Modeling fully coupled hydraulic-mechanical-chemical processes in a natural clay liner under mechanical and chemico-osmotic consolidation.

Clayey material that possesses semipermeable membrane property may experience osmotic consolidation in presence of an osmotic gradient. In this paper, a fully coupled H-M-C model has been presented to study solute transport under the combined influence of mechanical and osmotic consolidations and vice versa. The model has been tested against the results of relevant importance and good agreements have been achieved. The model has been applied to investigate long-term solute transport behavior and consequent deformations/settlements in a natural clay liner. The results suggest, at early stages, solute transport is dominated by mechanical consolidation; however, physicochemical interaction associated with osmotic processes and osmotic consolidation dominates in the long term. Osmotic settlement shows decreasing trend past the maximum deformation of the clay liner indicating reduction of osmotic gradient across the semipermeable membrane. It is also evident that overall soil consolidation and transport of solute are affected by the concentration of the solute at the source or the injection boundary.