Investigation of the Impact of Considerable Oil Contamination on Mechanical Properties of Fine-Grained Soils

The regional waterways, especially Persian Gulf and Oman Sea, are witnessing the passage of giant oil tankers daily. Due to oil extraction in the oil fields, wars in the region, unexpected incidents, and various explosions, southern areas of Iran are contaminated with oil derivatives. In this paper, the impact of crude oil and gas oil contamination on clayey fine soil and its impact on coastal structures is investigated. For this purpose, in addition to preliminary tests, hydrometer test, direct shear test, unconfined compressive strength and solidification were carried out on contaminated soils. It was found that the presence of more than 20% of petroleum derivatives on clayey soil leads to a sharp decrease in soil shear strength, which is considered as a serious risk for the coastal structures and oil field structures. Also, by using type II cement with 10% of dry soil weight, in addition to the relative increase in soil strength, it can also prevent the movement of contamination in water and soil substrates.