Failure Envelopes and Optimal Loading Points of Suction Caissons in Layered Soil Profiles

This paper presents three-dimensional finite-element analyses to investigate the optimal loading point locations for suction caissons embedded in layered soil profiles. The soil profile consists of two clay layers with varying depths. The horizontal and vertical failure envelopes for different layered soil profiles are analyzed, and the calculated optimal loading point locations are presented in tables and graphs. These locations are examined in relation to the relative thickness of the upper soil layer and the strength ratio between the layers. Additionally, simplified models are proposed to predict the optimal loading point for both stiff-over-soft and soft-over-stiff clay scenarios. The findings reveal that the relative thickness of the upper soil layer and the strength ratio between the layers significantly influence the optimal loading point’s location. The depth of the optimal loading point ranges from 0.37 to 0.77 times the skirt length, depending on the soil parameters considered. These results offer valuable insights into the behavior of suction caissons in layered soil systems and provide practical guidance for the design and application.