Laboratory experimental study of ocean waves propagating over a partially buried pipeline in a trench layer. (1st February 2019)

• Record Type: Journal Article
• Authors: Sun, Ke; Zhang, Jisheng; Gao, Yuan; Jeng, Dong-sheng; Guo, Yakun; Liang, Zuodong
• Is Part Of: Ocean engineering. Volume 173(2019)
• Page Start: 617
• Page End: 627
• Publication Date: 2019-02-01
• Subjects: Wave-seabed-pipeline interaction -- Soil response -- Trenched pipeline -- Partially buried; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2019.01.022
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: Seabed instability around a pipeline is one of the primary concerns in offshore pipeline projects. To date, most studies focus on investigating the wave/current-induced response within a porous seabed around either a fully buried pipeline or a thoroughly exposed one. In this study, unlike previous investigations, a series of comprehensive laboratory experiments are carried out in a wave flume to investigate the wave-induced pore pressures around a partially embedded pipeline in a trench layer. Measurements show that the presence of the partially buried pipeline can significantly affect the excess pore pressure in a partially backfilled trench layer, which deviates considerably from that predicted by the theoretical approach. The morphology of the trench layer accompanied with the backfill sediments, especially the deeper trench and thicker backfill (i.e., b ≥ 1 D, e ≥ 0.5 D ), provides a certain degree of resistance to seabed instability. The amplitude of excess pore pressure around the trench layer roughly exhibits a left-right asymmetric distribution along the periphery of the pipeline, and decays sharply from the upper layer of the trench to the lower region. Deeper trench depth and thicker buried layer significantly weaken the pore-water pressures in the whole trench area, thus sheltering and protecting the submarine pipeline against the transient seabed liquefaction. Highlights: First comprehensive experimental data for wave-induced pore pressure around buried pipeline in a trench layer. Investigate effect of wave characteristics on transient pore-water response near the partial-buried pipeline. Examine effect of trench depth and backfill thickness on oscillatory pore-water pressure around the partial-buried pipeline.