Pore Fluid Effects on Engineering Behavior of Clay Soils

Abstract

In recent years, the contamination of subsurface soils and groundwater from landfills, industrial activities, and other sources has been receiving more attention and has created an urgent need to find feasible solutions to the problem. In this regard, examining the influence of chemical contaminants on geotechnical properties of clays and understanding the underlying mechanisms is important. In order to define the effects of organic liquids on clay soil, ethylene glycol which is generally found in petroleum contaminated sites was selected in this study. Ethylene glycol, with a medium dielectric constant of 37.7 was mixed with different percentages by the volume of distilled water and used in geotechnical tests. Atterberg limit tests were performed in order to determine the effect of different percentages of ethylene glycol on consistency of the soil. Swelling tests were also performed to evaluate the changes in the swell potential of the clay soil permeated with different percentages of ethylene glycol. Results of the investigation indicated that increase in the concentration of pore fluid resulted in a decrease in the dielectric constant which conduced to a decrease in the diffuse double layer thickness. Depression of the diffused double layer resulted in a decrease in the plasticity of the soil and hence decrease in the swelling potential of the soil was observed. Test results showed that organic chemicals caused less heaving in soils compared with distilled water.