| Summary: | 碩士 === 國立臺灣大學 === 土木工程學研究所 === 94 === Chichi earthquake and Typhoon Toraji has caused severe landslides in Shitou area of Nantou, central Taiwan. Using the great amount of hazard data in Shitou area, we try to create the model reasonably and effectively simulating the landslide behavior in Shitou area. In this study, based on infinite slope model for slope-stability analysis, which assumed the slip surface parallel to the ground surface, a Geographic Information System (GIS) grid-based model is developed. The identification of back-calculation for the equivalent in-situ rock mass parameters of wide area is performed first by making use of geological strength index (GSI) and weakening the strength of rock mass resided in old landslide area. In addition, considering the rainfall-induced factor, we add a new parameter “m”, which is named ratio of groundwater depth and to be the function of accumulated rainfall, infiltration rate, porosity and soil depth. Combining the GIS deterministic grid-based model and GSI method, the safety factor between different grids will interact with each other. The balance process of the unstable forces between grids will keep going on until the safety factor is up to 1, which can decide the situation of grids - failure or non-failure but with potential of driving. The driving grids will move to the direction with maximum slope gradient and decide the source condition of the next flowing process, which keeps moment conversation in the whole process. The simulation process of landslide will end up by means of comparison between simulation outcomes and natural after-hazard sliding distribution. The results show that it can successfully simulate landslide migration behavior in Shitou area. In the future, the integrated GIS model on establishing the database system would offer the helpful reference for further research, hazard prediction and prevention works in Shitou area.
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