低塑性粉土剪切与动力行为

Contents
1 Introduction 1
1.1 Definition of Low-plasticity Silt 1
1.2 Distribution of Low-plasticity Silt 1
1.3 Research Significance 2
1.4 Research Background 4
1.4.1 Soil Specimen Preparation for Laboratory Testing 4
1.4.2 Monotonic Shear Behavior of Low-plasticity Silt 6
1.4.3 Liquefaction of Low-plasticity Silt 8
1.4.4 Postcyclic Compressibility of Low-plasticity Silt 9
1.4.5 Postcyclic Shear Behavior of Low-plasticity Silt 10
1.4.6 Effect of Cyclic Loading Magnitude on Static Behavior 11
1.4.7 Reliquefaction Characteristics 14
1.5 Soil Material Tested in This Study 16
1.6 Scope of This Book 17
References 18
2 Preparation Approach of Low-plasticity Silt Specimens for Triaxial Testing 23
2.1 Specimen Reconstitution 23
2.1.1 Reconstitution Procedures 23
2.1.2 Specimen Uniformity 25
2.2 Specimen Preparation for Testing 27
2.2.1 Specimen Movement 27
2.2.2 Disturbance During Handling and Moving of the Specimen 29
2.3 Replication 31
2.3.1 Monotonic Triaxial Tests 31
2.3.2 Cyclic Triaxial Test 31
2.4 Summary 34
References 34
3 Monotonic Shear Behavior of Low-plasticity Silt and Its Change with Soil Plasticity 35
3.1 Testing Program 35
3.2 Monotonic Shear Behavior of Low-plasticity Silt 38
3.2.1 Stress-Strain Behavior of Low-plasticity Silt 38
3.2.2 Effective Friction Angle 39
3.2.3 Critical State 42
3.3 Normalized Behavior of Low-plasticity Silt 44
3.4 Effect of Plasticity Index on Silt Behavior 49
3.4.1 Stress-Strain Behavior of Silt-Bentonite Mixture 49
3.4.2 Undrained Shear Strength 52
3.5 Discussion 54
3.6 Summary 55
References 56
4 Liquefaction Characteristics of Low-plasticity Fine-Grained Soil 59
4.1 Testing Program 59
4.2 Cyclic Behavior of Low-plasticity Silt 60
4.2.1 Effect of Initial Consolidation Conditions 60
4.2.2 Effect of Plasticity 62
4.3 Reexamination of Laboratory Data 69
4.3.1 Collection of Laboratory Data 69
4.3.2 Variation of Liquefaction Resistance with Plasticity Index 71
4.3.3 Potential Application 75
4.4 Summary 78
References 78
5 Postcyclic Compressibility of Low-plasticity Silt 81
5.1 Testing Program 81
5.2 Permeability 82
5.3 Compression and Recompression Indices 84
5.4 Magnitude of Compressibility After Liquefaction 85
5.5 Effect of Plasticity on Postcyclic Compressibility 87
5.6 Summary 87
References 89
6 Postcyclic Shear Behavior of Low-plasticity Silt 91
6.1 Testing Procedure 91
6.2 Effect of CSR on Postliquefaction Shear Behavior 95
6.3 Shear Behavior of Postcyclic Specimens with Reconsolidation 96
6.3.1 Postcyclic Undrained Monotonic Shear Behavior 96
6.3.2 Effect of OCR on Postcyclic Undrained Monotonic Shear Strength 101
6.3.3 Effect of σc on Postcyclic Undrained Monotonic Shear Behavior 102
6.4 Shear Behavior of Postcyclic Specimens without Reconsolidation 104
6.4.1 Postcyclic Undrained Monotonic Shear Behavior 104
6.4.2 Effect of OCR on Postcyclic Undrained Monotonic Shear Strength 106
6.5 Change of Critical State Line Due to Cyclic Loading 107
6.6 Effect of Reconsolidation Level on Postcyclic Behavior 109
6.6.1 Undrained Shear Behavior 109
6.6.2 Shear Strength and Stiffness 109
6.6.3 Apparent OCR 112
6.7 Effect of Plasticity on Postcyclic Shear Behavior 113
6.7.1 Stress-Strain Behavior 113
6.7.2 Shear Strength and Stiffness 115
6.7.3 Discussion 118
6.8 Summary 119
References 121
7 Effect of Cyclic Loading Magnitude on Shear Behavior of Low-plasticity Silt 123
7.1 Experimental Program 123
7.2 Effect of Excess Pore Pressure on Postcyclic Shear Behavior with Full Reconsolidation 124
7.2.1 Undrained Shear Behavior 124
7.2.2 Shear Strength and Stiffness at Small Deformation 126
7.2.3 Shear Strength and Stiffness at Large Deformation 126
7.3 Effect of Excess Pore Pressure on Postcyclic Shear Behavior-without Reconsolidation 130
7.3.1 Undrained Shear Behavior 130
7.3.2 Shear Strength and Stiffness at Small Deformation 130
7.4 Threshold Strain for Postcyclic Shear Behavior 132
7.4.1 Stress-Strain Behavior 132
7.4.2 Determination of Threshold Axial Strain 133
7.4.3 Influence Factors 136
7.5 Discussion 141
7.6 Summary 142
References 143
8 Reliquefaction Characteristics of Low-plasticity Silt 147
8.1 Testing Program 147
8.2 Testing Results 148
8.2.1 Excess Pore Pressure Response 148
8.2.2 Axial Strain 151
8.2.3 Liquefaction Resistance 152
8.2.4 Effect of the Level of Cyclically Induced Axial Strain 153
8.3 Discussion 155
8.4 Summary 156
References 156