Interpretations of the Mechanical Behavior of Unsaturated Soils under Triaxial Stress Conditions based on an Elastoplastic Model

Abstract

We qualitatively interpreted the typical unsaturated soil behavior under triaxial stress conditions by using the elastoplastic model for unsaturated soils proposed by Kohgo et al. which was based on the modified Cam clay model. The results of consolidation and triaxial compression tests for compacted DL clay and a mixed soil were selected as typical unsaturated behavior. In the consolidation tests, we interpreted the behavior due to increases and decreases of suction and isotropic stresses. In the triaxial compression tests for DL clay and a mixed soil under constant suctions, we discussed their shear behavior. The elastoplastic model with two suction effects; an increase of effective stresses due to suction increase and an increase in yield stress and stiffness for plastic deformation due to suction increase, could well explain the typical behavior of unsaturated soils mentioned here.