3D Modelling of Excavation-Induced Anisotropic Responses of Deep Drifts at the Meuse/Haute-Marne URL

Understanding the excavation-induced fractured zone (EFZ) around drifts is paramount in context of deep geological disposal for nuclear waste since fractures can introduce pathways migration radionuclides. Drifts Meuse/Haute-Marne Underground Research Laboratory (URL) have been essentially excavated following two main directions major and minor horizontal stresses. Field observations on GCS (parallel to stress direction) GED URL show anisotropic shapes EFZ through both orientations convergences. These responses resulted from inherent and/or induced anisotropies host rock as well field. This study focuses 3D numerical modelling including shape extent EFZ, short-term convergences drifts. The assumption that failure claystone material due fracturing along weakness planes (ubiquitous joints) matrix. ubiquitous joint represented by perfectly plastic models tensile shear yield functions. Their orientation determined state based fracture mechanics, which includes tensile, longitudinal splitting (conjugate planes) cracks. matrix assumed be elastoplastic with hardening, softening residual behaviours. Confining pressure dependency post-peak behaviour a brittle–ductile transition taken into account proposed model implemented commercial software FLAC3D. features are shown simulation laboratory triaxial compression tests, field observation within URL. In particular, comparisons between simulations situ shows promising results, demonstrates advances present respect existing models. •3D excavation mechanical COx claystone. •A coupling fracturing. •Stress controlling plane occurring its orientation. •Galleries Andra considered. •Convergence damage rather reproduced model.