Case Study on Influences of Oil Contamination on Geotechnical Properties of Coastal Sediments in The Yellow River Delta

With the process of large-scale exploitation of coastal and offshore oil, coastal soils have encountered oil pollution due to the historical waste from oil drilling, related tanker navigations and accidents in recent years. Therefore, it is important to find out geotechnical properties of oil-contaminated coastal sediments for engineering and environmental purposes. In a certain clayey beach of an oil-contaminated intertidal zone in the Hai-gang region of Yellow River Delta, some groups of coastal soil were sampled and their geotechnical properties were studied in a lab. The testing on contaminated soil samples included basic physical properties test, grain size analysis, Atterberg limits, compaction, direct shear test and a micro-structure scan. Oil content in the samples was analyzed by ultraviolet- spectrophotometer assay. The results show that heavily-polluted soil has higher clay particle content, liquid and plastic limit, and compression coefficient than light-polluted soil. Compression modulus is lower for heavily-polluted soil, while cohesion force and internal friction angle have no notable correlation with oil content. According to micro- structure scan, soil particles are finer and surrounded by oil particles in the heavily-polluted samples.