Development of a mechanistic model for hydraulic properties of natural bentonite MX-80
Numerous empirical models exist for predicting soil water retention and hydrolytic permeability of unsaturated soil or porous medium. Although it has generally been recognized that the empirical fitting parameters in these models are somehow related to soil texture, the empirical nature means that elaborate experiments must be performed for each soil to obtain values for the parameters. More importantly, empirical models do not shed insight into the fundamental physical principles that govern the processes of unsaturated flow and drainage. In addition, neither of these models account explicitly for the swelling and shrinking properties of expansive soils such as natural bentonite MX-80. In this study, we wish to collect experimental data from literature with respect to water retention and hydrolytic permeability of unsaturated bentonite. The main efforts will, then, be made on developing a double-porosity structural model to properly describe both the capillary and the adsorptive contributions to hydraulic properties of natural bentonite MX-80, by accounting for the swelling/shrinking behaviors and the effect of accessory minerals.
Assoc. Prof. Longcheng Liu