 Indirect Assessment of Frost Susceptibility 167

9.3.1 Grading 167

9.3.2 Plasticity 169

9.3.3 Predictions Based on Segregation Potential 171

9.4 Choosing a Suitable Method of Evaluating Frost Susceptibility 173

References 174

10 Susceptibility to Combustion 175

Reference 176

11 Soil-Structure Interfaces 177

11.1 Lateral Pressures in a Soil Mass 177

11.1.1 Earth Pressure at Rest 178

11.2 Friction and Adhesion at Interfaces 180

11.2.1 Values Relating to Specific Types of Structure 180

References 184

Appendix A Soil Classification Systems 186

A.1 Systems Based on the Casagrande System 187

A.1.1 The Unified System 187

A.1.2 The ASTM System 189

A.1.3 The British Standard System 189

A.2 The AASHTO System 194

A.3 Comparison of the Unified, AASHTO and BS Systems 198

References 199

Appendix B Sampling Methods 200

B.1 Pits and Borings 201

B.1.1 Trial Pits 201

B.1.2 Light Cable Percussion Borings 202

B.1.3 Rotary Boring 204

B.1.4 Window Samplers and Windowless Samplers 204

B.2 Sampling and Samplers 206

B.2.1 Disturbed Samples 206

B.2.2 Open?]Drive Samplers 206

B.2.3 Piston Samplers 209

B.2.4 The Standard Penetration Test 210

B.3 Probes 212

B.3.1 Dynamic Probes 212

B.3.2 Static Probes 213

Reference 217

Index 218