Electrical Response of Selected High Hydrocarbons Contaminated Soils at ThiQar/Iraq

Abstract

– Electrical response of soil has many advantages and is increasingly utilized recently in identifying the
degree of contamination for sites associated with oil explorations and industry. In this paper, the electrical resistivity
method has been utilized to assess the electrical properties of two sites located at Thi-Qar Province southern Iraq.
Samples are collected from locations characterized by high hydrocarbon contamination by crude oil. A circular
resistivity cell of four equally spaced electrodes is self-constructed in the laboratory to test the naturally polluted
samples. For each sample, measurements are individually taking by injecting electrical current through a tested sample
in four vary sequences and determining the corresponding four readings of variation in the potential. Dipole-dipole
electrodes configuration is followed in gaining measurements. The impact of alteration the water content and soil
densification on the electrical response are considered for duplicating the possible disparities of structural and
hydrological conditions in the field. In addition to the geotechnical data, the outcomes of this study give the real ranges
of the electrical resistivity values of both locations that can offer a beneficial guide for geotechnical engineers for
assessing the suitability for construction and geotechnical performance of such highly polluted soils. Furthermore,
results show that the electrical characteristic is more governed by soil type and nature rather than the degree of
contamination. Also, results indicate a noticeable reduction in resistivity of polluted soil upon adding more water to the
sample until the soil reaches a higher degree of saturation at which no significant reduction in resistivity will occur. In
comparison to the lower void ratio samples, the higher void ratio samples that possess the same low water content
indicate higher resistivity in opposite to those possess the same high water content which indicates lesser resistivity and
vice versa.