KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
권호 표지

Characteristics of Local Scour under the Pipelines on the Seabed in Waves

해저 바닥에 놓인 관로하의 파에 의한 국부세굴 특성

Oh, Hyoun-Sik;Kim, Kyoung-Ho;Park, Jae-Sung;Lee, Ho-Jin
오현식;김경호;박재성;이호진

  • Published : 2004.05.31

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Abstract

Submarine pipelines are very convenient means to transport oil, gas, water and waste water along the sea bed, so they are widely used in coastal structure. When a pipeline is placed on an erodible bed, scour will develop, causing failure of the pipeline. In order to confirm that pipelines are stable and functional for their projects period, we must give attention to their coastal process. The scour phase is one of the most important subjects when we set up the pipelines in submarine. This paper presents experimental investigations of scour depths with period(T), pipe diameter(D), local wave heights(H) for the horizontal bed and 1/10 sloping bed cases. Based on the obtained data for each live bed condition, This study suggested equilibrium scour depths with relation to KC number and modified Ursell number. In both cases of the horizontal and sloping bed, scour patterns which are different from general scour phases were observed. This phenomenon was explained by the embedment ratio(e/D), namely displacement of seabed's bottom levels by variation of distributed flow field around pipelines.

해저관로는 원유, 가스, 공업용수 및 폐수를 운반하기 위해 사용되는 편리한 수단이기 때문에 광범위하게 사용되는 해안구조물이다. 해저관로가 침식성 지반에 놓이면 세굴이 발생하고, 이는 해저관로 파괴의 원인이 되기도 한다. 해저관로가 설치기간 동안 안정적으로 제 기능을 다하기 위해서는 해저관로 주변의 해안과정에 대해 관심을 기울여야 한다. 특히 세굴현상은 해저관로 설치시 가장 주의해야 하는 사항이다. 본 논문에서는 수평과 1/10 경사를 가진 이동상에서 파의 주기, 관경, 국부파고를 변화시켜가며 실험을 실시하여 세굴심과 이러한 매개변수들 간의 관계를 조사하였다. 실험을 통해 얻어진 자료를 분석하여 평형세굴심과 KC 수 및 수정 Ursell 수와의 관계를 제시하였다. 두 가지 경우 모두 일반적인 세굴양상과 다른 이상세굴이 발생하였으며, 이는 흐름장의 변화에 의한 해저 하상의 변위 즉, 매설깊이와 관경의 비로 표현되는 상대 매설깊이(e/D)의 변화에 의해 설명할 수 있다.

Keywords

References

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