Oil-contamination impact on bearing capacity of strip footing placed on geocell-reinforced sand under eccentric load

The infiltration of crude oil and its derivatives into the soil leads to changes in the mechanical behavior of the soil in addition to detrimental and environmental problems. This study aims to evaluate the bearing capacity of geocell-reinforced strip footings laid on oil-contaminated sand under eccentric load via numerical modeling using PLAXIS 2D. The behavior of the footing is assessed regarding various oil contents of 0, 3, 6, 9, and 12% under loading with different eccentricities of e/B=0, 1/12, 1/6, and 1/3. Numerical results revealed that soil pollution has a negative effect on the performance of strip footings, so that an increase in oil content led to a reduction in the magnitude of the load capacity. It was observed that reinforcement with geocell increases the bearing capacity of footing located on the oil-contaminated medium under different eccentricities. The effect of reinforcing with geocell was higher for contaminated soil compared to clean one. Further, the load capacity improvement factor (IF) increased by increasing oil content and settlement value. The results revealed that the reinforcing effect increased with an increase in load eccentricity for both clean and contaminated soils. In addition, the use of geocells is most effective when the loading is outside the core of the foundation, i.e., e/B>1/6. The footing tilting around the centerline axis of the footing due to load eccentricity as well as soil reinforcement with geocell led to a reduction in the stress-affected zone and as a result the displacement depth of the soil beneath the foundation.