A thermo-poro-elastoplastic constitutive model for geomaterials

In this paper, an elastoplastic formulation, coupled with the degradation of stiffness and strength of the material, is proposed to describe the thermo-mechanical behaviour of rocks. Using the effective stress principle, the constitutive relations governing the undrained response of saturated rocks subjected to heating are derived. The build-up of pore fluid pressure due to heating, leading to material failure, can be simulated by the proposed formulation. Thermo-mechanical effects on borehole stability in saturated rocks during drilling are also discussed.