A Master of Science Thesis in Civil Engineering submitted by Ehab Taher Shaheen entitled, "Effect of Crude Oil Products on the Geotechnical Properties of Sandy Soil," submitted in March 2011. Available are both soft and hard copies of the thesis.
Different regions around the world are encountering oil pollution due to many reasons such as leakage of oil due to tanker accidents, transportation on land and sea, and during the process of oil drilling. This oil spill would have a negative effect on the environment and on the ecological life and it may also change the geotechnical properties of the soil. Recently, the effects of crude oil on soil contamination have received serious attention from many researchers. Most of these researchers studied the effect of crude oil itself without taking into consideration its products. Added to that, most of these outcomes have shown contradiction in their results due the addition of crude oil to the soil. Some results showed an increase in the maximum dry density while other results indicated a decrease. Similar trend was noticed in the shear strength of soil as well. The aim of this research is to investigate the effect of crude oil products (kerosene and diesel) on some of the geotechnical properties of sand. In order to achieve the goal of this research, three different types of sandy soils were selected based on their grain size distribution. The initial physical properties of the selected soils such as optimum moisture content, maximum dry density, and shear strength, angle of internal friction, grain size distribution, and permeability were determined. A number of samples were prepared by mixing the soil with different percentages of crude oil products (kerosene and diesel) and their effects were studied by conducting different experiments such as the proctor compaction test, direct shear test and the permeability test. The results indicated that as the percentage of crude oil products increased, the angle of internal friction of the sand would decrease. An apparent cohesion was found and increased gradually as diesel and kerosene were added to the soil. The maximum increase was noticed at 8 percent of crude oil product being added. When more than 8 percent was added, less v increase in cohesion was noticed. At low normal stress, as the percentage of crude oil products in soil increased, the shear strength would increase up to a certain percent and then it decreases. At high normal stress, as the percentage of crude oil products in soil increased, the shear strength would decrease. The results indicated a decrease in permeability of all soil samples due to theaddition of diesel and kerosene. From this analysis, the behavior of soil can be understood due to contamination of poorly graded sand by crude oil products (diesel and kerosene). Mathematical correlations that predict different properties of sandy soils such as shear strength, friction angle, cohesion and permeability with reasonable accuracy were estimated by regression analysis. The significantly high coefficients of correlation values indicate that the approximation concept used for the analysis performed well for the soil samples. Coefficient of curvature, coefficient of uniformity, specific gravity, normal stress and percentage of diesel/ kerosene were used as independent variables during the analysis of the models.