poro-hypoplastic analysis of the progressive excavation of the Mol URL connecting gallery

In the framework of a Euratom research program devoted to the safety assessment of nuclear waste disposal, a numerical simulation of a gallery excavation in the Boom Clay layer at Mol (Belgium) has been performed. A special sequence of deactivation/activation of sets of elements was devised in order to model the progressive excavation and lining installation process. One difficult point had to be overcome: for a given front position, the material to be excavated cannot be defined a priori. Indeed, once the front has reached a position into the rock mass, the finite deformation process has brought some additional elements into the excavation profile. The numerical strategy developed allows to excavate these additional elements.