Thermo-Hydro-Mechanical Model for Unsaturated Clay Soils Based on Granular Solid Hydrodynamics Theory

Abstract

Starting from the thermodynamic framework of a mixture, combined with the modified soil-water characteristic curve (SWCC) model, and considering the granular-level energy dissipation caused by temperature and saturation changes, this paper presents a thermo-hydro-mechanical (THM)-coupled model for unsaturated clay soils. The THM-coupled model of unsaturated soils plays an important role in environmental geotechnical engineering. However, the physical basis of THM coupling problems has not been fully clarified. By extending granular solid hydrodynamics (GSH) theory to unsaturated soils, the constitutive relations of mean effective stress and plastic deformation can be quantitatively and theoretically determined. The model was validated by comparison with experimental data in terms of the influences of temperature and suction on compression characteristic, thermal volume change behavior, shear strength properties, and water-retention characteristics of the soil. As a result, the THM coupling behavior of unsaturated soils can be well interpreted.