Experimental study on wave-induced seabed response and force on the pipeline shallowly buried in a submerged sandy slope

Abstract

Waves on the submerged sloping seabed tend to transform and even break, inducing seabed response and exerting force on the shallowly-buried pipeline. In this study, a series of flume tests were carried out to characterize the wave propagation on a submerged sloping sandy seabed. Subsequently, seabed response considering the pipeline burial effect and ensuing force on the pipeline were investigated. Experimental results indicate that wave varies drastically on the sloping sandy seabed, accompanied with the nonlinearity strengthened. High-order nonlinear seabed response, at least the second order here, cannot be ignored. Pipeline presence, forming a smooth, impermeable and fixed circular boundary, makes the seabed response different from that without pipeline. The significance of the local hydrodynamics is highlighted after a heuristic investigation on the effect of pipeline relative water depth. For the pipeline buried in the shallow water, wave-induced horizontal force may be as important as the vertical force and should be taken into account in engineering. The relative burial depth and wave steepness at the toe are also found to affect the results obviously.