Modelling contamination of clays

A constitutive model for the behaviour of clays in contact with organic liquids is presented. The model was originally proposed by Hueckel (1997), based on experimental data reported by Fernandez and Quigley (1985,1991). It is recognized that the physico-chemical phenomena taking place at the scale of the clay particles are responsible for changes in permeability and deformation in the clay. Two types of chemical strains are identified: an elastic expansive strain at stress level lower than the plastic yield limit, and a plastic compaction strain at higher stress level. The plastic yield limit is assumed to decrease as the contaminant mass concentration increases. This is referred to as chemical softening. The chemo-plastic behaviour of a cylindrical clay layer subjected to vertical flow of contaminant is simulated. © 2004 Elsevier Ltd. All rights reserved.