Abstract:China"s offshore waters are located in the Pacific Rim seismic zone, and the large-diameter group pile foundations commonly used in marine engineering are facing seismic threat.In this paper, the dynamic response characteristics of offshore large-diameter group pile foundations are investigated using 1g shaking table model tests, and the effects of large-diameter group pile foundation arrangement and different seismic inputs are investigated.The results show that, under the same conditions, the Taft seismic wave is more likely to cause liquefaction of the soil around the piles more cyclic cycles number and lower principal frequency compared with the El-Centro seismic wave; the principal frequency of the El-Centro seismic wave is closer to the intrinsic frequency of the modelled foundation, which leads to the more significant peaks in the base acceleration and bending moment responses. Under the same amount of consumables, the superporous pressure ratio response of the soil around the piles of the nine-pile arrangement is stronger than that of the four-pile arrangement; under all the loading conditions, the acceleration response of the four-pile foundation is stronger due to the fact that it is easier to liquefy in the shallow region, and the degree of liquefaction of the four-pile foundation is lower, whereas this pattern is opposite in the deeper region; the bending moment distribution of the nine-pile foundation is more uniform, and the seismic performance of the nine-pile foundation is stronger than that of the four-pile foundation. Overall, the overall seismic performance of nine-pile foundation is better.