A unified thermal-hardening and thermal-softening constitutive model of soils

Based on the modified Cam-clay model and the concept of subloading yield surface, a thermo-elastoplastic model of normally consolidated and overconsolidated soils is presented in detail. The model is able to describe the thermal-hardening and thermal-softening mechanical behavior of soils with a unified set of parameters. A thermo-induced equivalent stress is proposed to consider the effect of temperature on yield surface and evolution of overconsolidation during shearing process. At the same time, the effect of temperature on the shear stress ratio at the critical state is also implemented in the model. Through comparing the simulated results with test results under different loading and temperature conditions, the availability and the accuracy of the proposed model are carefully verified. Finally, the generating mechanism of the thermal-hardening and thermal-softening mechanical behavior of soil under non-isothermal condition is discussed based on the proposed model. (C) 2019 Elsevier Inc. All rights reserved.