A theoretical study of wave-induced response of buried long submarine cables

Abstract

Subsea power cable, which is essential for offshore renewable energy, is often buried within the seabed in coastal areas to ensure safety. Nevertheless, waves can produce dynamic pore pressure within the seabed, and hence cause some dynamic response of the cable, which has been rarely studied. To close this gap, a simple analytical model is developed for obtaining harmonic oscillation of a deeply buried cable. An approximated solution for wave-induced force is derived based on the assumption of large embedding depth. The cable is treated as an infinitely long Euler–Bernoulli beam buried in a viscoelastic foundation. Harmonic solution of the cable’s deformation in the vertical and transverse direction is obtained for an arbitrary wave-cable angle. A parametric analysis is carried out for typical cables. It is found that there exists an optimal wave period that maximizes the cable’s response under a given water depth. Under breaking-wave conditions, the wave-induced cable deformation is still sub-millimetre, showing that seepage flow does not pose a big threat. Finally, the shape of deformed cable is found to be helix when the wave-cable angle is between 0 and $\pi /2$.