Onshore and offshore oil spills contaminate soil. In addition to environmental concerns about ground water pollution and other possible effects, the geotechnical properties of the contaminated soil such as the shear strength and the hydraulic conductivity are also altered. This paper presents the results of research to evaluate the variation of the shear strength of a sand contaminated by three different types of oil with varying kinematic viscosities and thus the ultimate bearing capacity of shallow foundations. The results of the tests reported here relate to only one type of sand and three types of oil. The oil contents were varied from zero to 6%. Results of direct shear tests for determining the soil friction angles are given. Additionally, laboratory model test results to determine the ultimate bearing capacity of a surface strip foundation supported by oil contaminated sand are also presented. Based on these test results, the effect of oil contamination in drastically reducing the bearing capacity is discussed.
Every year, several onshore and offshore oil spills occur around the world, and these oil spills contaminate the soil. The physical properties of the oil-contaminated soil will also control the stability of slopes as well as the bearing capacity of foundations and other structures. During the last decade, the results of a number of studies related to the physical properties and behavior of oil and petroleum constituent-contaminated soil were published (e.g., Cook et al., 1992; Evgin et al., 1989; AI-Sanad et al., 1995, 1997; Puri et al., 1994; Fan et al., 1994; Tuncan and Parnukcu, 1992). It does however appear that further studies are necessary to quantify several parameters which are of interest to geotechnical engineers.
