Coupled Hydromechanical Modelling of a Vertical Hydraulic Sealing System Based on the Sandwich Principle

Abstract For the shaft sealing of a repository for radioactive waste, Sandwich system was developed by KIT-CMM consisting bentonite-based segments (DS) and sand mixture-based equipotential (ES). To demonstrate functionality system, various laboratory tests (MiniSandwich semi-technical scale experiments) have been carried out before large-scale experiment has implemented in situ at Mont Terri Rock Laboratory (CH). An important coupled process is swelling deformation DS while aqueous fluid penetrates into system. Consequently, interparticle porosity (effective porosity) decreases strain, resulting reduction permeability DS. Pore space ES also slightly due to stress adjacent DS, which leads ES. understand hydromechanical processes numerical model interpret experimental observations from MiniSandwich parameterize different components. A linear empirical functions deformation-induced change both were introduced with Richards’ flow elastic model. Sensitivity analysis parameter variations most parameters reduces uncertainty behavior.