A case study of the application of wet top-feed vibro replacement stone columns as foundation supports for a fuel tank in a reclamation area

This paper presents a case study in which wet and top feed vibro replacement stone columns are used to support a 20-m-high fuel tank built on loose to medium sand deposits. The design considerations, installations, applications, field tests, correlations, and subsequent three-dimensional finite element analyses are presented. The soil profile of the case study comprised approximately 8 to 12 m thick loose to medium-dense silty sand layers with a high groundwater table. The 1-m-diameter stone columns were installed in a triangular pattern with a spacing of 2.1 m. The improvement depths were 8, 11, and 12 m. After construction was completed, quality assurance of the stone column installation was performed via various field tests. Based on the hydro test results, the improved ground could carry an allowable bearing capacity of 200 kPa transferred from the 20-m-high fuel tank and exhibited a maximum settlement of less than 50 mm, which met the design criteria of this project. Owing to reasonable quality control during stone column installation, the tilt of the tank caused by the nonuniformity of the improved sands was less than 10 mm. The enhanced strength ratio of the surrounding sands was 2 the densification effect. Furthermore, three-dimensional finite element simulations were performed. The results were consistent with the field measurements, verifying the effectiveness of the ground improvement technique. This case study demonstrates the practical application and benefits of vibro-replacement stone columns in enhancing bearing capacity, minimizing settlement, and improving overall foundation stability in challenging geotechnical environments, contributing to future engineering practices for similar projects.