Suction Piles and Suction Anchors for Offshore Structures-Article

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The paper reviews suction piles and embedded suction anchors (ESAs) as efficient, retrievable foundations for offshore structures. Suction piles penetrate the seabed under their own weight, then are driven deeper by reducing water pressure inside the pile. Installation pressure must remain within safe limits: too little will not overcome soil resistance, while excessive suction can destabilize soil inside the pile. Positive pressure can later assist retrieval.<br /><br />The authors outline design methods for horizontal, vertical, and inclined loading. Horizontal capacity is assessed using soil failure-wedge and equilibrium analyses. Vertical pull-out resistance depends on competing failure modes: the soil plug may lift with the pile, or the pile may slip through the soil. The lower capacity governs. ESAs are installed at the end of a suction pile, which is then removed, leaving the anchor buried. Their pull-out capacity is evaluated with adjustments for projected area and load eccentricity.<br /><br />Three applications demonstrate the systems’ versatility: concrete suction-pile foundations supporting a new breakwater; suction piles providing temporary moorings for immersed tunnel elements; and deeply embedded suction anchors securing a floating breakwater. In each project, the systems were installed and proof-tested successfully. The tunnel moorings also offered an alternative to seabed excavation, reducing environmental concerns.<br /><br />Overall, suction foundations combine relatively simple installation with substantial load capacity and retrievability. Their ability to penetrate soft seabeds and support large loads can make them an economical alternative to conventional piles and anchors, while reducing the need for extensive seabed disturbance.

Keywords

suction piles

embedded suction anchors

offshore foundations

retrievable anchors

seabed penetration

installation pressure

pull-out resistance

horizontal loading

temporary moorings

breakwater foundations