Finite Element Analysis of Elastic Behavior of Suction Caisson

Abstract

As the demand on energy increases rapidly, exploration and production in deep water and facilities in shallow water are in imperative need. Suction caissons are most commonly used as anchoring system for offshore floating structures and are used as foundations for coastal wind turbines in relatively shallow water. For a long time, suction caisson loaded in soft clay such as in Gulf of Mexico are considered rigid due to the stiffness being stronger than soft clay.

The objective of this study is to investigate the elastic behavior of suction caissons in soft clay. A new 3-D finite element analysis method using coupled caisson-springs model is introduced. The properties of springs are developed based on a 2-D continuum finite element analysis and scaled to 3-D scenario. Computer program ABAQUS is used for the numerical analysis for the coupled caisson-springs model.

Results show that elastic behavior of caissons is quite different with a rigid caisson particularly under small displacement. Taking the advantage of the newly developed model, the structural response of the caisson is also assessed.