Numerical Simulation on Water Absorption by MX-80 Bentonite for Nuclear Waste Disposal

As a low permeability, high thermal conductivity and mechanical strength soil, bentonite has been widely used as buffer/backfill material for nuclear waste disposal. Underground water flow behavior in bentonite was studied in this paper. A numerical simulation was conducted to predict the water absorption test of MX-80 bentonite, which is worldwide known commercial material. ABAQUS was used for simulating the water flow in the soil column in which hydro-mechanical coupled model is taken into consideration. Darcy's law and van Genuchten soil water retention curve model were used for water flow. Ideal elastic model, Drucker-Prager plastic model and wetting expansive model were taken to describe the stress-strain relations of the soil. Comparison between experimental and simulation results shows that the proposed numerical method is reasonable to predict the water flow in MX-80 bentonite.