A constitutive model for unsaturated soils based on the modified ISMP

This paper aims to present a constitutive model for unsaturated soils, which will explain not only deformation and failure under general stress state but also deformation in collapse, based on the concept of the "Modified ISMP". In this model, we propose yield curves in isotropic stress state, which mean increase in stiffness of soil skeleton induced by increase of suction, and a yield surface which is defined by the condition of a constant plastic work. Two kinds of suction controlled tests are performed on a compacted clay. And it is shown that the deformation in triaxial compression and extension tests under a constant suction and the collapse in wetting test under isotropic stress state agree with the prediction by the proposed model.