ABSTRACT
A zone with significant irreversible deformations and significant changes in flow and transport properties (named Excavation Damaged Zone or EDZ) is expected to be formed around underground excavations in the deep geological layers considered for the high level radioactive waste disposal. Stress perturbations around the excavation could lead to a significant increase of the hydromechanical properties, related to diffuse and/or localized microcracks propagation in the material (Bernier et al. 2007). The modelling of such behaviour is classically performed by considering macroscopic or micromechanically-based damage models. Recent developments in the field of homogenization methods provide now physically and mathematically appropriate framework for the investigation of the behaviour of micro-cracked media including the description of damage anisotropy-induced anisotropy, as well as cracks closure effects (Zhu et al. 2008; Dormieux et al. 2006). However, in the perspective of applications to civil engineering or geotechnical problems, like underground excavations, it is desirable to evaluate the different homogenization schemes by an analysis of their assumptions and of the macroscopic response that they predict.
