Abstract: The influence of temperature variation on soils’ strength and deformation cannot be neglected in geotechnical engineering, such as shallow geothermal energy extraction, nuclear waste disposal, and the construction of geothermal structures. To comprehensively describe the thermomechanical behavior of soils, a thermo-elasto-plastic model of saturated clay that incorporates the temperature effect is established based on the disturbed state concept. By considering the thermal dependence of the volumetric strains and critical state, a disturbance function is introduced to reflect the influence of overconsolidation ratio (OCR) on the strength, dilatancy and deformation of saturated clay. The disturbance function is incorporated into the dilatancy stress ratio, potential failure stress ratio, and plastic modulus. Finally, the proposed model is validated through the isotropic heating-cooling tests, temperature-controlled drained triaxial compression tests, and temperature-controlled undrained triaxial compression tests. The proposed model can properly reflect the thermal-hardening and thermal-softening behavior of the saturated clay. The strain hardening and volumetric contraction of normally consolidated clays, as well as the strain softening and volumetric expansion of overconsolidated clays under the drained condition are well captured. Meanwhile, the proposed model can describe the strength and stress paths evolution of saturated clay under the undrained condition.

Key words: saturated clay, disturbed state concept, overconsolidation, temperature, strength