عنوان مقاله [English]
Petrochemicals and transport fuel pollutants can change soil characteristics. The geomechanical and geotechnical behaviors of oil contaminated soil are therefore reviewed to ascertain their potential reuse as engineering material. Cook et al. (1992), Puri et al. (1994), Meegoda & Ratnaweera (1994) and Al-Sanad et al. (1995) reported the reduction in shear strength and stress-strain behaviors of clays, significant reduction in permeability, strength and compressibility of the contaminated soil, reduction in maximum dry density and optimum moisture content and increase in liquid and plastic limits of the soil. The reuse of contaminated soil as civil engineering materials is one of the effective alternative methods of disposing contaminated soil. However, this is subject to either the containment of the agent of contamination in soil or effective remediation of the contaminated soil. The pollutants can alter the consolidation characteristics of clayey soil, increasing the total or differential settlements of the foundations of engineering structures resting on it. This paper studies the effects of gasoline on geotechnical characteristics of commercial montmorillonite clay as, one of the most abundant clay minerals. The bentonite clay is artificially contaminated by gasoline. For this propose, bentonite clay is mixed with 4, 8, 12, and 16% of dry weight of soil by gasoline. Results show that with increasing gasoline, liquid limit increases 11% and the maximum dry density and optimum moisture content are decreased 1.5% and 40%, respectively. Unconfined compression strength and the cohesion of bentonite clay with increasing gasoline decrease more than 60%. The compressibility index with increasing gasoline up to 4 % increases, then it decreases between 4 % to 12 % of gasoline, and finally with increasing gasoline to 16 %, the compressibility index increases again. A linear model for evaluating compressibility index (Cc) of contaminated soil mainly composed of high plasticity clay is presented on the basis of liquid limit.