This research investigated the bearing capacity and geotechnical properties of a sandy soil substrate contaminated with oil derivatives, diesel fuel, and kerosene. For this purpose, a site with a clayey sandy soil substrate was considered to evaluate the effects of contamination on the geotechnical properties and bearing capacity of the substrate in both clean and contaminated states. Then, the substrate of the site was artificially contaminated with diesel fuel and kerosene and underwent field and laboratory tests. The experiments, including the Atterberg limits, standard proctor compaction, uniaxial compressive strength, strength, and freeze-thaw durability tests, were performed on prepared samples. Also, to determine the bearing capacity of the contaminated and intact substrates, a plate load test was conducted at the site. The results indicate that contamination by oil derivatives reduces the strength and increases the settlement and displacement of the contaminated substrate, where the effects of diesel fuel are more significant than those of kerosene. The results of this research are compared to previous studies. The literature shows that most research in this area was carried out in the laboratory, and there is a lack of in-situ studies. This study showed that the presence of oil contaminations caused a 3.5% reduction in the amount of soil Atterberg limits. The contaminations also reduced the dry density and uniaxial compressive strength of the soil by 2.5% and 20%, respectively. The results presented were consistent with the results of other researchers. However, some studies have suggested an increase in the Atterberg limits due to oil contaminants in the soil.

Spur dikes are river training structures used for prevention of erosion at river banks and cause distancing of flow from the critical zone and creation of local contraction in water flow. In the present study, 2D modeling of the flow pattern around a spur dike in a straight canal with 6m length and 0.45m width is presented. Also the finite element method is utilized for solving the differential equations. Modeling of the turbulent flow around a single spur dike is performed using k-model in 𝜺 ANSYS software and the results were compared to those of the experimental study. The results show that the finite element method, by incorporating the k-model, models the flow pattern around the spur dike well and yields an average error value 𝜺 of 12.57%, and this shows a good agreement between the numerical modeling results and those of the experimental study.