Fracturing process in an anisotropic layered geomaterial: theoretical and computational predictions

The present work investigates the fracturing behavior of an anisotropic layered geomaterial, known as Opalinus Clay (OPA). The formation of this rock is mainly related to a sedimentation process, where bedding planes correspond to planes of isotropy. OPA is here studied because of its good properties, primarily, the low permeability and high adsorption capability, which make it a perfect candidate for the storage of radioactive waste. The characterization of this rock takes place experimentally in the Mont Terri Rock Laboratory, in the northern Switzerland, with an increased attention to theoretical and computational predictions. In this context, this work aims at simulating the nonlinear crack behavior of OPA by using the eXtended Finite Element Method (XFEM) and damage mechanics. The study is applied on a Semi-Circular specimen under a Bending load (SCB), whose fracturing response is investigated in terms of peak load and direction of the cracking propagation for different notch dimensions and geometries.