Thermodynamic constitutive model for non-isothermal consolidation and undrained shear behaviors of saturated soils

A non-elastic multi-field mechanical model that doesn’t require the determination of yield surface and flow rules is established based on the non-equilibrium thermodynamic approach. The concepts of dissipation forces, dissipation flows and granular entropy are introduced for describing the inter-particle movement and the resulting non-elastic energy dissipation by a group of migration coefficients and energy functions. Thus, the constitutive relations of non-elastic deformation are obtained theoretically. The physical process of bound pore water transforming into free water when the temperature rises is taken into consideration for describing the phenomenon of non-isothermal consolidation. The behaviors of non-isothermal consolidation and undrained shear tests at different temperatures for saturated clay with different over-consolidation ratios (OCR) are simulated using this model in order to validate the model. The simulated results show that the non-isothermal consolidation is OCR-dependent and irrevocable under cyclic thermal loading. The undrained shear strength is also influenced by OCR and soil types.