Modelling Contamination of Clays

Abstract 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.