Instabilities in alpine permafrost: strength and stiffness in a warming regime

Instabilities in alpine permafrost: strength and stiffness in a warming regime

Imprint

Foreword

Acknowledgements

Contents

Kurzfassung

Abstract

1 Introduction

1.1 Motivation

1.2 Objectives of the thesis

1.3 Organisation of the thesis

2 Literature review

2.1 Permafrost

2.2 Frozen soil

2.3 Numerical modelling

2.4 Concluding remarks

3 Triaxial stress path tests

3.1 Introduction

3.2 Soil component

3.3 Triaxial testing equipment

3.4 Triaxial test programme

3.5 Axial compression: CRS tests

3.6 Axial compression: CSC tests

3.7 Axial extension: CRS tests

3.8 Lateral compression: CSR tests

3.9 Lateral extension: CSR tests

3.10 Discussion

3.11 Summary

4 Laboratory testing

4.1 Introduction

4.2 Triaxial tests in AC on unfrozen soil specimens

4.3 Three-point bending test

4.4 Four-point bending test

4.5 Determination of unfrozen water content

4.6 Determination of thermal conductivity

4.7 Micromechanical investigation

4.8 Summary

5 Synergistic learning from laboratory tests

5.1 Unfrozen water

5.2 Ductile and brittle behaviour

6 Numerical Modelling

6.1 Introduction

6.2 Governing equations

6.3 Input parameters

6.4 Soil model

6.5 Results

6.6 Summary

7 Summary, conclusions and recommendations

7.1 Summary and conclusions

7.2 Recommendations for future research

8 References

Appendix A: Results of CRS tests in axial compression

Appendix B: Results of CSC tests in axial compression

Appendix C: Results of CRS tests in axial extension

Appendix D: Results of CSR tests in lateral compression

Appendix E: Results of CSR tests in lateral extension