A Numerical Study on the Behavior of Offshore Suction Bucket Foundations under Cyclic Lateral Loading

Offshore wind turbines are exposed to high cyclic lateral loads induced by wind and waves which play a special role in the design of foundations. It's essential to clarify the bucket behavior under cyclic lateral loading to fulfil the design requirements of these foundations in both ultimate and serviceability limit states. In this study the behavior of monopods embedded in saturated sandy soil subjected to cyclic lateral loads were investigated using a sophisticated finite element model. The accumulation of permanent soil deformations and excess pore water pressure in saturated sandy soil due to cyclic lateral loading are taken into account by a fully coupled two-phase model combined with a hypoplastic constitutive model. Porosity-permeability dependence is modelled with the Kozeny-Carman relationship. The main focus was dedicated to loads levels that led to progressive failure, attenuation, and shakedown behavior under cyclic lateral loading. The main finding of these investigations are presented which make an effective contribution to the safe and economic design of bucket foundations.