Title: Unsaturated Soils: A fundamental interpretation of soil behaviour Edition: 1
Author(s): E. J. Murray and V. Sivakumar
Publisher: Wiley-Blackwell
Year: 2010
Pages: 304
ISBN: 1444332120; 9781444332124
English
An understanding of the mechanical properties of unsaturated soils is crucial for geotechnical engineers worldwide, as well as to those concerned with the interaction of structures with the ground. This book deals principally with fine-grained clays and silts, or soils containing coarser sand and gravel particles but with a significant percentage of fines.The study of unsaturated soil is a practical subject, linking fundamental science to nature. Soils in general are inherently variable and their behaviour is not easy to analyse or predict, and unsaturated soils raise the complexity to a higher level. Even amongst practicing engineers, there is often lack of awareness of the intricacies of the subject. This book offers a perspective of unsaturated soils based on recent research and demonstrates how this dovetails with the general discipline of soil mechanics.Following an introduction to the basic soil variables, the phases, the phase interactions and the relevance of soil structure, an
up-to-date review of laboratory testing techniques is presented. This includes suction measurement and control techniques in triaxial cell testing. This is followed by an introduction to stress state variables, critical state and theoretical models in unsaturated soils. A detailed description of the thermodynamic principles as applied to multi-phase materials under equilibrium conditions follows. These principles are then used to explore and develop a fundamental theoretical basis for analysing unsaturated soils. Soil structure is broken down into its component parts to develop equations describing the dual stress regime. The critical state strength and compression characteristics of unsaturated soils are examined and it is shown how the behaviour may be viewed as a three-dimensional model in dimensionless stress-volume space. The analysis is then extended to the work input into unsaturated soils and the development of conjugate stress, volumetric and strain-increment variables. These are used to examine the micromechanical behaviour of kaolin specimens subjected to triaxial shear strength tests and lead to observations not detectable by other means.Unsaturated Soils: A fundamental interpretation of soil behaviour covers a rapidly advancing area of study, research and engineering practice and offers a deeper appreciation of the key characteristics of unsaturated soil. It provides students and researchers with a framework for understanding soil behaviour and demonstrates how to interpret experimental strength and compression data.provides engineers with a deeper appreciation of key characteristics of unsaturated soilscovers a rapidly advancing area of study, research and engineering practiceprovides students and researchers a framework for understanding soil behaviourshows how to interpret experimental data on strength and compressionthe limited number of books on the subject are all out of date
Unsaturated Soils......Page 5 Contents......Page 7 Preface......Page 10 Acknowledgements......Page 12 Introduction......Page 13 Symbols......Page 15 1.1 Nature and genesis of unsaturated soils......Page 21 1.2 Soil variables......Page 23 1.3 Particle properties......Page 27 1.4 Phase properties and interactions......Page 29 1.5 Soil structure......Page 42 1.6 Experimental techniques for examining pore size distribution......Page 43 1.7 Pore size distribution......Page 45 1.8 Conclusions......Page 52 2.1 Introduction......Page 54 2.2 Techniques for measurement of suction......Page 55 2.3 Control of suction in laboratory tests......Page 72 2.4 Conclusions......Page 76 3.1 Introduction......Page 77 3.2 Material selection and specimen preparation......Page 78 3.3 Experimental techniques for volume change and strength measurements......Page 84 3.4 Essential measurements......Page
89 3.5 Further details of triaxial and stress path testing techniques......Page 91 3.6 Conclusions......Page 105 4.1 Introduction......Page 107 4.2 Stresses in soils......Page 108 4.3 Strains in soils......Page 110 4.4 Constitutive modelling......Page 112 4.5 Critical state framework for saturated soils......Page 118 4.6 The constitutive Barcelona Basic Model for unsaturated soils......Page 127 4.7 Extended constitutive and elasto-plastic critical state frameworks for unsaturated soils......Page 132 4.8 Concluding remarks......Page 144 5.1 Introduction......Page 147 5.2 Outline of thermodynamic principles and systems......Page 148 5.3 Introduction to equilibrium and meta-stable equilibrium......Page 149 5.4 Variables of state......Page 150 5.6 The laws of thermodynamics......Page 151 5.7 Thermodynamic potentials......Page 155 5.8 Thermodynamic potentials in practice......Page 158 5.9 Conjugate thermodynamic pairings......Page 162 5.10 Influence of a gravitational field......Page 164 5.11 Concluding remarks......Page 165 6.2 The minimum principles for the potentials......Page 167 6.3 Isotropic loading conditions......Page 169 6.4 Anisotropic loading conditions......Page 172 6.5 Work input and the thermodynamic potential......Page 175 6.6 The thermodynamic potential and axis translation......Page 176 6.7 The thermodynamic potential and an aggregated soil structure......Page 177 6.8 Conclusions......Page 178 7.2 Role of enthalpy......Page 180 7.3 Enthalpy and Terzaghi’s effective stress for saturated soils......Page 182 7.4 Enthalpy of unsaturated soils......Page 183 7.5 The significance of α......Page 187 7.6 Stress state in unsaturated soils......Page 191 7.7 Alternative equilibrium analysis......Page 192 7.8 Graphical representation of stress state in unsaturated soils......Page 193 7.9 Stress state variables and conjugate volumetric variables......Page 194 7.10 Hysteresis, collapse and discontinuities in soil behaviour......Page 196 7.11 Conclusions......Page 199 8.1 Introduction......Page 200 8.2 Shear strength and critical state characteristics of unsaturated soils......Page 201 8.4 Compression and critical state characteristics of unsaturated kaolin......Page 220 8.5 Modelling of unsaturated kaolin......Page 226 8.6 Structure, variables and parameters......Page 228 8.7 Conclusions......Page 230 9.2 Work input under triaxial stress conditions......Page 233 9.4 Work input to unsaturated soils......Page 238 9.5 Analysis of the mobilised stress ratios......Page 240 9.6 Continuity relationships between strain-increments......Page 241 9.7 Stress state variables and conjugate volumetric and strain-increment variables......Page 243 9.8 The meaning and interpretation of stresses and strains......Page 244 9.9 Analysis of triaxial experimental data on kaolin......Page 252 9.10 Conclusions......Page 271 References......Page 274 Index......Page 293
