Abstract：To improve the bearing capacity of offshore wind turbine foundation, a pilebucket composite foundation with bucket foundation and steel piles was designed. Based on the limit equilibrium method, the theoretical formula of horizontal bearing capacity of pilebucket composite foundation was proposed with considering different pile numbers. The finite element analysis model was established to analyze the bearing capacity of pilebucket composite foundation with different pile numbers, pile diameters and arrangements. The results show that the ultimate bearing capacity of pilebucket composite foundation can be effectively improved for the same steel amounts of foundation. Compared with single bucket foundation, the bearing capacity of bucket foundation with 1 pile is increased by 44.27%, and the bearing capacity of bucket foundation with 3 piles is increased by 35.76%, while the bearing capacity of bucket foundation with 4 piles is increased by 34.73%. Obvious wedgeshaped equilibrium plastic strain is appeared in the soil foundation of the passive area. The more obvious the
equilibrium plastic strain is, the higher the load sharing ratio of foundation soil is, and the higher the bearing capacity of foundation is. The high stress area of foundation is mainly concentrated in the top cover of foundation.
