The Effect of Oil Contamination on the Geotechnical Properties of Fine-Grained Soils

Abstract

Every day, petrochemical activities, oil spills, and pipeline or reservoir leakage contaminate the ground. In addition to environmental concerns, such as groundwater pollution, the alteration of geotechnical properties of the contaminated soil is also cause for worry. Contamination has been proven to alter the geotechnical properties of soil, and researchers have extensively studied the properties of contaminated granular soils. However, the effect of oil contamination on the geotechnical properties of fine-grained soils has not yet been well evaluated. Therefore, a comprehensive set of laboratory tests has been conducted on both uncontaminated and contaminated fine-grained soils containing different amounts of crude oil. The soil samples were taken from the lands in the vicinity of the Tehran oil refinery site where there is a vast area subjected to this problem. The results of this study indicated that an increase in the angle of internal friction, maximum dry density, compression index, and Atterberg limits as well as a decrease in optimum water content and cohesion occur as the oil content increases. Moreover, aging caused a further decrease in cohesion but had no specific effect on the internal friction angle. These effects should be taken into consideration in the oil refinery site development programs. In addition, because treatment technologies for site clean-up are expensive, by investigating the geotechnical properties of contaminated soil, we are planning to develop methods of utilizing the soil as construction material.