Safety analysis of rock berms that protect submarine power cables in the event of an anchor collision

A procedure for obtaining the dynamic characteristics of rock berms in the event of an anchor collision is developed, a safety analysis is performed, and associated recommendations are made. The drag coefficients of five target anchors were obtained through finite element flow analysis, and their terminal velocities calculated to maximise colliding kinetic energy. The dynamic behaviours of the rock berms were modelled by smoothed particle hydrodynamics (SPH). Six parameters were considered in the collision analysis: anchor type, collision velocity, SPH particle size, ground state, rock berm size, and collision point. The results were verified by an existing field test and a safety analysis was carried out with respect to parameter variation; the associated recommendations are discussed. It was found that rock berm height is the most critical factor in ensuring the safety of power cables. Rock size and installation depth are important to satisfy the safety criteria established in this study.