Session: 06-11-01 Ocean Engineering Technology - I

Submission Number: 178341

Bed Shear Stress Amplification Around Rock-Berm Cable Protections 

Rock berm is one of the commonly adopted methods for enhancing the on-bottom stability of subsea cables and also for protecting cables from third-party damages, e.g., anchoring, fishing, falling and etc. Local scour will happen around the rock berm above an erodible seabed, especially at the corners of the rock berm, due to the amplification of the bed shear stress. If the local scour at the corners of the rock berm was not fairly considered during design and installation, scour holes may lead to cable spanning in the unburied neighboring sections which enlarges the damage risk.

In this work, the bed shear stress amplifications at the corners of the rock berm under various combinations of rock berm geometry, flow condition, sediment property have been investigated numerically. The accuracy of the numerical model is demonstrated with the data reported in literature.

The amplification factor is correlated with the governing parameters such as the height to width ratio of the rock berm, the slope of the corners, the Shields parameter over critical Shields parameter, normalized distance to the corners and etc. This amplification factor can be treated as the criterium of the onset of the local scour. Moreover, the dependence of the equilibrium scour depth on the amplification factor and the rock berm geometry is discussed. Finally, a predictive method for assessing the local scour around the rock berm is proposed and demonstrated with existing physical experiments.

Presenting Author: Yunfei Teng Dalian University of Technology

Presenting Author Biography: Dr. Teng is an Associate Professor and Doctoral Supervisor in Coastal and Oean Engineering. His research is dedicated to the dynamic submarine environment and structural safety, with specialized expertise in the on-bottom stability, free-span analysis, and scour protection of subsea pipelines and cables. His relevant work has been published in journals such as Coastal Engineering, Ocean Engineering and Physics of Fluids.

Authors:

Songsong Yu Central Southern China Electric Power Design Institute Co., Ltd. of China Power Engineering Consulting Group
Erxian Zeng Central Southern China Electric Power Design Institute Co., Ltd. of China Power Engineering Consulting Group
Yadong Wang Central Southern China Electric Power Design Institute Co., Ltd. of China Power Engineering Consulting Group
Heng Feng Central Southern China Electric Power Design Institute Co., Ltd. of China Power Engineering Consulting Group
Yuqi Dong Dalian University of Technology
Yuqian Yin Dalian University of Technology
Ruixiang Zhou Dalian University of Technology
Xinao Li Dalian University of Technology
Yunfei Teng Dalian University of Technology
Guoqiang Tang Dalian University of Technology