A thermo-elasto-plastic model for saturated clay based on concept of subloading surface

The coupled thermo-mechanical behavior of saturated clays was summarized, including the temperature effects on volume change, pore pressure, preconsolidation pressure, strength and elastic modulus. Based on the experimental results, a thermal yield surface was introduced to describe the temperature-induced reversible and irreversible volume change of saturated clay. A subloading surface model was extended to consider the temperature effects. The extended model depicted the decrease of preconsolidation pressure of overconsolidated clay and the hardening of yield surface by temperature-induced plastic strain. The model was then proved to satisfy strictly the thermodynamics. With the developed model, numerical simulations of drained heating tests, drained and undrained triaxial compression tests of clay with different over consolidation rations under different temperature were performed. The simulated results were compared with the existing test results, which showed that the model described the volume change induced by temperature change, the thermal softening effect on overconsolidated clay and thermal hardening effect of normally consolidated clay.