Response of Callovo-Oxfordian claystone during drying tests: unsaturated hydromechanical behavior

摘要: The French National Agency for Nuclear Waste Management is currently studying the Callovo-Oxfordian claystone as a potential repository nuclear waste. This study focuses on hydromechanical (HM) unsaturated response of rock subjected to hydraulic loading. Static atmosphere drying tests highlighted HM coupling and mechanical anisotropy samples. A coupled poroelastic model was proposed, involving highly nonlinear equations. Numerical simulations were performed using finite element code Code_Aster. Through sensitivity analysis, most suitable parameters estimation found be Biot coefficient 3 4 independent Van Genuchten–Mualem relations. estimated according an inverse procedure that minimizes cost functional. estimates could not outline any hysteretic behavior, but they appeared divided into two groups (depending their fitted values). convergence stability algorithm studied, results showed direct computations must run prior inversion ensure its convergence. No plasticity occurred in samples (according model), whereas irreversible phenomena do take place situ.