Dynamic stability of oil tank supported by piled-raft foundation on liquefiable sand

Dynamic centrifuge model tests were performed to investigate a distinction between the mechanical behavior of an oil tank supported by a piled-raft foundation and slab foundation on liquefiable sand. Piles used for the former foundation are relatively short and embedded in the loose sand, and the vertical load supported by the raft, (RLP: Raft Load Proportion) was about 50% before shaking. Beneath the foundation, excess pore water pressures generated by the shaking are higher for the raft foundation than the slab foundation especially at depths near the pile tips. The higher excess pore water pressure causes the decrease of pile bearing load, resulting in the increase of RLP. Although the settlement of the piled raft foundation was larger than that of the slab foundation due to the increase of raft load, the uneven settlement was smaller for the piled raft foundation than the slab foundation.