On-Bottom Stability Analysis of Subsea Power Cable Resting on Rocky Seabed
摘要
The subsea power cable industry has been growing rapidly in offshore petroleum sectors. The present study has been limited to cable resting on the rocky seabed. Compared with deep water, achieving bottom stability in shallow water is challenging task when the cable is exposed to breaking waves and fast tidal currents. There are certain philosophical differences between the design methodology of subsea pipelines and cables. Due to deeper locations than the existing pipelines, subsea cables are more deeply into the boundary layer of seabed, resulting in wave loading often increasing relative to steady current loading. The smaller diameter of subsea cable also leads to a higher Keulegan–Carpenter number for the flow; combining all these, it’s difficult to achieve bottom stability, as well as spanning behavior is a bit challenging. Accurate estimation of lateral resistance is crucial to ensure the on-bottom stability of cables. Analysis using conventional cable on-bottom stability design procedure tends to overestimate lateral resistance behavior. Major objective of the cable dynamic bottom stability is to arrive the mitigation measures to make cable stability under hydrodynamic loads. The present study has established mitigating techniques for the subsea cables based on lateral displacement criterion. The extreme lateral displacement will damage umbilical and power cables and result in collisions between them.