Modelling a hydration and heating column test on unsaturated bentonite using a double-porosity approach

A controlled re-saturation of a heated 50 cm long column made of MX-80 bentonite pellets in the CIEMAT laboratory facilities (Madrid, Spain) has been running for 10 years (2011-2021). The experimental data on the saturation state and the swelling response of the bentonite material at high temperatures provided useful information for the verification of a double-porosity approach that considers the hydro-mechanical coupling between the micro- and macro-pore levels and the definition of retention curves for each structural domain. The numerical modelling with this double-porosity model has shown to be able to reproduce the main behaviour features observed in the lab test.