BEHAVIOUR OF SKIRT FOUNDATION ON LOOSE SEA SAND WITH PULLOUT LOADING UNDER DRY AND SUBMERGED CONDITIONS

Skirt foundations are a type of foundation used for offshore structures such as oil and gas platforms and offshore wind turbines. The foundation is implemented for its high stability, ease of installation and economical. In the marine environment, the foundation has to resist tensile or pullout forces caused due to traction forces acting on the structure. This paper is focused on the study of the resistance offered by the skirt foundation to pullout forces. The test was done on model skirt foundation which was scaled down from the actual prototype. The pullout load was applied to the skirt foundation of different length of the skirt to its diameter (L/D) ratios of 0.5, 1.0, 1.5, 2.0 and 2.5 on loose sea sand under dry and submerged conditions. 10 laboratory tests were done on the model skirt foundations and their responses were studied. The increase in the L/D ratio increases the ultimate pullout load and the pullout resistance decreases on submergence.