Three-dimensional interaction between anchor chain and seabed

Following the suction anchor installation, preloading of the anchor chain has to be carried out to remove slack. The assessment of a pretension level should take into account not only the additional chain slippage that may occur in service, but also the chain tension at the pad-eye which is transferred from the touchdown point (TDP) at the seabed. In this paper, a novel quasi-static model, which has considered the three-dimensional (3D) characteristics of soil resistance and chain elastic elongation, is presented to provide an accurate prediction of the behavior of an embedded chain. Based on this model, the chain profiles and tension distributions under different pretension levels are first calculated. While experiencing larger environment loads in service, the embedded chain will produce further movement in 3D space, which can be obtained by taking the chain equilibrium after pretensioning as the initial condition. Finally, the influence of pretension loads and angles at the TDP on the behaviors of embedded chain are thoroughly studied, and some useful conclusions are drawn.