Investigation of the Impacts of Fuel Oil on the Geotechnical Properties of Cohesive Soil

Abstract

The present study investigates the impacts of fuel oil (MFO) on the chemical, physical and mechanical properties of cohesive soil. The contaminant is fuel oil disposed as byproduct from the fuel feeding the electricity power plant at the campus of University of Baghdad in Baghdad/Iraq. The soil sample are obtained from the same site of electricity plant and classified according to unified soil classification system (USCS) as silty clay of low plasticity (CL). The soil samples are artificially contaminated with two percentages of fuel oil, 10 and 20% in relative to the dry weight of soil. The soil samples were mixed by hands with fuel oil and left for 4 days to allow chemical reactions between soil particles and contaminant. A series of laboratory tests are conducted on both intact and artificially contaminated soil samples to measure the effects of fuel oil on the chemical, physical and mechanical properties of soil samples. The results of tests showed that the fuel oil has significant impacts on the mechanical properties of soil and slight effects on the chemical and physical properties of soil. Increasing the percentage of contaminant causes a slight decrease in the liquid limit and particle size distribution, on the other hand it causes a considerable decrease in the consolidation and shear strength parameters. The results of direct shear tests showed decreasing the cohesion of soil by 44 and 67%, but the angle of internal friction decreased by 20 and 32% for soil samples contaminated with 10% and 20% of fuel oil respectively.