A state surface model of unsaturated soil considering thermal and adsorptive effects

Constructing soil water retention curve model involving thermal, mechanical, and hydraulic hysteresis is essential for accurately predicting the retention characteristics of unsaturated soils under complicated conditions. A novel model depicting the retention of capillary and adsorbed water under the impact of thermal, mechanical, and hydraulic hysteresis, has been proposed. In which, the variations of void ratio-dependent capillary water have been captured based on the incremental relationship of a three-phase porous material and an empirical relationship. The impact of temperature has been described by incorporating two distinct nonisothermal functions for the matric suctions of capillary and adsorbed water. The disparity in soil water retention curves under drying and wetting branches is illustrated by leveraging the combined effect of contact angle and entrapped air. The comparisons between the predicted and measured results showed that the new model can reasonable predict the retention behaviors of unsaturated soils under different temperature, void ratio, and drying-wetting cycles.