An elastoplastic damage model for fractured porous media

Abstract

An elastoplastic damage model is developed for fractured porous media. The elastic–plastic response of stress–strain is captured by a bounding surface plasticity within the critical state framework, while the damage evolution due to hydro-mechanical effects is addressed using a continuum damage model that is distinguished from the existing models by accounting for the plastic hardening parameter, stress ratio, confining pressure and strain rate. The coupling between the elastic–plastic response and damage is established by accounting for the effects of plastic volumetric strain and the damage parameter on the hardening of the bounding surface. The model is applied to different rocks subjected to isotropic and deviatoric loading in drained and undrained conditions. A good agreement is obtained between the numerical and experimental results demonstrating the ability of the model to capture the essential features of deformation in fractured porous media.