Behaviour of laterally loaded pile groups embedded in oil-contaminated sand

Soil contamination with oil is not only harmful for the environment, but is also detrimental to associated buildings and foundations. Thus, the main aim of this study is to discover the influence of oil-contaminated sand on the lateral behaviour of pile groups. Single pile tests were also performed for comparison purposes. Small-scale model tests and a numerical study using finite-element analysis were performed on single piles and pile groups. The investigations were carried out by varying the percentage of oil content, the thickness of the contaminated layer and the pile group configurations. To fit the field conditions, contaminated sand layers were prepared by mixing the sand with oil content of 0–6% with regard to dry soil. The results indicated that the friction angle was reduced with increasing oil content. Thus, there is a significant decrease in the lateral resistance of the pile groups caused by oil contamination. The lateral resistance is decreased and the lateral deflection of the piles is increased with an increase in the thickness of the contaminated sand layer and percentage of oil content. For the middle pile in the lead row in the group, the maximum bending moment increased by about 40% at an oil content of 2% over that in clean sand. The agreement between observed and computed results is found to be reasonably good in terms of lateral resistance capacity and group efficiency.