Ensuring structural protection in the vicinity of crude oil (CO) resources is a crucial aspect in geo-environmental considerations. If CO spills into soils, a severe drop in strength occurs, leading to significant ecosystem and civil engineering problems. This topic is paramount for those nations with high CO resources, such as Iran. The presented paper discusses the execution of meticulous chemical examinations (i.e., FTIR, SEM, and XRF) and physical experiments using a simple shear device (SSD). The soil studied in this paper is Ottawa sand (OS), known for its silica nature. This research introduces a novel approach for treating artificially CO-contaminated silica sand. Therefore, this paper employed Bentonite Nanofluid (BNF), an environmentally friendly agent, for treating CO-contaminated OS specimens. The consequences reveal that this novel method in geotechnical engineering can broadly enhance CO-contaminated OS's static and dynamic strength of CO-contaminated OSs. The OS specimen's relative density in all physical analysis cases was 60% due to similarity to field conditions. Additionally, the CO content in contaminated OS specimens was 6 wt%. Four different natural bentonites (NB) were selected to fulfill the objective of this investigation, which is to obtain the optimum one (with the highest adsorption capacity) for the BNF preparation process. The optimal CO adsorption was achieved with 5 wt% BNF. The results exhibited that using a novel treatment agent (i.e., BNF) leads to >25% and 17% growth in dynamic and static strength of CO-polluted OS, which are notable values. Furthermore, preparing and using this technique is straightforward and practical.
