Numerical investigation of seismic dynamic response and liquefaction characteristics of suction bucket foundation

Abstract

As offshore wind development expands into regions where earthquake induced seabed liquefaction may occur, the seismic performance of offshore wind turbine foundations requires careful assessment. In this paper, based on centrifugal test, the OpenSees finite element numerical models are established to investigate the dynamic response of bucket foundations with different aspect ratios (APs) under seismic loading. Based on the numerical results, the excess pore pressure ratio (EPPR) response, pore water pressure response, vertical seepage direction, and effective stress response of the bucket with an AP of 1.3 are analyzed. Furthermore, the superstructure response of the bucket foundation with different APs under seismic load is compared. Numerical analysis shows that the superstructure acceleration response increases with increasing AP. The study further examines the seismic liquefaction characteristics for different APs by analyzing the pore water pressure difference and the EPPR distribution. The characteristics of seismic liquefaction failure regions suitable for wide-shallow bucket and narrow-deep bucket are proposed. The results indicate that increasing AP reduces foundation settlement and the EPPR inside the bucket. This research aims to provide a reference for the seismic design of bucket foundations.