A Numerical Analysis on Lateral Resistance of Pile-Bucket Foundation for Offshore Wind Turbines

The large-diameter single pile has been widely used in marine wind turbine foundations. In order to improve its lateral bearing capacity, the suction bucket foundation (BF) can be used as a reinforcement method, which surrounds the periphery of the monopile foundation (PF), forming a new wind turbine foundation, i.e., pile-bucket foundation (P-BF). By using the general finite element software ABAQUS, in this paper, several numerical models are established to investigate the influence of pile diameter and bucket diameter on the lateral bearing capacity of large-diameter monopiles. The numerical results show that the internal force distribution along the pile shaft for the case of P-BF is similar to the case of PF. Compared to bucket height, bucket diameter has more of an effect on lateral capacity and the p-y curve in the P-BF. In the combined P-BF, the buckets can provide lateral bearing capacity, and the piles can provide anti-overturning moments, resulting in higher lateral bearing capacity. In this paper, the p-y curve in the API specification is modified based on the results from the finite element simulation. The modified p-y curve fits well with the results of the finite element calculation and can be used as a reference for the design of the P-BF in actual engineering.