EFFECTS OF CRUDE OIL CONTAMINATION ON ATTERBERG LIMITS OF SELECTED SOIL ON THE SOUTH WEST KIRKUK-NE IRAQ

Abstract

The aim of this study is search the effects of adding crude oil on the atterberg limits of fine grain soil samples selected on the south west Kirkuk –NE Iraq. Due to the lack of information about this crucial topic in Iraq and in particular in Kirkuk city which is one of the richest oil cities in the world, this topic has been selected. The engineering properties of the study samples included (water content, grain size distribution, specific gravity and Atterberg limits). According to USCS the sample is (ML). The study sample was divided into two parts. The first part is uncontaminated soil (0%) which carried out for Atterberg limits tests, the second part is sub-divided into (four portions) crude oil was added to the four portions as (2%, 4%, 6%, 8%) after placing the contaminated samples in sealed containers for a period of two weeks (to gain sufficient homogeneity) then the Atterberg limits tests were carried out for those contaminated samples. The results indicated that increasing the percentage of crude oil from (0% to 4%) due to an increase in the Atterberg limits, and this may be attributed to the fact that the increase in the addition of crude oil to fine soil may lead to a distortion of the internal structure of clay minerals, after an increase in the percentage of crude oil (6% and 8%), a decrease in the values of (Atterberg limits) occurred as the doubled increase in crude oil leads to the replacement of a layer of non-polarized crude oil for liquids instead of a layer of water that surrounds the clay granules, which constrains the access of water to the fine particles.