Semnan University Press Journal of Rehabilitation in Civil Engineering 2345-4415 13 4 2025 11 01 Shear Strength Behavior of Oil-Contaminated Bushehr Carbonate Sand 177 189 9314 10.22075/jrce.2025.35520.2180 EN Masoud Fallah Department of Civil Engineering, Arak Branch, Islamic Azad University, Arak, Iran Ahmadreza Mazaheri Department of Civil Engineering, Faculty of Engineering, Ayatollah Borujerdi University, Borujerd, Iran Hamid Lajervardi Department of Civil Engineering, Arak Branch, Islamic Azad University, Arak, Iran Masoud Nasiri Department of Civil Engineering, Faculty of Engineering, Kermanshah University of Technology, Kermanshah, Iran Tisfun Artificial Intelligence Company, Kermanshah, Iran 0000-0003-2371-7517 Journal Article 2024 10 05 The crude oil leakage in soils could lead to an extreme reduction in resistance. It is significant for oil-rich countries, such as Iran, with several crude oil resources. The clean and oil-contaminated Bushehr carbonate coastal sand cyclic simple shear behavior is investigated. The clean and crude oil-contaminated sands were prepared with a relative density of 60%, and oil-contaminated samples were prepared using 2%, 4%, and 6% crude oil. Shear modulus (<em>G</em>) and damping ratio (<em>D</em>) rely on soil particle characteristics. Using 2% crude in Bushehr carbonate sand leads to an approximately 5% increase in shear modulus. Also, applying 4% oil in the specimens caused roughly 8% enhancement in the dynamic strength of Bushehr carbonate sand. Keeping the conditions constant, the effects of oil contamination on this carbonate sand were investigated using a cyclic simple shear apparatus. The results indicate that 6% crude oil contamination will lead to a decline in shear modulus (10.6%), a growth (27.6%) in the damping ratio, and a decrease (16.6%) in the friction angle of Bushehr sand in comparison to clean sands. However, 2% and 4% contamination led to static and dynamic resistance increase of Bushehr carbonate sand. The results indicated that using 2% and 4% crude oil caused a 12.5% and 20.8% increase in the static resilience of Bushehr carbonate sand, respectively. https://civiljournal.semnan.ac.ir/article_9314_9afe487de556e59e6db6c862adfe25a4.pdf