Table of Contents |
1. | Introduction | 1 |
1.1. | Research Status | 3 |
1.1.1. | The Study on Soil Structure | 3 |
1.1.2. | The Study on Vehicle Vibration Loading | 3 |
1.1.3. | Dynamic Response of Vehicle Vibration Load | 6 |
1.1.4. | Dynamic Properties of Soft Clay Soil Under Dynamic Loading | 10 |
1.1.5. | Microstructure of Soft Clay Soil | 13 |
1.1.6. | The Long-Term Settlement of Soft Clay Foundation Under Vehicle Vibration Loading | 16 |
1.2. | Research Content and Methodology | 18 |
1.2.1. | Dynamic Response of Soft Clay Surrounding Subway Tunnel to Subway Traffic Loads | 19 |
1.2.2. | Dynamic Characteristics of Soft Clay Under Subway Vibration Loads | 19 |
1.2.3. | Microstructure Study of Soft Clay Under Subway Vibration Loads | 19 |
1.2.4. | Numerical Simulation | 20 |
1.2.5. | Settlement Prediction of Soil Surrounding Subway Tunnel Under Subway Vibration Loads | 20 |
| References | 20 |
2. | Field-Tests | 25 |
2.1. | Introduction | 25 |
2.2. | Engineering Geology of Soft Soil in Shanghai | 26 |
2.3. | Program Design | 28 |
2.3.1. | Selection of Testing Site | 28 |
2.3.2. | Selection of Testing Instruments | 28 |
2.3.3. | Stratigraphic Section and Instrument Installation | 29 |
2.4. | Results and Analysis | 29 |
2.4.1. | Soil Response Frequency | 30 |
2.4.2. | The Attenuation of Dynamic Response in Perpendicular Direction to Subway Tunnel Axis | 32 |
2.4.3. | The Dynamic Response Development Along the Depth | 34 |
2.4.4. | Development of Pore Pressure | 35 |
2.4.5. | Mechanism Analysis of Pore Pressure Development Under Subway Traffic Loading | 36 |
2.5. | Chapter Summary | 38 |
| References | 38 |
3. | Laboratory Tests | 41 |
3.1. | Introduction | 41 |
3.2. | Pore Pressure Development | 42 |
3.2.1. | Experimental Summary | 43 |
3.2.2. | The Pore Water in Soft Clay | 49 |
3.2.3. | The Pore Water Development Properties | 53 |
3.2.4. | The Pore Water Pressure Attenuation Properties | 58 |
3.2.5. | The Mechanism Analysis of Influence of Subway Vibration Loads on Pore Water Pressure | 59 |
3.3. | Deformation Characteristics of Saturated Soft Soils | 60 |
3.3.1. | Experimental Introduction | 61 |
3.3.2. | The Factors on Deformation Under Cyclic Loads | 65 |
3.3.3. | Summary | 70 |
3.4. | Strength Characteristics of Saturated Soft Soils | 71 |
3.5. | Creep Behavior of Soil Under Cyclic Loading (Tang et al. 2010) | 72 |
3.5.1. | Test Apparatus and Samples | 74 |
3.5.2. | Test Control Parameter and Procedures | 74 |
3.5.3. | Test Procedures | 75 |
3.5.4. | Composition of Clayey Creep Under Cyclic Loading | 76 |
3.5.5. | The Change of Reversible Elastic Strain of Saturated Clay | 81 |
3.5.6. | Variation of Accumulated Plastic Strain of Saturated Clay | 83 |
3.5.7. | Variation of the Residual Pore Water Pressure | 85 |
3.5.8. | Summaries | 86 |
3.6. | Dynamic Stress-Strain Relationships | 87 |
3.7. | Effective Principal Stress Variation | 90 |
3.7.1. | Experimental Introduction | 90 |
3.7.2. | The Variation of Effective Primary Stress with Loading Time | 92 |
3.7.3. | The Variation of Shear Wave Velocity | 95 |
3.8. | Mechanism Analysis | 95 |
3.9. | Chapter Summary | 97 |
| References | 98 |
4. | Research of Microstructure | 101 |
4.1. | Introduction | 101 |
4.2. | Qualitative Analysis | 104 |
4.2.1. | Research Method | 106 |
4.2.2. | Preparation of Samples | 107 |
4.2.3. | Basic Characteristics of the Soil Samples | 108 |
4.2.4. | Qualitative Analysis of Observed Result | 109 |
4.3. | Quantitative Analysis | 126 |
4.3.1. | Research Method | 127 |
4.3.2. | Fractal Parameters of MIP Results | 131 |
4.3.3. | The Characteristics of Pore Variation in Undisturbed Soft Clay During the Process of Mercury Intrusion | 132 |
4.3.4. | The Characteristics of Pore Variation in Undisturbed Soft Clay During the Process of Mercury Extrusion | 135 |
4.3.5. | The Variation of Pore Structure Characteristic Parameters in Saturated Soft Clay Under Vibration Loading | 136 |
4.3.6. | Fractal Model and Fractal Dimension | 140 |
4.4. | Correlation Analysis Between Microstructure and Macroscopic Deformation Properties of Saturated Soft Clay Under Subway Loading | 147 |
4.4.1. | Correlation Analysis of Pore Microstructure Parameter and Macroscopic Force | 147 |
4.4.2. | Correlation Analysis of Pore Microstructure Parameters and Macroscopic Deformation | 149 |
4.5. | Chapter Summary | 151 |
| References | 152 |
5. | Finite Element Modeling | 155 |
5.1. | Introduction | 155 |
5.2. | Finite Element Analysis Software | 156 |
5.2.1. | Numerical Method | 156 |
5.2.2. | The Finite Element Method and ANSYS | 156 |
5.3. | Theoretical Analysis | 157 |
5.3.1. | General Equations of the Dynamic Analysis | 158 |
5.3.2. | Dynamic Finite Element Analysis | 161 |
5.3.3. | Static-Dynamic Analysis of Subway-Soil System | 166 |
5.4. | Simulation of the Dynamic Loading Induced by the Subway Train | 169 |
5.4.1. | Generation Mechanism | 170 |
5.4.2. | Simplified Model for Subway Train | 173 |
5.4.3. | The Simulation of Subway Train Loading | 173 |
5.5. | Model Development | 177 |
5.5.1. | Introduction to the Model | 177 |
5.5.2. | Mesh Generation in FEM Model | 179 |
5.5.3. | Material Parameters | 184 |
5.6. | Viscoelastic Artificial Boundary | 184 |
5.7. | The Time Integral Step | 186 |
5.8. | The Results of Transient Analysis | 186 |
5.9. | Chapter Summary | 189 |
| References | 190 |
6. | Settlement Prediction of Soils Surrounding Subway Tunnel | 191 |
6.1. | Introduction | 191 |
6.2. | Analysis on Subway Tunnel Settlement During Tunneling in Soft Soil | 192 |
6.2.1. | Factors | 192 |
6.2.2. | Scope of Settlement and Settlement Tank | 194 |
6.2.3. | Relationship Between Settlement and Grouting Quantity | 195 |
6.2.4. | Estimation of the Ground Pre-settlement | 198 |
6.2.5. | Summary of Early Settlement's Analysis | 200 |
6.3. | Analysis of Long-Term Settlement of Subway Tunnel in Soft Soil | 200 |
6.3.1. | Factors Affecting Long-Term Settlement of Subway Tunnel in Soft Soil | 200 |
6.3.2. | Mechanism Analysis of Long-Term Additional Settlement in Foundation Caused by Subway Load | 202 |
6.4. | Applications of Gray Prediction Theory in Predicting Long-Term Settlement of Subway Tunnel | 203 |
6.4.1. | Research Backgrounds and Introduction | 203 |
6.4.2. | Methodology of Gray Prediction Theory | 206 |
6.4.3. | Model Checking | 209 |
6.4.4. | Applications of Prediction Model | 210 |
6.4.5. | Discussions and Error Analyses | 213 |
6.5. | Effective Stress Analysis of Long-Term Settlement in Tunnel | 219 |
6.6. | Chapter Summary | 221 |
| References | 222 |
7. | Conclusions and Prospects | 225 |
7.1. | Conclusions | 225 |
7.2. | Prospects for Further Study | 228 |
| Appendix: Major Published Works of the Book Author | 229 |
| Index | 239 |