Capillary water retention curve and shear strength of unsaturated soils

Abstract

This paper proposes a new water retention model for unsaturated soils, which takes into account capillary condensation of adsorbed water. In this model, the degree of saturation of a soil is separated into that based on capillary water and that based on adsorbed water. Through analysis of a partially saturated two-cylinder system, a new shear strength criterion for unsaturated soils is proposed, in which only the degree of saturation based on capillary water contributes to the variation of shear strength with suction. The proposed shear strength criterion is justified against thermodynamic principles and is compared against existing criteria in the literature, which shows that it provides a much improved prediction of the experimental data for a wide range of suction values.Key words: unsaturated soils, capillary water retention, thermodynamics, shear strength.Résumé : Dans le contexte de cette étude, on propose un nouveau modèle de rétention d'eau pour les sols non saturés qui prend en compte la condensation capillaire d'eau adsorbée. Selon le modèle de rétention d'eau proposé, le degré de saturation d'un sol comporte deux composantes séparées, soit celle en fonction de l'eau capillaire et l'autre en fonction de l'eau adsorbée. Au moyen de l'analyse d'un système à deux cylindres partiellement saturé, on propose un nouveau critère de résistance au cisaillement pour les sols non saturés, selon ce critère seulement le degré de saturation en fonction de l'eau capillaire contribue à la variation de la résistance au cisaillement avec la succion. On justifie le critère de résistance au cisaillement proposé par rapport aux principes thermodynamiques. On compare le critère de résistance proposé aux critères puisés dans la littérature, ce qui démontre qu'il offre une prédiction grandement améliorée des données expérimentales, et ce, pour une vaste gamme de valeurs de succion. [Traduit par la Rédaction] Mots-clés : sols non saturés, rétention d'eau capillaire, thermodynamique, résistance au cisaillement.

A linear constitutive model for unsaturated poroelasticity by micromechanical analysis

“…Such work continued to the present day. 57,58 The purpose of the present work is not to investigate effective stress. It is aimed at developing constitutive equations for partial saturation that can be used for modeling.…”

A Fractal Model to Interpret Porosity‐Dependent Hydraulic Properties for Unsaturated Soils

“…Figure 1, a porous medium (V 0 ) contains a broad range of pore sizes, which decrease in the mean radius from r 0 to r u (u >> 1) and in pore volume from P 0 (the volume of the maximum pore) to P u (the volume of the minimum pore). e pores are further divided into two categories [46,47]: interparticle pores (including interaggregate macropores and intraaggregate micropores), which can be deformed via external loads and dewatered by the capillary process or heating, and intraparticle pores, which contain water that is strongly bounded with soil solids. Mercury intrusion porosimetry (MIP) test can be employed to determine the distribution of interparticle pores of soil [48].…”

Consolidated Undrained Triaxial Compression Tests and Strength Criterion of Solidified Dredged Materials

“…e strength properties of structured clays are different from remolded clays [11][12][13][14][15]. However, the existing strength criterions are mostly established on the basis of the properties of reconstituted soils [16][17][18][19] that cannot well reflect the influence of soil structures on the properties of structured soils [14]. It has been well reported by researchers [15,20] that the strength envelope of the natural structured sedimentary clays can be divided into two parts in terms of the structure yield stress (i.e., preyield state and postyield state).…”