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標題: A Study on the downstream bed scouring of the silt-type dam
關鍵字: 狹縫密度
the silt density
relative opening width
the ratio grain concentration by volume
出版社: 水土保持學系
摘要: 中 文 摘 要 在過去對梳子壩之研究主要在針對梳子壩狹縫密度、相對開口寬度(b/dmax)等對土石流之貯砂效率、泥砂體積濃度折減效率等影響,且沖刷坑之研究亦以傳統防砂壩及開口式滯洪壩為主,並無針對梳子壩下游沖刷坑之試驗研究,故本文利用渠槽試驗以三種流量、三種坡度及7種狹縫密度來探討梳子壩之下游沖刷坑之型態。 經試驗結果顯示,在相同狹縫密度下,渠槽坡度及流量增加時,沖刷坑各因子會隨之增加,但在相同渠槽坡度及流量下,沖刷坑各因子並不會因狹縫密度減少而增加,成不規則變化;梳子壩之狹縫密度愈大時,下游各沖刷坑彼此之間愈獨立且沖刷坑各因子最大值發生位置集中在渠槽之中間,但在狹縫密度愈小時,則反之,成一均長之條狀沖刷坑且沖刷坑各因子最大值發生位置並不固定。 關鍵字:狹縫密度、相對開口寬度、泥砂體積濃度折減效率
ABSTRACT In the past, researches of the silt-type dam apparently focused on the trop efficiency of the debris flow and the ratio grain concentration by volume, which are influenced by factors such as the silt density of the silt-type dam, and the relative opening width (b/d max). As to the studies of the scouring hole, they also concentrated in the traditional check dam and the flood detention dam. Researchers seldom pay attention to the downstream scouring hole of the silt-type dam. Under such circumstances, we use indoor flume experiment to discuss the types of the downstream scouring hole resulting from three different discharges, three different slopes of channel, and seven kinds of silt density in this study. As a result of the experiment, with the increase of the discharge and the slope of channel, the factors of the scouring hole consequently increase. However, with the same slope and the same discharge, the factors of the scouring hole don’t increase although the silt density decreases. The interrelationship between them shows irregular changes. Besides, the heavier the silt density of the silt-type dam, the more independent between each down-stream scouring hole, and the maximum of the factors of the scouring hole occurs mainly in the center of the channel. But as the silt density becomes smaller, the situations reverse. The scouring hole forms a uniformly narrow long strip type, and the location, which the maximum of the factors occurs, is not certain. Keywords:the silt density、relative opening width、the ratio grain concentration by volume
Appears in Collections:水土保持學系



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