Micromechanical modelling of anisotropic damage in brittle rocks and application

The present study deals with the formulation of a new micromechanical model for anisotropic damage in brittle rocks and its numerical implementation and application. The basic idea is to integrate Eshelby solution-based homogenization approaches into the standard thermodynamics framework for the description of inelastic deformation contributed by microcracks; the anisotropic damage is coupled with frictional sliding which occurs on closed cracks. The identification of the micromechanical model requires only six parameters, each with a clear physical meaning. Comparisons of the model's predictions with experimental data are performed on both conventional and true triaxial compression paths, respectively, for two granites. The proposed model is implemented into the finite element software Abaqus. Its application to an underground excavation problem shows that the proposed model is able to describe general responses and damaged zone evolution due to excavation.