Chapter1 Introduction 1
1.1 Background 1
1.2 Research Objectives 3
1.3 Outline of the Book 4
Chapter2 Literature Review 5
2.1 Introduction 5
2.2 Non-coaxiality of Soil Behaviour 5
2.2.1 Definition of Non-coaxiality 5
2.2.2 Previous Studies on Non-coaxiality 6
2.2.3 Previous Numerical Studies on Non-coaxiality 9
2.3 Hollow Cylinder Apparatus 12
2.3.1 Introduction 12
2.3.2 Principles of Hollow Cylinder Testing 12
2.3.3 Stress Distribution in Hollow Cylinder Specimens 16
2.3.4 Specimen Geometry 19
2.3.5 Membrane Penetration Errors 21
2.3.6 Previous Experimental Studies Using HCA 22
2.4 Previous Studies on Non-coaxiality of Soil Behaviour Using HCA 23
2.5 Summary 30
Chapter3 Experimental Methodology 32
3.1 Introduction 32
3.2 NCG Hollow Cylinder Apparatus 32
3.2.1 Introduction 32
3.2.2 Equipment Setup 32
3.2.3 Loading System and Measuring Instrumentation 34
3.2.4 Control Software 37
3.3 Tested Materials 38
3.3.1 Index Properties 38
3.3.2 Particle Shapes 39
3.4 Testing Procedures 40
3.4.1 Specimen Preparation 40
3.4.2 Saturation and Consolidation 43
3.4.3 Test Control 45
3.4.4 Stress Paths 46
3.5 Equipment Evaluation 48
3.5.1 Preliminary Experiments 48
3.5.2 Repeatability of Test Results 50
3.5.3 Hollow Cylinder Test Versus Triaxial Test 53
3.5.4 Membrane Penetration Error Correction 55
3.6 Summary 56
Chapter 4 Monotonic Loading Tests 58
4.1 Introduction 58
4.2 Test Details 58
4.2.1 Initial Conditions 58
4.2.2 Stress Paths 59
4.3 General Soil Behaviour 61
4.3.1 Series F-D:Dense Sand 61
4.3.2 Series F-M:Medium Dense Sand 70
4.3.3 Discussion and Comparison 78
4.4 Non-coaxial Soil Behaviour 85
4.4.1 Series F-D:Dense Sand 85
4.4.2 Series F-D:Medium Dense Sand 87
4.4.3 Discussion and Comparison 89
4.5 Summary 91
Chapter5 Pure Rotation Tests 93
5.1 Introduction 93
5.2 Testing Procedures 93
5.2.1 Testing Conditions 93
5.2.2 Stress Paths Followed 94
5.2.3 Variations of Stresses 95
5.3 Tests on Portaway Sand 98
5.3.1 General Soil Behaviour 98
5.3.2 Non-coaxial Behaviour 108
5.4 Tests on Leighton Buzzard Sand 111
5.4.1 General Soil Behaviour 111
5.4.2 Non-coaxial Behaviour 112
5.5 Comparison and Discussion 115
5.6 Summary 116
Chapter6 Combined Loading Tests 118
6.1 Introduction 118
6.2 Testing Procedures 118
6.3 General Soil Behaviour 120
6.3.1 Stress Variation 120
6.3.2 Strain Variation 121
6.3.3 Effect of Density 122
6.4 Non-coaxial Soil Behaviour 123
6.5 Comparison and Discussion 124
6.6 Summary 128
Chapter7 Summary and Conclusions 129
7.1 Summary 129
7.1.1 Background on Non-coaxiality 129
7.1.2 Reason to Study the Non-coaxial Soil Behaviour 130
7.1.3 Experimental Techniques 131
7.2 Conclusions 131
7.2.1 Behaviour Under Monotonic Loading 131
7.2.2 Behaviour Under Pure Rotation of α 132
7.2.3 Behaviour Under Combined Loading 133
7.3 Recommendations for Future Research 133
7.3.1 Update of the Experimental Techniques 134
7.3.2 Experimental Work 134
List of Tables 136
List of Figures 137
References 145