Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/33915
標題: 土石流支流入匯主河槽泥砂沖淤之研究
The Scour and Deposition of Main Channel Induced by the Tributary Debris Flow
作者: 李仲強
Li, chung-chiang
關鍵字: 土石流;Debris flow;輸砂;交匯機制;堆積扇;泥砂;Sediment transport;Junction mechanism;Alluvial fan;Sediment
出版社: 水土保持學系
摘要: 
The purpose of this study is to describe the tributary debris flow which flow into the main channel and deposite on the confluence, based on the flume experiment. In the tributary, the dry sediment and water were mixed to form the debris flow. This study shows that the formation of the alluvial fan included two primary processes which are separated by the apperance of the retrogressive deposition in the tributary outlet. In the process of the retrogressive depositing in the tributary, there are three typical patterns that the sediment continued to flow into the confluence to cause the expansion of the alluvial fan.
TypeI:Sediment was swept to the alluvial fan by hydraulic jump.
TypeII:A new debris flow which was formed above the mound of the tributary flowed into the alluvial fan.
TypeIII:As the excess pressure behind, the alluvial fan was pushed by the mound of the tributary.
The formation of Type III was analysed and discussed. The method which estimate the debris flow discharge in Type II was purposed. Finally, dimensional analysis is used to show the maximum deposition volume before the retrogressive deposition of the tributary appeared.

本研究透過實驗研究,探討土石流入匯主河槽之泥砂沖淤特性。支槽以乾砂加入清水混合的方式模擬土石流進入交匯口淤積。藉由實驗現象之觀查,本研究發現土石流支流入匯主河主要可區分為兩階段,第一階段為土石流初始進入交匯口流動後停淤之過程,第二階段為土石流支流開始發生溯源淤積,由於泥砂特性發生變化,支流在溯淤過程中會伴隨發生第二次土砂流動進入交匯口,造成堆積扇第二次範圍擴張。本研究根據土石流支流溯源淤積後發生第二次交匯口堆積扇範圍擴張之過程,提出3種主要分類:
TypeI型:支槽水躍捲砂流入堆積扇造成擴張
TypeII型:支槽新形成土石流流入堆積扇造成擴張
TypeIII型:支槽擠壓堆積扇造成擴張
藉由實驗觀察結果,經由理論分析提出Type II型新土石流入匯堆積扇頂部之流量計算方法;探討Type III型發生的原因與規律性;最後,藉由因次分析方法,分析支槽發生溯源淤積前主槽最大淤積泥砂量,提出一估算公式。
URI: http://hdl.handle.net/11455/33915
Appears in Collections:水土保持學系

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