從長期監測資料建立降雨引致深層滑動預警模式-以清境及廬山地區為例

台灣位於環太平洋地震帶，經由歐亞板塊與菲律賓海板塊的相互作用下，造就了山坡地形豐富的特色，加上台灣屬於副熱帶季風氣候，對流雨、颱風等帶來豐沛雨量的同時，使得山坡地災害成為重要議題。本研究之研究範圍為廬山地區與清境地區深層滑動潛勢區，主要利用現地近10年的長期監測資料，探討雨量對深層滑動之影響以及其警戒值之訂定。降雨事件為深層滑動發生的主要誘因，本研究比較不同雨場切割方法對於地下水位變化影響，挑選出「前後24小時無雨」作為深層滑動主要雨場切割方法。雨場切割後之雨場累積雨量與地下水位回歸後，得到加快深層滑動速度之地下水位臨界值，再由回歸結果反算滑動臨界累積雨量為1000毫米，而本研究在邊坡位移中，採用GPS靜態基線解算結果，作為滑動趨勢的驗證分析。最後再利用此臨界雨場累積雨量影響後之地下水位，以極限平衡法與有限元素法進行邊坡數值模擬反算分析，找出最貼近於實際情況邊坡材料參數，進而模擬常時水位下邊坡穩定情形。在上述研究成果顯示，深層滑動之水位變化速度極為緩慢，因此在雨場切割方法中，如採用切割過細的方法，較無法顯著分析出深層滑動發生的降雨事件，而經過合適的雨場切割、長期監測資料分析與驗證所得到的臨界雨量、邊坡模擬材料參數以及分析流程，對於後續研究及實際應用有很大的助益。

關鍵字

降雨；深層滑動；監測資料；預警模式

並列摘要

Taiwan is located in the Pacific Rim seismic zone. The interaction between the Eurasian plate and the Philippine Sea plate has created a great amount of mountain feature in Taiwan. Because Taiwan has a subtropical monsoon climate, which brings torrential rain and typhoon with abundant rainfall, dealing with landslide hazards have become an important issue. The study area is the deep-seated landslide potential area in the Lushan area and the Qingjing area. The study uses the 10-year long-term monitoring data of the study area to determine the rainfall-affected on deep-seated landslide and the warning threshold. Rainfall events are the main cause of deep-seated landslide. This study compares the effects of different rainfield cutting methods on groundwater level changes, and selects “no rain 24 hours before and after” as the main method of deep-seated landslide main defining a rainfall event. By using the regression analysis of the accumulated rainfall and groundwater level changes, the threshold value of the groundwater level for accelerating the deep-seated landslide speed is obtained, and then the regression critical rainfall is 1000 mm. In the slope displacement, the GPS static baseline solution results are used as a verification analysis of the sliding trend. Finally, the groundwater level after the influence of the accumulated rainfall in the critical rain field is used, and the back-calculation analysis of the slope is carried out by the limit equilibrium method and the finite element method to find the material parameters of the slope which are the closest to the actual situation. Then, simulate the stability of potential landslide site is under the normal water level. The result shows that the speed of deep-seated landslide water level changing is extremely slow. Therefore, in the defining a rainfall event method, if the defining method is too sporadic, it is impossible to significantly analyze the rainfall events caused by deep-seated landslide, and after suitable defining a rainfall event. The critical rainfall, slope simulation material parameters and analysis process obtained from long-term monitoring data analysis and verification are of great help for subsequent research and practical application.

並列關鍵字

Rainfall ； Deep-seated Landslide ； Monitoring Data ； Warning Model

參考文獻

1.DavidJ. Varnes (1978)，Slope Movement Types and Processes

Google Scholar

2.Ministry of Land, Infrastructure and Transport Infrastructure Development Institute (2004)，DEVELOPMENT OF WARNING AND EVACUATION SYSTEM AGAINST SEDIMENT DISASTERS IN DEVELOPING COUNTRIES，Japan