降雨導致邊坡滑移之預警模式建立

台灣地處地質破碎帶，造山運動頻繁，使得山地地形多，亦常伴隨地震，又位處亞熱帶季風氣候區，多有颱風豪雨侵襲，這樣的環境條件下，易發生崩塌、土石流災害。面對無法避免之天災侵襲，為了能保障更多山區居民之生命及財產安全，在災害發生前能做出提早的警示及疏散避難，成為重要之課題。　　本研究欲探求研究區域之崩塌地滑機制，並建立其預警模式。整體研究區域預警模式建立之方法流程，主要分為幾個步驟 :以歷年航空照片進行影像解算後建置正射影像及數值地形模型，進行地表高程變形分析，找出研究區域內潛在或有明顯崩塌區域；以現地監測資料，迴歸分析出降雨如何對區域邊坡之水位變化與變形量造成影響；利用地表、水位、岩層界面高程建立邊坡剖面模型，進行極限平衡法與有線元素法之分析，分析因降雨而上升之水位對坡體穩定性的影響與潛在變形量。　　本研究以南投縣仁愛鄉廬山地區之預警模式建立為目標，過去調查發現其為深層滑動之邊坡，監測亦顯示其持續滑動情形，本研究建立該處之崩塌機制，進而設計符合研究區域之黃、紅警戒值，並建立預警模式，期為相關單位所用。

關鍵字

降雨；地下水位；邊坡模擬；預警模式

並列摘要

Taiwan has lots of mountains because of locating in the geological fracture zone where orogeny often happens. Typhoons and earthquakes usually induce landslide hazard. Since some of the disasters may not be prevented, to protect residents’ lives and property in the mountain area, effective warning-evacuation systems alert the local people before landslide is an important issue. 　　Landslide hazard mitigation is aim of this study. This research will identify the slope mechanism of the study area and establish warning alert system. First, use photos to build the orthophoto and numerical terrain model. The results will find the landslides region in this area. Second, by organizing the slope monitoring data, the study can figure out the equation of the relation between accumulated rainfall and the raise of the groundwater level and slope deformation.A slope model has been established to do limit equilibrium analysis and deformation with FEM. 　　The scope of this research is using Lu-Shan landslide, located in Ren-ai township, Nantou County as study area. The area, has been found having a potential deep seated landslide and field monitoring data also has the same evidence. Failure mechanism of the study area has been established and warning model has been established. A yellow/red warning mechanism has been established based on this study and hopefully can be used for government.