Hydro-mechanical modelling of MX-80 bentonite: One dimensional study

Abstract

As a first step towards modelling the coupled Thermo-Hydro-Mechanical-Chemical (THMC) behaviour of bentonite, the Barcelona Basic Model (BBM) has been implemented into Numerrinfinite element code. This model has beenfully coupled with the single phase flow equation for unsaturated soils which models liquid water transport. Suction obtained from solving the flow equation is used as an input for the BBM model and the volumetric deformations from the mechanical analysis are used to update the pore water pressure field. As an alternative, BBM is used alongside the Kröhn's model which assumes that bentonite re-saturation is mainly driven by water vapour diffusion. The paper simulates one dimensional infiltration test on MX-80bentonite with both implemented modelsfor water transport and compares the results withthose from a laboratory experiments based on X-ray tomography. The numerical results of the simulations are similar despite taking into account different physical phenomena.