Effect of Waste Engine Oil Contamination on the Geotechnical Properties of Cohesive Soils in Sulaimani City, Iraq

The effect of waste engine oil (WEO) contamination on the geotechnical properties of cohesive soils was investigated. Three cohesive soils were collected from three locations in Sulaimani City. Geotechnical laboratory tests were carried out included consistency properties, unconfined compression strength, swelling pressure, and compressibility properties for both of intact and contaminated soil samples. Various percentages (0%, 1%, 2%, 4% and 6%) of WEO were mixed with the selected cohesive soil as a simulation of the field contamination issue. The results showed that the liquid limit (LL), plastic limit (PL), plasticity index (PI) increased as the content of WEO increased, however, experienced a decrease at 1% WEO content, thereafter an increase commenced again. The values of linear shrinkage limit, unconfined compressive strength (UCS), swelling pressure (SP) and Recompression index (Cr) decreased as the content of the WEO increased. The values of compression index (Cc) also increased at 0%, 1% and 2% WEO content, after that a little increase commenced again. WEO contaminated soil requires stabilization before using it as a construction material and/or for construction projects foundations. Keywords—Waste Engine Oil, Cohesive Soils, Sulaimani City.