Study on the Mechanism at Laitou Landslide Area by Earth Electrical Logging Method

• Main Authors: Chiang Hung Chuan, 江泓銓
• Other Authors: Chung-Li Hsu
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/83518564902255387401

碩士 === 國立屏東科技大學 === 水土保持系所 === 101 === In August 2009, Typhoon Morakot caused a large scale landslide at Laitou forest road, which is located on the south side of Longmei settlement in the upstream catchment of Zengwen Reservoir. Through the interpretation of satellite images over the years, the collapsed land was found to be pre-existing. Changchikeng formation is the main geological setting in this region. High erosion rate in the downstream area, unfavorable geographical conditions and influence of environmental forces may contribute to the continuous expansion of landslide area, which imposes threats to the safety of Longmei settlement. Regulation project for the disaster after Typhoon Morakot has been completed. Through monitoring the collapsed land from above and applying the Earth Electrical method to conduct relevant analyses, this research aims at understanding the distribution characteristics of Longmei settlement and the neighboring Laitou collapsed strata. According to the findings of the research, a subsurface displacement at 10 cm depth was observed (via an inclinometer) next to the ridgeline within the catchment of Laitou landslide area near Longmei settlement. Then, the Earth Electrical method was applied to plot the ρa–a resistivity image profile. The proposed slipping plane and slipping depth considerably matched the results derived from observing features of ρa-linear array of the profile: horizontal, vertical, closed, erected, waning and inflective, and from ground surface survey. By applying double logarithmic analysis on ρa–a curve patterns combined with core drilling data, strata for locations lacking drilling records can also be effectively classified in accordance with features such as linear rise, decrease, break of slope, tremor, vertical curve and inflection.