A micro-mechanics-based elastoplastic friction-damage model for brittle rocks and its application in deformation analysis of the left bank slope of Jinping I hydropower station

This study develops a micro-mechanics-based elastoplastic damage model within the framework of irreversible thermodynamics. In the model, damage is related to growth of micro-cracks, while plastic deformation is induced by frictional sliding along those cracks. The damage criterion and functions of thermodynamic force are used to describe the damage evolution of rocks and determine whether they are damaged. Time-dependent deformation of rock is also taken into account by considering subcritical growth of micro-cracks. For engineering application, the proposed model is implemented in the standard finite element code Abaqus as a user-defined material model (UMAT) by using a specific local integration algorithm. The accuracy of the proposed model is assessed by comparing numerical results with experimental data in conventional triaxial compression tests and triaxial creep tests. The proposed model is then used for simulating the displacement field, damage and plastic zones of the left bank high slope. The predicted results are in a good consistency with field monitored data.