Discontinuities and mechanical behavior of interfaces

Deformation localization and kinematic discontinuities in geomaterials and at soil-structure interfaces have been studied for a long time in the 3SR laboratory. These fine structures have a strong impact on the mechanical and hydraulic behavior of their environment on a larger scale. The stakes are high in the field of risks (unstable massifs and slopes, structures in critical or damaged sites), civil engineering design (soil-structure interaction, extreme stresses), energy and the environment (oil reservoirs, underground storage of final waste, geothermal energy...). Our work concerns both fundamental and finalized problems, and relates to incipient and/or pre-existing discontinuities:

• Development of shear bands in geomaterials and post-localized behavior: experimental tools are developed to characterize shear bands using 2D and 3D image correlation field measurements (biaxial soil, biaxial and true triaxial rock apparatus, generalized 1γ2ε shear machine, beam testing in our x-ray tomograph). From a theoretical perspective, these bands are analyzed as a bifurcation problem. The numerical treatment of post-localized boundary problems is based on enriched continuum media.
• Behavior of pre-existing interfaces: our experimental tools are used to characterize soil/structure interfaces (calibration chamber, tests in our x-ray tomograph) or rock/structure, as well as rock joints (BCR3D shear box). Our modeling work ranges from the scale of interfaces (interface laws) to that of fractured structures and rock masses.