Abstract：The present study aims to establish a homogenization-based constitutive thermodynamic framework for the description of anisotropic damage by mesocracking. With the help of the basic solution to Eshelby¢s matrix- inclusion problem，a new micromechanics-based damage-friction coupled model is developed for rock materials，which are considered here as heterogeneous solids composed of elastic solid matrix and imbedded penny-shaped microcracks. From mesomechanical analysis，the general form of the macroscopic free energy is obtained，from which the conjugated thermodynamic forces are derived within the standard thermodynamic framework. Further，similar to classic plasticity theory，a Coulomb-typed interfacially frictional sliding criterion at mesoscopic scale is used as loading function and as commonly；a non-associated flow rule is adopted in determination of the evolution rate of friction-induced inelastic deformation. The proposed model has the ability of taking into account the main phenomena due to microcracking such as nonlinear stress-strain relations，damage induced anisotropic behaviours，coupling between damage and friction on cracks surfaces，sensitivity of mechanical responses to confining pressures，volumetric dilation as well as unilateral effects due to total or partial closure of microcracks，etc.. In order to illustrate the predictive ability of the proposed model，comparisons are performed between the model predictions with experimental data from conventional triaxial compression tests on a marble. The results show a generally good agreement；and the validation of the proposed mesomechanics-based damage model is checked.
