3D Finite Element Modeling of Suction Caissons Used as Foundations for Offshore Wind Turbines in Clayey Soils

Abstract

In this study, three-dimensional finite element modeling is utilized to simulate suction caisson foundations used for offshore wind turbines. The behavior of suction caissons in normally consolidated clayey soil subjected to lateral loading is investigated. A numerical model is calibrated and validated using experimental laboratory physical model. A parametric study is conducted to evaluate the effect of suction caisson diameter (D) and the ratio of skirt length (L) to caisson diameter (L/D) on the load-deflection response of a full-scale suction caisson. Several caisson diameters and length to diameter ratios were considered. The results of numerical analysis modeling demonstrated that the caisson ultimate load capacity and displacement are significantly affected by caisson geometry. Generally, increasing both the caisson diameter and length has substantially increased both caisson’s ultimate load capacity and displacement at failure. However, the increase in ultimate capacity and displacement reaches a threshold after which the increase in these values is less pronounced as D and L/D are further increased. Additionally, the effect of caisson geometry on relative stiffness is investigated. The relative stiffness of the suction caisson was found to increase proportionally with the increase of both diameter and length of the modeled caissons.