Shear Strength and Stress-Strain behavior of Contaminated Soils

A series of unconfined compression tests performed on fine-grained soils contaminated with varying amounts of chemicals showed a decrease in shear strength and stress-strain behavior. These observations were attributed to changes in dielectric constant and pore fluid viscosity. Consolidated drained triaxial tests performed on a granular soil showed a similar behavior, even though granular soils do not show a physicochemical interaction between soil and pore fluid. This is attributed to mechanical interactions at particle contacts, caused by enhanced lubrication by viscous pore fluids. For fine-grained soils, the observed reduction in shear strength is attributed to physicochemical effects caused by a reduction in dielectric constant and mechanical interactions caused by high pore fluid viscosities. Observations show that the reduced physicochemical interactions seem to have been overshadowed by mechanical interactions. The clayey silt tested showed a marginal reduction in shear strength, indicating that the net effect is insignificant.