Elasto-plastic characteristics of clayey soils contaminated by gasoil using cyclic triaxial apparatus

Oil-contaminated lands are one of the main concerns in geoenvironmental engineering. Contamination influences the pysical and mechanical properties of the ground particularly in fine soils. Purgation of such lands is sometimes too costly and impossible. Instead, in case of low contamination, they may be applicable to many land uses in engineering parctices. In such cases, the engineering properties of polluted areas are of great importance and necessity. Among oil products, gasoil due to its wide ranges of utilizations has the main contribution in contaminating areas. In this paper, the effect of gasoil contamination on the elasto-plastic properties of fine clayey soils has been discussed. Specimens of pure and mixed kaolinite with fine sand are contaminated by different gasoil contents (up to 16%) and tested using cyclic triaxial apparatus. Several load cycles are applied to remolded samples and stress–strain curves are obtained. The elastic and plastic strains of the samples in different cycles are evaluated. Based on the results, while gasoil contamination decreases elastic properties of the clayey soils, it increases the plastic strains. Thus, these areas fail more quickly particularly when are subjected to numerous load cycles as is the case in many repeated loadings.