A damaged visco-plasticity model for pressure and temperature sensitive geomaterials

This study is primarily intended to describe the behaviour of non-associated geomaterials within the framework of thermodynamics. By postulating a free energy and a dissipation function, a pressure dependent constitutive model is derived. The model is then used to solve a coupled temperature-displacement problem where shear heating feedback, multiple creep mechanisms and their induced continuum damage are included. The results show that the frictional behaviour of geomaterials in the crust has a high influence on faults orientations. In addition, the model reveals that damage nucleates in the viscous temperature-sensitive lower crust.