Abstract: Coral sand is widely used in island and reef reclamation projects, but its distinct physical and mechanical properties compared to land-based sand. To explore the deformation mechanism of hydraulic filled coral sand foundation, oedometer tests were conducted on coral sand, considering the combined effects of factors such as gradation, porosity, and loading methods. The initial particle size distribution of coral sand significantly impacts its compression deformation characteristics, with noticeable particle breakage. A larger initial void ratio in gravel sand results in greater compressibility. The deformation of coral sand primarily involves pore filling by particle movement, accompanied by minor particle breakage, all of which are irreversible plastic deformations. Consequently, the unloading index of coral sand is only 1/10 that of clay. Finally, a three-dimensional model of the aviation oil storage tank was created using Plaxis 3D software. Using mechanical parameters obtained from laboratory experiments, the deformation of the coral sand foundation in aviation oil storage tank engineering under cyclic loading and unloading was studied. The model’s accuracy was validated by comparing it with the monitoring results of the aviation fuel storage tank project at Maldives’ Ibrahim Nasir International Airport. At the maximum storage capacity of the aviation oil storage tank, the coral sand foundation reaches its peak deformation. At this load level, multiple loading and unloading cycles will not cause further deformation, providing valuable guidance for engineering safety control.

Key words: large storage tank, coral sand, nonuniform settlement, finite element simulation