On the Behaviour of Suction Buckets under Cyclic Lateral Loads

safe and economic design of suction bucket foundations for offshore structures requires profound knowledge about soil bucket systems behaviour under cyclic loads. Cyclic loads induced by wind and waves can lead to an accumulation of permanent soil deformations and excess pore water pressures in water saturated soils. This has to be considered in ultimate limit state and serviceability design. In this paper the behaviour of soil-bucket-systems subjected to cyclic lateral loads is analyzed numerically. In the finite element analyses a fully coupled two-phase model combined with a hypoplastic constitutive model for the water saturated soil is used for realistic determination of interactions between the structure, the water-saturated soil and the pore water. The main focus of the numerical investigations is on the quantitative determination of the impacts of different cyclic loading types on accumulation effects. Calculations with cyclic one-way and two-way loads show that the accumulation of permanent deformation and pore water pressures in saturated soils and hence the interactive behaviour of soil-bucket system are significantly influenced by cyclic loading characteristics.