Coupled elastoplastic damage modeling of anisotropic rocks

A coupled elastoplastic damage model is proposed for the description of strongly anisotropic sedimentary rocks. In order to describe the inherent anisotropy of the material, a scalar anisotropy parameter is introduced using the concept of fabric tensor. Using this parameter, an anisotropic plastic model is formulated taking into account influence of loading orientation. Plastic deformation is then coupled with induced damage by growth of microcracks. The proposed model is applied to typical sedimentary rock; Tournemire shale. The procedure for model’s parameters identification is presented. A series of numerical simulations are performed for triaxial compression tests performed with different confining pressures and various loading orientations. Comparisons between numerical predictions and experimental results show that the proposed model is capable to reproduce the main features of mechanical behavior of strongly anisotropic rocks.