Load bearing behaviors of composite bucket foundations for offshore wind turbines on layered soil under combined loading

This paper focuses on the load bearing behaviors of the composite bucket foundation (CBF) which has been proposed and applied to offshore wind turbines in China. With the numerical analysis method, the soil-structure interaction and the practical project-based dimensional and property parameters are described. The load bearing behaviors of the CBF are investigated in terms of deformations (structure and soil), load bearing ratios, and geometric effects. Under the consideration of multi soil profiles and combined loading condition, the load bearing behaviors of the CBF can be concluded. Soil property can change the load bearing ratio especially when the compartment plates are involved. The lid-bearing mode is dominant for CBF when the upper layer of the soil is high in strength. Without the compartment plates, the bucket wall contributes more than the lid. The load bearing behavior is influenced by the bucket diameter, soil strength and the compartment plates. The results are of reference value to understand the load bearing behaviors and serve as a basis for optimizing the structure design for cost-reduction.