On the micro-scale modelling by homogenization schemes in geomechanics

The mechanical behaviors of geomaterials are significantly affected by the presence of voids or cracks-like defects. The modeling of such behavior is classically performed by considering purely macroscopic or micromechanically-based damage models. In the perspective of applications in civil engineering or in geomechanics, we propose in this paper to evaluate a homogenization approach, based on Mori-Tanaka scheme, applied to micro-cracked materials. In order to provide an appropriate interpretation of the nonlinear behavior at macro-scale, the crack-induced damage is coupled to friction phenomena on closed cracks lips. The predictions of the coupled model are first analyzed on laboratory tests performed on Callovo-Oxfordian Clay. Then, they are extended to a numerical analysis of excavation damaged zones around tunnels