This paper offers robust analytical equations and design configuration for finned piles based on the results of an extensive three-dimensional finite element analysis considering geotechnical and structural calculations. The expressions presented in this paper consider the influence that different aspect ratio of the caisson, fin configuration and soil characteristics, have on the finned pile response then enabling faster and optimised design process for developments in very soft deep-water clays.
Suction piles for deep-water developments present a staple foundation solution. Owing to their excellent holding capacity characteristics in the combined V-H space, suction piles are deployed for a variety of applications, including holdback or hold down anchors for in-line pipeline structures and risers, mitigations against pipeline walking, or indeed for pipeline initiation purposes. The load for the applications mentioned above is usually transferred to the piles through the top plate (top loaded). There are occasions where to maximise the efficiency of the suction piles, the load is transferred via a padeye located at the side of the skirt as typically adopted for mooring piles of Floating Production, Storage and Offloading (FPSO) vessels. Depending on the application, suction piles may experience large magnitude horizontal loads, either arising from environmental conditions, operational loading from hydrocarbon circulation or infrastructure installation.
Universities of Newcastle (UK) and Hamburg (Germany) started to investigate in the early 2000s how the addition of fins to the skirt can enhance the lateral response of suction piles, having the focus on windfarm foundations. Grabe and Duhrkop (2007) found a potential increase in lateral capacity from 10% to 60% as compared to a monopile where the optimal fin location was not at mudline. In addition, Durhkop and Grabe (2008) showed that any pile with fins has a stiffer system response as compared to a monopile, regardless of the shape and position of the wings. Subsequently, Peng et al., (2010) presented that for a monopile to provide the same resistance as a fin-enhanced pile, then the diameter of the monopile must exceed the core diameter of the finenhanced pile. Further salient findings can be found in Irvine et al., (2003), Grabe and Duhrkop (2007), Bienen et al., (2012) Duhrkop and Grabe (2009), Rudolph and Grabe (2013).
