上下游渠床坡度對自由跌流衝擊力與沖擊位置影響之探討

Study of Impact Force and Impact Position of Channel Bed Slope in Free Overfall

謝俊賢(Chun-Hsien Hsieh) ； 陳正炎(Jen-Yan Chen) ； 林漢昌(Han-Chang Lin)

《中華防災學刊》 5卷2期 (2013/08) Pp. 181-188

摘要

為達成河川整治或取水等目標，經常於河道中設置跌流工，雖可穩定跌流工上游河道，卻導致上游河道坡度增大。通過跌流工之自由跌流所產生之沖擊現象，通常是造成水工結構物損壞之主要原因，因此相關跌流水力參數與上下游渠床坡度之關係為何，實值得加以探討。本研究係理論推導改變跌流工上下游坡度後之沖擊力與沖擊位置之理論式，並運用坡度效應比δ，以及坡度影響值η探討上下游渠床坡度對沖擊力與沖擊位置自由跌流水力參數之影響。

關鍵字

衝擊力 ； 沖擊位置 ； 坡度效應

並列摘要

The hydraulic structures crossing the river have been widely used in both natural and artificial channels to process the water resource management. The hydraulic structures make upstream channel stable but increased channel slope in the same time. These structures usually induce the free overfall flow phenomenon, and a large impact force of free-falling nape due to free overfall flow usually damages the hydraulic structure. Therefore it is worth studying their relationships between impact force, impact position and channel slope. This study use slope effect ratio δ and slope influence value η to analyze the hydraulic parameters significance of upstream and downstream channel bed slope.

並列關鍵字

Impact Force ； Impact Position ； Slope effect