ELASTO-PLASTIC CONSTITUTIVE MODEL FOR UNSATURATED SOIL APPLIED EFFECTIVE DEGREE OF SATURATION AS A PARAMETER EXPRESSING STIFFNESS

Abstract

To predict the long term elasto-plastic behavior of unsaturated earth structures, the constitutive model, which can express the following typical behavior of unsaturated soil, is needed. One is shrinkage and stiffness increase due to suction increase, second one is collapse with stiffness decrease due to suction decrease, and the last one is the influences of suction history relating to the hysteresis of soil-water retention characteristics. In this study, a constitutive model of unsaturated soil applied the effective degree of saturation as parameter expressing stiffness was proposed. The model showed good agreement with the experimental results and the appropriateness of the model was demonstrated.