Numerical analysis of suction caisson foundations under cyclic lateral loading in sand

Abstract

A parametric study on the monotonic and long-term cyclic response of suction caisson foundations for offshore wind turbines is presented. Three-dimensional finite element analyses of a caisson embedded in sand were performed in Abaqus/Standard using a semi-explicit calculation strategy. The monotonic and early cyclic response was simulated with a hypoplastic model with intergranular strain, while the long-term accumulation of permanent deformations was evaluated with the High-Cycle Accumulation model. The numerical results are analysed with respect to caisson rotation, accumulated tilt and effective stress changes in the surrounding soil. A parametric study was performed varying load eccentricity, vertical load, caisson aspect ratio, cyclic loading amplitude, loading symmetry and initial soil density. Finally, simplified relationships were calibrated from the finite element results to support preliminary serviceability-oriented design of suction caisson foundations under cyclic lateral loading.