Collapse Potential of Oil-Contaminated Loessial Soil (Case Study: Golestan, Iran)

Oil pollution in soils is an important problem for foundations, excavations, and slopes. Soil contamination occurs when oil leaks from storages, pipelines, petrochemical activities, etc. for so many reasons. This pollution changes geotechnical properties of soils. Researchers have tested different types of soil to assess their behavior once oil-contaminated. However, to the best of our knowledge, no study on oil-contaminated collapsible soil is published. Accordingly, the present study is an attempt to test collapse potential of these soils. Samples were tested in different saturation conditions. Saturated tests were carried out on clean soil with water, gas oil or lamp oil as pore fluid, separately. Another series of samples were partially contaminated with gas oil or lamp oil and saturated with water. Results showed that, with disturbing loess soils, collapse potential decreases even though the samples were remolded at the same void ratio as that of undisturbed samples. Saturating the samples with gas oil and lamp oil virtually disappeared collapse potential and made it to a very slight value. The samples contaminated with different gas oil and lamp oil contents showed an increase in collapse potential with increasing oil content.