Session: 10-06-01 Pipelines and Cables

Paper Number: 126430

126430 - Laboratory Experimental Study on Local Scour Around Submarine Pipelines Caused by Seepage in Sandy Seabed 

In recent years, the significant demand for offshore oil and natural gas has made submarine pipelines widely used in various marine engineering scenarios. About 70% of oil and nearly 100% of natural gas require transportation through ocean pipelines. Submarine pipelines have become important tools and engineering structures for the transportation of underwater oil and natural gas. In practical engineering applications, the reliability and safety of submarine pipelines are important factors that must be considered.

The main reasons that affect the stability of submarine pipelines include scour and liquefaction damage. The former achieves the effect of reducing the local burial depth of the pipeline by taking away the soil around the pipeline; The latter achieves the effect of reducing the burial depth of the pipeline by losing the bearing capacity of the soil around the pipeline. Due to their different mechanisms, these two failure mechanisms have always been studied separately (Ke Sun, 2019; Liang and Jeng, 2020; Shaopeng Yang, 2019). However, in actual marine environments, erosion and liquefaction damage interact and act together. Therefore, combining the two to analyze the stability of submarine pipeline structures has great practical significance. 

In this experimental study, the influence of seabed response on sediment initiation and scour process is deeply comprehensively. The seepage force was obtained by measuring pore water pressure and analyzing it. The influence of seepage force on sediment initiation and equilibrium scour depth was analyzed under different wave heights and flow velocities. The experimental analysis shows that the effect of seepage force will suppress the development of sediment initiation at the peak of the wave, while promoting the development of sediment initiation at the valley of the wave. The influence of seepage force on sediment initiation increases with the increase of wave height and flow velocity, but decreases with the increase of water depth. The purpose of this study is to investigate the influence of seepage force on the scour process, and provide valuable experimental data and further insight into the investigation of the stability of pipelines.

 

Reference:

[1] Sun, K. ,  Zhang, J. ,  Gao, Y. ,  Jeng, D. S. ,  Guo, Y. , &  Liang, Z. . (2019). Laboratory experimental study of ocean waves propagating over a partially buried pipeline in a trench layer. Ocean Engineering, 173(FEB.1), 617-627.

[2] Liang, Z. ,  Jeng, D. S. , &  Liu, J. . (2020). Combined wave–current induced seabed liquefaction around buried pipelines: design of a trench layer. Ocean Engineering, 212, 107764.

[3] A, S. Y. ,  A, B. S. ,  B, Y. G. , &  C, L. Y. . (2019). Investigation on scour protection of submarine piggyback pipeline. Ocean Engineering, 182, 442-450.

Presenting Author: Yue Xu QINGDAO UNIVERSITY OF TECHNOLOGY

Presenting Author Biography: Graduated from Heilongjiang University with a bachelor's degree, currently pursuing a master's degree in marine geotechnical engineering at Qingdao University of Technology.

Authors:

Yue Xu QINGDAO UNIVERSITY OF TECHNOLOGY
Lin Cui Qingdao University of Technology
Dong-Sheng Jeng Qingdao University of Technology
Ke Sun ShanDong JiaoTong University
Bing Chen ShanDong JiaoTong University