Experimental Study on Overtopping Failure of Landslide Dams
|關鍵字:||堰塞湖;溢頂潰壩;沖刷能力;水位變化速率;landslide dam;overtopping;erosive capacity;stage change rate|
利用實驗數據獲得之迴歸式歸納(在壩體下游坡角α = 35.5∘時)，當壩體縱剖面類型為平坦型或稱矮長壩(寬高比，B/H ≥ 7.20)時，其入流總水體積與壩體體積之比值將大於1800；而當壩體縱剖面類型為高聳型或稱高長壩(7.20 > B/H ≥ 1.20)時，其比值將介於240 ~ 1800之間。|
This study focuses on flume experiment to demonstrate the overtopping failure of landslide dam, and the purpose of this experiment is to observe and record the failure process. In the experiment, dam crest receives uniform erosion without encountering breach, so it can be considered as full-section erosion, i.e., one-dimensional mobile-bed process. Using the images captured by digital video camera, we discuss stage hydrograph, stage changing rate, dam profile with time, erosive capacity, and so on. Besides, using the functional relationship between dimensionless variables, we can obtain regression equation then compare it with field cases in Japan. Experimental results show that, during the overtopping failure, reflected wave and retreated wave occur respectively. We can discern them by the highest stage change rate and the second. There is a corresponding relation between erosive capacity and stage change rate. Major erosion happens between the highest stage change rate and the second. Taking the regression equation which is obtained from experiment data, under the condition of that slope of downstream face is degree of 35.5, it can be concluded that when the dam profile is flat (B/H ≥ 7.20), the ratio value of total inflow water volume to dam volume would be larger than 1800; when the dam profile is sharp (7.20 > B/H ≥ 1.20), the ratio value would be between 240 and 1800.
|Appears in Collections:||Thesis|
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