Abstract
This study presents the effect of Kawergosk refinery waste oil on the geotechnical properties of Erbil clayey soils. A comparison of laboratory test results on uncontaminated clayey soils has been presented and examined. Refinery waste oil of Kawergosk (20 km west of Erbil city) was chosen as the contaminant. A disturbed soil samples were collected from the site which are remolded in the laboratory before each test to represent the field dry density (1.4 gm/cm3, 5.6% water content). Laboratory investigations were carried out on soil samples with 5%, 10%, 15%, and 20% of the waste oil, the results showed a considerable effect on the chemical soil characteristics, while a slight increase of the values of Atterberg limits was observed. A considerable effect on the values of one-dimensional consolidation test parameters has also been observed; the same observation has been seen for the values of direct shear test parameters. A reduction on the values of conductivity coefficient, K has been noticed with increase of contaminated percentage.