A Centrifuge and Analytical Study to Evaluate Suction Caissons for TLP Applications in the Gulf of Mexico

Abstract

This paper documents the results of a combined centrifuge and analytical study to evaluate the behavior of steel suction caissons under loading and soil conditions typical of deepwater Gulf of Mexico (GOM). Suction caissons are large cylindrical foundation units installed with active suction after partial penetration by deadweight. They derive most of their uplift resistance from passive suction. The results of this study help to verify the potentially large uplift resistances achievable with suction caissons. The centrifuge study confirmed that the dominant portion (60 to 70 %) of the uplift capacity is derived from the reverse end bearing or suction at the bottom of the caisson. This suction was maintained in the centrifuge tests for a sufficient period of time to resist all the foundation loads except the permanent pretension load. The caisson load-displacement behavior was also modeled using the finite element method of analysis, which exhibited excellent agreement with the results obtained from the centrifuge program.