Effects of Gasoil Contamination on Geotechnical Properties of Kaolinite Soils

The contamination of soils and groundwater by toxic and/or hazardous organic pollutants is a widespread environmental problem. One group of these contaminants is petroleum products. Soil pollution caused by petrochemical activities, oil spills and leakage is not only an environmental issue but also a geotechnical issue. Physical and chemical reactions between soil and contaminant lead to change in soil properties and behaviour. In this paper, a set of laboratory tests including the direct shear test, uniaxial compression test, Atterberg limits and Scanning Electron Microscope (SEM) have been carried out on Kaolinite samples polluted with different percentages of gasoil. The direct shear test results demonstrate that increasing the pollutant percentage leads to an increase of cohesion and a decrease in internal friction angle of the soil. Also, increasing the amount of gasoil to a certain percentage results in a decrease in the uniaxial strength and the plasticity index of the soil.