Numerical Analysis of Pullout Capacity of Composite Suction Caisson Foundation Used For Large Scale Underwater Compressed Gas Energy Storage

Abstract The suction caisson foundation, characterized by its unique installation methodology and excellent bearing capabilities, has emerged as a crucial supporting structure for marine constructions. However, the distinctive alternating cyclic high load patterns exhibited by underwater compressed gas energy storage systems significantly challenge the vertical pullout bearing capacity of regular suction caisson foundations. In this study, a novel composite suction caisson foundation is proposed to enhance the vertical pullout capacity. The pullout capacity under perfectly drained conditions is investigated by finite element analysis with ABAQUS/Standard 2020. A comparative analysis of the pullout capacity between regular suction caisson (RSC) and composite suction caisson (CSC) is conducted, focusing on aspect ratios of 0.5, 1, and 1.5. The results show that the pullout load of the proposed CSC, with the same aspect ratio, increased by a range of 12.8% to 100% compared to that of the RSC. As the aspect ratio increases, the trend of increasing pullout load decreases. The variation of displacement for the caisson at its ultimate pullout capability is relatively small, between 0.01D and 0.027D.