Modelling Hydro-Mechanical Interactive Behaviour of Unsaturated Soils

Abstract

This paper presents an alternative approach for interpreting unsaturated soil behaviour, which is built in the space of stress versus degree of saturation. A new volume change equation is proposed in terms of stress and degree of saturation, to give a better explanation to the non-linear change of soil compressibility under constant suctions. An alternative approach to simulate hydraulic hysteresis and hydro-mechanical interaction is then introduced, which enables the calculation of the effective degree of saturation under complex stress and suction paths. The loading-collapse yield surface is derived based on the proposed volume change equation in the plane of the effective degree of saturation and the Bishop effective stress. The proposed volume change equation and the corresponding yield surface are generalized to three-dimensional stress states by incorporating with the Modified Cam-clay model. The proposed model is validated against a variety of experimental data in literature.