Impact of Crude Oil Pollution on some Geotechnical Characteristics of North Rumaila Soils in the Southern Iraqi Province of Basrah Governorate

Background: Pollution affects the soil and results in a change in its natural, chemical, or organic characteristics and properties, which directly or indirectly affect the geotechnical properties of the soil and make it unsuitable for engineering use. The aim of the study is to determine how adding various amounts of crude oil to the study area's soil affects the soil's geotechnical characteristics, including soil shear resistance, compaction coefficients, and California bearing capacity. Materials and Methods: The North Rumaila site was chosen for the study. At a depth of one meter, natural, pollution-free soil was extracted, and weight percentages of 2%, 4%, 6%, 8%, and 10% of crude oil were added. Grain size analysis, moisture content, direct shear, compaction, and Californian bearing tests were conducted. Results: The findings indicate that the soil at the North Rumaila site has a moisture content of 6.45% and is mostly silty sand with small amounts of clay and gravel. Crude oil was added to the soil, which caused the Californian to lose some of its bearing capacity, the optimal moisture content to raise, the angle of internal friction to decrease, and the bearing capacity of the soil to decrease. Conclusion: Pollution by crude oil effects negatively impacted the soil's geotechnical qualities.