Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/34128
標題: An experiment on the debris flow plain screening
土石流平面篩分之試驗
作者: 陳虹合
關鍵字: 土石流
平面篩分裝置
出版社: 水土保持學系
摘要: 為解決一般透過性壩體所遭遇之最大問題,也就是容易受土石流巨大衝擊力而損壞及壩體上游貯砂空間不足,因而考慮設置平面篩分裝置。此平面篩分裝置由兩座相距很近的防砂壩上面再架設平行於流心線而有間隙的數十根H型鋼所組成,具有一般透過性壩體之特性,可調節土砂流出量,且沿著土石流流向設置,以避免土石流直接衝擊,並將貯砂場所移至下游,可有較大之貯砂空間。此裝置並針對分離後土石與水可能有再度混合形成土石流之缺點加以改良,創設主流及分流河道,使分離之較大礫石由主流河道至預計沉積處,分離出之細顆粒土砂及水從分流河道引導至下游原河道或安全地區排放。 本試驗之目的主要藉調整平面篩分裝置之設置坡度,了解在不同的設置坡度下,對土石流流動之停止及沉積有何影響。所得之結果有以下幾點: 1.土石流流況受平面篩分裝置作用,產生流動、停積、再流動、再停積之重覆現象,最後停止流動。 2.預計沉積處及平面篩分裝置上堆積之土砂,其粒徑分布呈現由下至上粒徑漸小之情形。 3.由試驗得知,平面篩分裝置之設置坡度在22度~24度時較為經濟,分離效果亦佳。
The dam body is damaged by the huge impaction from the debris flow and the sand-trapping capacity is not enough are the two challenges to the open dam. Therefore, this plain screening device has studied. This device composes of two dams with small spacing. Many structure steels I-beam are mounted on the two dams with designed spacing. The I-beam is parallel to the water flow. This device has the properties as the general open dam. This device can adjust the outflow of the debris and avoid the direct impaction from the debris flow. And some sand-trapping capacity can shift to the downstream. The device can form main channel and by-pass. The coarse cobble can move above the I-beam screen and deposit in the main channel downstream of the device. The fine particle and water of the debris flow will drop through the I-beam screen and flow through the by-pass to the downstream. The purpose of this experiment is to analyze the effect on stop and deposit of debris flow by adjusting the slope of the plain screening device. The results of this experiment are described as follows: 1.Due to the debris flow affected by the plain screening device, there is a repeated phenomenon of move and stop of the debris flow. And, at last, it stops. 2.The vertical distribution of the grain size shows that the higher the elevation the smaller the particle size. 3.From the experiment, we know that this device is economical and has better effect in separation for coarse cobble and fine particle when the slope is between 22˚ to 24˚.
URI: http://hdl.handle.net/11455/34128
Appears in Collections:水土保持學系

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