In this study, a novel constitutive model accounting for two-way coupled hydro-mechanical behavior of unsaturated soils including hydraulic hysteresis is proposed. On the mechanical side, elasto-plastic behavior is governed by the classical plasticity framework yielding the stress-strain relationship, whereas on the hydraulic side, water retention behavior is governed by the soil-water characteristic curve incorporating the irreversible volumetric deformations due to wetting-drying cycles. The model parameters introduced into the theoretical framework of the model for characterizing the hydro-mechanical behavior are measured directly from classical and unsaturated triaxial tests. Subsequently, predicted model results in terms of isotropic compression are calibrated with a set of suction-controlled drained triaxial tests. The proposed model contributes to enhancing our knowledge on fully coupled hydro-mechanical behavior of unsaturated soils. 

To be presented at the 20th Int. Conference on Soil Mechanics and Geotechnical Engineering, Sydney-Australia