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

• Main Authors: Yi-JingChen, 陳懿靜
• Other Authors: Chjeng-Lun Shieh
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/52ekyb

碩士 === 國立成功大學 === 水利及海洋工程學系 === 107 === 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.