Fig. 1. Protection matt over the scour pit.

그물형 세굴방지 매트를 사용한 수직말뚝의 유동에 대한 수치적 연구

Minxi Zhanga,b, Hanyan Zhaoc, Dongliang Zhao d, Shaolin Yuee, Huan Zhoue,Xudong Zhaoa
, Carlo Gualtierif, Guoliang Yua,b,∗
a SKLOE, School of Naval Architecture, Ocean & Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
b KLMIES, MOE, School of Naval Architecture, Ocean & Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
c Guangdong Research Institute of Water Resources and Hydropower, Guangzhou 510610, China
d CCCC Second Harbor Engineering Co., Ltd., Wuhan 430040, China
e CCCC Road & Bridge Special Engineering Co., Ltd, Wuhan 430071, China
f Department of Structures for Engineering and Architecture, University of Naples Federico II, Italy

Abstract

Local scour at a pile or pier in current or wave environments threats the safety of the upper structure all over the world. The application of a net-like matt as a scour protection cover at the pile or pier was proposed. The matt weakens and diffuses the flow in the local scour pit and thus reduces local scour while enhances sediment deposition. Numerical simulations were carried out to investigate the flow at the pile covered by the matt. The simulation results were used to optimize the thickness dt (2.6d95 ∼ 17.9d95) and opening size dn (7.7d95 ∼ 28.2d95) of the matt. It was found that the matt significantly reduced the local velocity and dissipated the vortex at the pile, substantially reduced the extent of local scour. The smaller the opening size of the matt, the more effective was the flow diffusion at the bed, and smaller bed shear stress was observed at the pile. For the flow conditions considered in this study, a matt with a relative thickness of T = 7.7 and relative opening size of S = 7.7 could be effective in scour protection.

조류 또는 파도 환경에서 파일이나 부두의 국지적인 세굴은 전 세계적으로 상부 구조물의 안전을 위협합니다. 파일이나 교각의 세굴 방지 덮개로 그물 모양의 매트를 적용하는 것이 제안되었습니다.

매트는 국부 세굴 구덩이의 흐름을 약화시키고 확산시켜 국부 세굴을 감소시키는 동시에 퇴적물 퇴적을 향상시킵니다. 매트로 덮인 파일의 흐름을 조사하기 위해 수치 시뮬레이션이 수행되었습니다.

시뮬레이션 결과는 매트의 두께 dt(2.6d95 ∼ 17.9d95)와 개구부 크기 dn(7.7d95 ∼ 28.2d95)을 최적화하는 데 사용되었습니다. 매트는 국부 속도를 크게 감소시키고 말뚝의 와류를 소멸시켜 국부 세굴 정도를 크게 감소시키는 것으로 나타났습니다.

매트의 개구부 크기가 작을수록 층에서의 흐름 확산이 더 효과적이었으며 파일에서 더 작은 층 전단 응력이 관찰되었습니다.

본 연구에서 고려한 유동 조건의 경우 상대 두께 T = 7.7, 상대 개구부 크기 S = 7.7을 갖는 매트가 세굴 방지에 효과적일 수 있습니다.

Keywords

Numerical simulation, Pile foundation, Local scour, Protective measure, Net-like matt

Fig. 1. Protection matt over the scour pit.
Fig. 1. Protection matt over the scour pit.
Fig. 2. Local scour pit of pile below the protection matt.
Fig. 2. Local scour pit of pile below the protection matt.

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