Essentials of Soil Mechanics

Symbols ix

Acknowledgments xiii

About the Companion Website xv

Introduction xvii

1 Soil Composition 1

1.1 Phase Diagrams 1

1.2 Application of Phase Diagrams: Compaction 3

1.3 Coarse- and Fine-Grained Soils 6

1.3.1 Coarse-Grained Soils 6

1.3.2 Fine-Grained Soils 8

1.4 Unified Soil Classification System 11

1.5 Chapter Recap 12

Problems 12

Solutions 13

2 Stresses in the Ground 15

2.1 Vertical Total Stress 15

2.2 Pore Water Pressure 17

2.3 Vertical Effective Stress 18

2.4 Horizontal Effective Stress 19

2.5 Horizontal Total Stress 19

2.6 Mohr Circles 20

2.6.1 Flat Ground Example 23

2.6.2 Sloping Ground Example 26

2.7 Stresses in the Ground due to Surface Loads 28

2.8 Chapter Recap 31

Problems 32

Solutions 33

3 Seepage 37

3.1 What Causes Seepage 38

3.2 Seepage-Related Pore Water Pressures 41

3.3 Hydraulic Gradient at Points of Interest 42

3.4 Flow Rate 43

3.5 Chapter Recap 47

Problems 47

Solutions 48

4 Consolidation 51

4.1 What Happens During Consolidation 51

4.2 Magnitude of Consolidation 53

4.2.1 Case A: Normally Consolidated Clay 54

4.2.2 Case B: Overconsolidated Clay 58

4.3 Changes in Stress State During Consolidation Loading and Unloading 60

4.4 Time-Rate of Consolidation 62

4.5 Chapter Recap 67

Problems 67

Solutions 68

5 Shear Strength 69

5.1 The Mohrâ"Coulomb Failure Line 69

5.2 Drained and Undrained Loading Conditions 71

5.3 Example Stability Problem with a Sand Foundation 75

5.4 Example Stability Problem with a Clay Foundation 78

5.5 Undrained Shear Strength for Partially Saturated Soils 84

5.6 Shear Strength for Changes in Groundwater Level 85

5.7 Chapter Recap 86

Problems 87

Solutions 88

6 Active and Passive Pressures 91

6.1 Active Pressures 91

6.2 Passive Pressures 94

6.3 Summary of Rankineâs Theory 97

6.4 Movements Required for Active and Passive Pressures 97

6.5 Chapter Recap 99

Problems 100

Solutions 100

7 Site Investigations 103

7.1 A General Approach to Site Investigations 103

7.1.1 Understand What Is Planned for the Site 103

7.1.2 Look for Existing Information About the Site 104

7.1.3 Visit the Site 104

7.1.4 Develop a Model and Identify Data Gaps 104

7.1.5 Develop a Subsurface Exploration Program 105

7.2 An Example Site Investigation 107

7.2.1 Understand What Is Planned for the Site 107

7.2.2 Look for Existing Information About the Site 108

7.2.3 Visit the Site 108

7.2.4 Develop a Model and Identify Data Gaps 108

7.2.5 Develop a Subsurface Exploration Program 109

7.3 Chapter Recap 117

References 119

Index 121