請用此 Handle URI 來引用此文件: http://hdl.handle.net/11455/55893
標題: 氣候與地震劇變對堰塞湖演變機制及災害防治之研究-總計畫暨子計畫:堰塞湖對河川型態演變之影響
Influnece of River Morphological Development by Landslide Dams
作者: 陳樹群
關鍵字: 土木水利工程類
應用研究
摘要: 氣候變遷導致災害複雜化,例如堰塞湖與其所造成之災害已有逐漸增多之趨勢。堰塞湖的形成多是因為崩塌、地滑、土石流堵塞河道所致,因此天然壩的安全性遠不及以工程方法構築之人工壩,這也就是天然壩易產生潰決,以至於釀成巨災的原因。大多數的堰塞湖年限極短,主要潰決原因為溢流溯源沖刷。堰塞湖的壽命及潰決方式,受制於天然壩體大小、堵河之土砂材料特性、上游來水條件以及堰塞湖之蓄水容量等。2009 年8 月7 到9 日颱風莫拉克侵襲臺灣地區,超大的降雨造成東部與中南部的嚴重水患洪災,其受害規模與程度不亞於921 地震災害,使得山坡地的崩塌、地滑或土石流數量暴增,堆積土石堵塞河道形成了大大小小的堰塞湖,初步研判的新生堰塞湖有17 處。這些暴雨所形成之堰塞湖的壩身多矮而長,且在短時間內都發生過不同程度的潰決,而潰決的同時也造成河道的嚴重沖淤與水位變化,並且對下游村落造成一定程度之傷害,其中以小林村為甚。現存之堰塞湖則因均已溢流,雖然危險度已大幅降低,但建立完善的危機管理對策仍刻不容緩。本研究主要分為三部份,第一部份為蒐集彙整國內外堰塞湖資料及各期航空照片;並透過試驗方式,建立不同河寬、流量與支流入流之土石流濃度、粒徑等因素對壩體型態及組成之影響。第二部份為透過室內及室外試驗成果,建立各類型堰塞湖之形成與河川水流之交互影響機制,並探討堰塞湖之存在對河相之影響。第三部份為根據室內外試驗探討,堰塞湖潰壩後對河川上下游之河相改變;並利用河相觀點,探討堰塞湖災害發生時之工程決策及危機管理對策。
As other compound disasters due to climate change, the occurrence probabilities of thelandslide dam and its secondary disasters have been increasing gradually. The landslide damis formed mostly by rock fall, landslide and debris flow blocking river. The safety of thenatural dam is far below the artificial dam built by engineers, and the dam is apt to failure.The lives of most landslide dams are extremely short, due to overflow and headcutting mainly.The life-span and failure pattern of the landslide dam are affected by size of dam, soil material,inflow and capacity of the barrier lake etc. Typhoon Morakot attacked Taiwan in 7-9 Aug.2009 and brought heavy rainfall causing serious floods and 17 landslide dams in the east andcentral-south Taiwan, and caused a serious damage more than Chichi earthquake did. Mostlandslide dams overwhelmed within a short time, meanwhile caused flushing, and seriouschange on the river morphology, and even human injury and property loss in downstreamcommunities, such as Shiaolin village. Therefore, disaster mitigation and risk management oflandslide dam need a great attention in the future.This research is divided into three parts. The first part is to collect and coordinate thedata and every period orthophoto in the landslide dam region in the world. According to theexperiment results to develop the relationship between shape and composition of landslidedam from width, flow discharge, concentration of debris flow and grain size. The secondpart is to use the field and laboratory experiment results to establish the interactivemechanism of the form of landslide dam and flow pattern and to discuss the influence ofriver morphology when the landslide dam existed. The last part is to discuss the rivermorphological available adjustability after the landslide dam failure. Finally, use the rivermorphological theory to present the disaster mitigation and risk management of landslidedam, and propose short term and long term hazard mitigation methods for landslide dams.
URI: http://hdl.handle.net/11455/55893
其他識別: NSC99-2625-M005-002-MY3
顯示於類別:水土保持學系

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