雨量、溪流電導度與地表位移之關聯性研究-以竹林大規模崩塌潛勢區為例

Study on Correlation of Rainfall, River Electrical Conductivity and Ground Surface Displacement-A Case Study of Potential Large-scale Landslide in ZhuLin Area

陳懿靜(Yi-Jing Chen)

指導教授 ： 謝正倫

國立成功大學/工學院/水利及海洋工程學系/碩士(2019年)

摘要

近年來全球氣候變遷，極端降雨事件頻傳，災害的影響規模與尺度亦比以往嚴重，例如2009年莫拉克風災導致甲仙鄉小林村的大規模崩塌災害。極端降雨事件衝擊著既有的臺灣防災系統，加劇災害造成的民眾傷亡與財產損失，尤其是大規模崩塌災害。因此，大規模崩塌的監測及預警成為目前政府防減災的重要議題之一。
本研究係透過降雨、溪流電導度與地表位移之間關聯性的探討，評估降雨或溪流電導度做為大規模崩塌災害發生指標的可行性。首先對大規模崩塌潛勢區之溪流電導度進行時間及空間變化的量測，分析溪流電導度的特徵變化。於時間變化的分析中，於集水區溪流下游設置自記電導度計儀器，進行長時間的電導度量測及資料收集，以掌握潛勢區的電導度基準及趨勢。於空間變化的分析中，量測溪流下游至上游水樣的電導度，以探討溪流電導度隨崩塌潛勢區遠近的變化。接著，蒐集鄰近雨量站觀測資料，探討前期降雨與電導度的關聯性。最後，本研究蒐集崩塌潛勢區的單頻GPS地表位移資料，探討累積地表位移、累積雨量及電導度之間的關係。
本研究發現鄰近崩塌區有較高的溪流電導度，一個月前期降雨量的變化對溪流電導度有顯著的影響。另外，累積雨量、累積地表位移和溪流電導度等三者有相同的變化趨勢，透過分析知道，半個月累積雨量對地表位移有顯著的影響。綜合研究的成果，可以知道溪流電導度的變化與累積雨量和累積地表位移有相當的關連性。所以，本研究建議鄰近崩塌區的溪流電導度可做為評估大規模崩塌潛勢區的活動性指標之一。

關鍵字

大規模崩塌 ； 溪流電導度 ； 地表位移 ； 前期降雨

並列摘要

SUMMARY
Extreme rainfall events have impacted the existing Taiwan disaster prevention system, especially large-scale landslide. Therefore, the monitoring and early warning of large-scale landslide has become one of the important issues for the government to prevent disasters.
This study explores the relationship between rainfall, river electrical conductance and surface displacement, and evaluates the feasibility of rainfall and river conductance as indicators of large-scale landslide disasters. Firstly, the time and space changes of the current electrical conductivity of the potential large-scale landslide are measured, and the characteristic changes of the current electrical conductivity of the river are analyzed. In the analysis of time variation, a self-recording electrical conductivity meter instrument is installed downriver of the river in the catchment area to conduct long-term conductance measurement and data collection to grasp the electrical conductivity reference and trend of the potential area. In the analysis of spatial variation, the electrical conductivity of the downriver river to the upriver water sample is measured to investigate the variation of the current electrical conductivity of the river with the potential landslide area. Next, collect observation data from nearby rainfall stations to explore the correlation between pre-rainfall and electrical conductivity. Finally, this study collects single-frequency GPS surface displacement data from the landslide potential area to explore the relationship between cumulative surface displacement, accumulated rainfall and electrical conductivity.
This study found that there is a high river electrical conductivity in the adjacent landslide zone. And the change of rainfall in the first month has a significant impact on the river electrical conductivity. In addition, the accumulated rainfall, accumulated surface displacement and river electrical conductance have the same trend. Through analysis, it is known that the cumulative rainfall in half a month has a significant impact on surface displacement. Based on the results of the comprehensive study, it can be known that the change in the river electrical conductivity is quite related to the accumulated rainfall and accumulated surface displacement. Therefore, this study suggests that the river electrical conductivity adjacent to the landslide zone can be used as one of the activity indicators for assessing potential large-scale landslide areas.

並列關鍵字

Large-scale landslide ； River electrical conductivity ； Surface displacement ； Pre-rainfall

參考文獻

http://dx.doi.org/10.1002/9780470172766

參考文獻

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