The investigation and analysis of DaGuan large-scale landslide area, He-Ping district, Taichung city

• Main Authors: Hao-Chih Liao, 廖浩智
• Other Authors: Hsun-Chuan Chan
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107NCHU5080019%22.&searchmode=basic

碩士 === 國立中興大學 === 水土保持學系所 === 107 === The geological conditions are fragile and steep in Taiwan. After the 921 earthquake, the earth in many areas were loosened, which could easily trigger landslides and debris flow in the event of heavy rains, and then cause the major disasters in the middle and lower reaches. The Da-guan tribe is located in the upper part of Da-an River, has a lot of people, and it’s also an important economic fruit producing area of the aborigines. According to the results of the geological survey in 2011, the top of the Da-guan tribe is a potential large-scale landslide area. If the landslide occurs, it will threaten the safety of properties and human being. Therefore, this study takes the large-scale landslide in Da-guan as a research area. According to the slope, the collapsed land is divided into top, belly and toe. Through collecting geography and hydrological data could observe the basic characteristics of the sample area, and then could set the geological drilling and instrument to measure slop movement. In order to understand the displacement of the landslide during the observation period, the inclinometers were separately set in the top, the belly and the toe of the slope. By comparing the time and location of the stratum displacement during the observation period and the result of the amount of rainfall and underwater level, the reasons for the collapse of each part in the landslide area may be analyzed. The analysis results show that the sliding phenomenon in the top of the slope is between 20 meters and 30 meters below the surface, which is a broken sandstone shale, and the sliding phenomenon tends to be obvious when the groundwater level rised. It is mean that groundwater and geological factors is the main cause of the sliding of this section； the belly and the toe of the slope haven’t obvious stratum displacement, but the groundwater level is very high, which may affect the stability of the slope. The method explores the reasons for the possible collapse, and can provide a reference for the future partition control scheme for preventing landslide.