Penetration resistance of tetrapod bucket foundations in clay considering soil large deformation and strength remoulding

Tetrapod bucket foundations represent a type of shallow foundation engineered to provide exceptional bearing performance for offshore wind turbines. While numerous studies have explored the bearing capacities of bucket foundations, the research remains sparse regarding the effect of installation and the corresponding soil flow patterns. This study simulates the installation of tetrapod bucket foundations using large deformation finite element analyses that account for soil strength remoulding. During the penetration of tetrapod bucket foundations, soil flows both into and out of the foundation, leading to observable soil heave. Although soil heave within each individual bucket is similar to that of a single bucket foundation, the heave occurring between the four buckets is influenced by their separation distance. The penetration resistance of the tetrapod bucket foundation is composed of inner side wall resistance, outer side wall resistance and end bearing capacity. The inner side wall resistance and end bearing capacity are relatively unaffected by the separation distance, whereas the outer side wall resistance exhibits a certain degree of sensitivity to this parameter. Finally, an expression for the penetration resistance of tetrapod bucket foundation is summarized, considering soil large deformation and strength remoulding.