Predicting the cyclic behaviour of suction caisson foundations using the finite element method

The deformation of suction caisson foundations in response to complex cyclic loadings is an essential consideration in their design. Under cyclic loadings, pore pressure and unrecoverable deformation in the foundations accumulate depending on the properties of both the foundation soil and the loads. In this paper, a finite element method (FEM) is developed based on a thermodynamics-based constitutive model. This paper first presents the formulation and calibration of the model. Then, the FEM numerical model is introduced. Finally, predictions are made for field trials of suction caissons in clay subjected to quasi-static cyclic loadings. The rotation angle and the settlement of suction caissons are well predicted. The pore pressure development and stiffness degradation in the foundation are also captured by the model. Furthermore, the effect of the ratio of skirt length to the diameter on the rotation of suction caisson foundations subjected to cyclic loads is studied numerically.