A microstructurally based effective stress for unsaturated soils
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- 1 December 2010
- journal article
- Published by Thomas Telford Ltd. in Géotechnique
- Vol. 60 (12), 913-925
- https://doi.org/10.1680/geot.8.p.002
Abstract
Current alternative choices of stress state variables in unsaturated soils are described and compared, with a special focus on the use of an effective stress. Experimental data on stiffness and shear strength evolution with suction suggest that the proportion of suction contributing to the effective stress is often much smaller than predicted by the term ‘suction times degree of saturation' generally used in effective stress expressions of the Bishop type. It is suggested that effective stress in unsaturated soils should be related to soil microstructure. An effective degree of saturation is defined as describing the volume of water partially filling the soil macroporosity. This effective degree of saturation defines the proportion of the prevailing suction that actually contributes to the effective stress. Two alternative expressions (piecewise linear and non-linear) are proposed for the effective degree of saturation. They offer a similar performance. Available data on stiffness and shear strength varia... Les différents choix de variables d'état de contrainte dans les sols non-saturés sont décrits et comparés, avec un intérêt particulier pour les approches employant une contrainte effective. Les données expérimentales relatives à l'évolution de la rigidité et de la résistance au cisaillement en fonction de la succion permettent d'affirmer que la proportion de la succion contribuant à la contrainte effective est souvent nettement moindre que ne le prédit le produit « succion par degré de saturation » généralement rencontré dans les expressions de contraintes effectives du type de celle de Bishop. Il est suggéré ici que la contrainte effective est reliée à la microstructure du sol. Un degré de saturation effectif est introduit pour décrire le volume d'eau saturant partiellement la macroporosité du sol. Ce degré de saturation effectif définit la proportion de la succion contribuant concrètement à la contrainte effective. Deux expressions alternatives (l'une linéaire par morceaux et l'autre non-linéaire) sont ...Keywords
This publication has 38 references indexed in Scilit:
- Revisiting the constitutive equations of unsaturated porous solids using a Lagrangian saturation conceptInternational Journal for Numerical and Analytical Methods in Geomechanics, 2007
- Adaptation of existing behaviour models to unsaturated states: application to CJS modelInternational Journal for Numerical and Analytical Methods in Geomechanics, 2005
- A constitutive model for unsaturated soils: thermomechanical and computational aspectsComputational Mechanics, 2004
- Finite element formulation and algorithms for unsaturated soils. Part II: Verification and applicationInternational Journal for Numerical and Analytical Methods in Geomechanics, 2003
- Finite element formulation and algorithms for unsaturated soils. Part I: TheoryInternational Journal for Numerical and Analytical Methods in Geomechanics, 2003
- An elasto-plastic model for unsaturated soil incorporating the effects of suction and degree of saturation on mechanical behaviourGéotechnique, 2003
- Micromechanics of saturated and unsaturated porous mediaInternational Journal for Numerical and Analytical Methods in Geomechanics, 2002
- Theoretical Aspects of Constitutive Modelling For Unsaturated SoilsSoils and Foundations, 1993
- The filter-paper method of suction measurementGéotechnique, 1986
- Limitations to the Use of Effective Stresses in Partly Saturated SoilsGéotechnique, 1962