An advanced UH model for unsaturated soils

In this paper, suction stress is introduced into the isotropic normal compression equation of unsaturated soils, which can describe the compression behaviors of unsaturated soils from low to high stress levels. A new loading-collapse yield equation is derived, and a model for over-consolidated unsaturated soils is established via introducing UH parameter. With only nine parameters, the proposed model can describe the stress–strain behavior of unsaturated soils under normally consolidated and over-consolidated conditions, including isotropic compression characteristics, shear contraction and dilatation, strain hardening and softening, wetting–collapse, influence of stress path and critical state. The comparisons between model predictions and tests results are employed to validate the capability of the proposed model regarding reproducing the mechanical behaviors of over-consolidated unsaturated soils.