非水平式跌流工下游渠床沖刷行為之敏感度分析

Sensitivity Analysis of Scour Behavior for Non- Horizontal Drop Structure Downstream Channel Bed

宋狄晉(Ti-Chin Sung) ； 陳正炎(Jen-Yan Chen)

《水保技術》 9卷1期 (2014/01) Pp. 23-30

摘要

為河川整治或取水等目的，經常設置跌流工於河道中，雖可穩定上游河道，卻因砂石無法向下游運移，而淤積於跌流工上游河道，導致跌流工上游渠床坡度變大；依據台灣965座的防砂壩資料統計，其上游淤砂坡度小於0.06，共796座占82%，當上游渠床坡度改變時，亦加速水流沖擊力，是導致下游跌流保護工最易受損之原因。因此，本研究採定量清水流配合不同上游渠床坡度、單寬流量及不同跌流高度，組成自由跌流作用於不同渠床粒徑之渠槽試驗，經試驗結果提出具體有學理依據之沖刷特性參數之經驗模式，並進一步以比較探討各沖刷特徵參數之敏感度分析，期能為跌流保護工設計應用上之參考有所助益。

關鍵字

跌流工 ； 渠床粒徑 ； 敏感度分析

並列摘要

In recent years, hydraulic structures are commonly used in both natural and artificial channels of water resource management. Although the upstream channels can be stabilized, the gravel deposition in the hydraulic structures can increase the slope of the upstream channel bed. Based in Taiwan 965 of dams statistics, its upstream silt slope is less than 0.06, a total of 796 (82%), consequently lead to a sudden vertical change of the channel slope and induce a free overfall flow. As a result, the large impact forces of a free-falling nape from the free overfall flow also weaken the hydraulic structures. The scouring phenomenon of free overfall, constructed by a series of different drop heights; upstream channel bed slops and unit width discharges, acting on different graded-channel bottoms channel experiment. The experiment results have raised specific theoretical basis of the experience of scour hole pattern characteristic parameters. And further sensitivity analysis comparative study scour hole characteristics effects degree and The approach suggestion can be applied to design of protection works for hydraulic structures.

並列關鍵字

Drop Structure ； Bed Particle Size ； Sensitivity Analysis