Effect of petroleum on the physical and mechanical properties of fine-grained soils of Arak Shazand refinery area

With the expansion of oil industries, the leakage of oil materials increases. In addition to the negative effects of the environment, the oil leakage causes changes in the physical and geotechnical properties of the soil. These changes in granular soils are in the form of changes in the physical properties and structure of the soil, which leads to a decrease in the bearing capacity and an increase in the settlement of the soil under the foundation. In order to investigate the geotechnical behavior of fine-grained soils due to oil infiltration, a soil sample was taken from the Shazand Arak Refinery area and mixed with 0-5-10-15-20 percent crude oil by weight and remolded with a density of 90 percent of the maximum density (Proctor method) has been subjected to various physical and mechanical tests. Of course, the plastic index has a decreasing trend with the increase of the amount of crude oil. In the compaction test, the maximum dry unit weight of the soil increases with the addition of crude oil and the optimum moisture content decreases with the increase of the amount of crude oil up to 10% and then increases. In addition, the addition of oil generally reduces the permeability coefficient of the soil. Increasing the amount of oil has a different effect on soil consolidation, and the coefficient of soil consolidation increases with increasing the amount of oil. In addition, the uniaxial compressive strength of the soil decreases with the increase of the oil content.