Physical Model of wave-induced seabed response around trenched pipeline in sandy seabed

Abstract

The phenomenon of wave-seabed-pipeline interactions is one of the primary concerns of coastal engineers and researchers, as it could greatly affect the seabed instability and pipeline safety. Numerous researchers have expended great effort in studying wave-seabed-pipeline interactions in the past. However, the majority of them focussed on the wave-induced response around a submarine pipeline, in buried conditions, by numerical models and laboratory experiments. Unlike the previous studies, a series of regular wave experiments and numerical model analyses were conducted to investigate the wave-induced pore pressure in the sandy seabed, around a pipeline with different backfilled depths. The model pipeline with three diameters (D = 6 cm, 8 cm, and 10 cm) is buried in three sizes of sand, d50 = 0.15 mm, d50 = 0.3 mm, and d50 = 0.5 mm, with different backfilled depths. The results show that the pore pressure amplitude in the seabed is a minimum with a backfilled depth D, and a maximum with full backfill or a backfilled depth of zero. The pore-pressure amplitude increases as the backfill sand median diameter increases. The effects of the pipeline diameter on pore-water pressure are also analysed and discussed.