請用此 Handle URI 來引用此文件: http://hdl.handle.net/11455/47307
標題: 變量流作用下之固床工沖刷試驗研究
Laboratory Experiments for Scour Downstream of a Grade-Control Structure under Unsteady Flow Conditions
作者: 盧昭堯
關鍵字: 土木水利工程類
基礎研究
摘要: 多階式固床工已被廣泛應用於河床穩定、橋基保護及灌溉取水。然而多數文獻僅著眼於定量流清水沖刷下之固床工下游側最大沖刷深度,變量流之研究則誠屬有限。本研究擬以高速攝影機建置具高時間解析之質點影像流速觀測技術,配合一般數位攝影機連續記錄沖刷坑之沖刷歷程,分別探討定量流及變量流作用下,固床工下游側沖刷坑剖面型態及最大沖刷深度之時變歷程。為深入研究沖刷坑之水沙交換機制,本研究採循序漸進之方式,第一年將針對單道固床工進行定量流作用下之沖刷歷程,測試及建構高速攝影機運用於沖刷坑內流場之觀測,並初步分析沖刷坑內泥沙捲增率、底床剪應力及猝發現象之關係;第二年則進行變量流試驗,結合第一年之研究成果,逐步修正變量流作用下之沖刷坑時間尺度,並初步完成變量流沖刷歷程模式之建構。最後,本研究於第三年,除持續進行變量流試驗外,將進行雙道固床工之沖刷觀測,並針對第二年之清水沖刷變量流沖刷歷程模式進行修正,使其可進一步用於第二道固床工之濁水沖刷情況。本研究完成後將有助於吾人對多階固床工(單、雙道)下游側沖刷機制之瞭解。此外,沖刷坑剖面之模擬及沖刷歷程之推估,均可提供相關沖刷防制應用之參考。
Grade-control structures (GCSs) have been widely used as tools for channelstabilization, bridge-pier scour countermeasure, and water withdrawal purposes.However, most investigators had focused on the variations of the maximum scourdepth downstream of a GCS under steady flows with clear-water conditions. Theunsteady flow conditions were seldom considered.The aim of the study is to use a digital high-speed camera (DHSC) corporatingthe particle image velocimetry (PIV) measuring technology to investigate the scouringprocesses in the scour hole downstream a GCS. This is a three-year study. For the firstyear, the DHSC will be tested and the measuring methodology will be developed, andthe sediment entrainment mechanism and the bursting process will be investigated.For the second year, the experiments with unsteady flow conditions will be conducted.The model for the temporal variations of scour depth under unsteady flow conditionswill also be established. Finally, during the last year, two consecutive GCSs will beinstalled in the flume and the live-bed scour conditions downstream of the secondGCS will be investigated.The proposed study is useful for clarifying the important scouring mechanismdownstream of a GCS for both the clear-water and live-bed conditions. In addition,the predictions of the scour-hole profile and the temporal variations of scour depthwill offer valuable information for scour prevention designs.
URI: http://hdl.handle.net/11455/47307
其他識別: NSC99-2221-E005-045-MY3
文章連結: http://grbsearch.stpi.narl.org.tw/GRB/result.jsp?id=2387732&plan_no=NSC99-2221-E005-045-MY3&plan_year=101&projkey=PB10101-2999&target=plan&highStr=*&check=0&pnchDesc=%E8%AE%8A%E9%87%8F%E6%B5%81%E4%BD%9C%E7%94%A8%E4%B8%8B%E4%B9%8B%E5%9B%BA%E5%BA%8A%E5%B7%A5%E6%B2%96%E5%88%B7%E8%A9%A6%E9%A9%97%E7%A0%94%E7%A9%B6
顯示於類別:土木工程學系所

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