開口式防砂壩下游沖刷坑防護策略探討

Downstream Scour Pits to Protect Open Check Dams

詹勳全(Hsun-Chuan Chan) ； 陳均美(Chun-Mei Chen) ； 謝孟荃(Meng-Chyung Shieh) ； 張建輝(Chien-Hui Chang)

《中華水土保持學報》 53卷4期 (2022/12) Pp. 221-230

https://doi.org/10.29417/JCSWC.202212_53(4).0001

摘要

本研究藉由水槽試驗，針對水保手冊及野溪現場常見之保護工進行水工試驗，探討不同設計型式的保護工於開口壩下游之消能情形，並針對開口壩下游保護工設計準則提出修正建議。依據試驗結果建議剛性保護工（靜水池及傳統護坦）佈設長度係數C值可採2.5、柔性保護工中主副壩間距係數（副壩及鼎塊工法）及佈設長度係數C值（拋石護坦）為3，可避免保護工基礎淘空之問題。而試驗過程中保護工消能情形則以拋石護坦效果最好，其次分別為鼎塊工法、副壩、靜水池及傳統護坦，沖刷深度削減率依序為90%、82%、70%、64%及62%，顯示依上述保護工配置建議，可抵抗開口壩射流及跌水衝擊，達到消能之目的。

關鍵字

開口壩 ； 局部沖刷 ； 防護策略 ； 保護工

並列摘要

In this study, we conducted hydraulic tests to evaluate the energy dissipation capabilities of different types of protective structures in areas downstream of open check dams. Our findings were used as the basis to formulate modified guidelines for such structures, which are as follows: To prevent scour at the foundations of protective structures, a coefficient of 2.5 can be applied for the length of rigid protective structures and a coefficient of 3 can be applied for the distance between primary and secondary dams and for the length of soft protective structures. The results of the hydraulic tests revealed that stone aprons provided the greatest energy dissipation effect, followed by hexa-hollow tri-leg structures, secondary dams, stilling basins, and concrete aprons, with scour depth reduction rates of 90%, 82%, 70%, 64%, and 62%, respectively. Moreover, these protective structures could all be used to reduce the kinetic energy of water flow.

並列關鍵字

Local scour ； open check dam ； protection strategy ； protective structure

參考文獻

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