Slope stability analysis under extreme rainfall in slate slope
劉冠麟(Kuan-Lin Liu)；盧之偉(Chih-Wei Lu)；林宏明(Hung-Ming Lin)
深層崩塌 ； 極端降雨 ； 板岩 ； 累積降雨量 ； Deep-seated landslide ； Extreme rainfall ； Slate ； Cumulative rainfall
|Volume or Term/Year and Month of Publication||
11卷1期（2019 / 03 / 01）
19 - 32
With global warming and climate change issues, extreme rainfall events in the future may become the normal, causing severe disaster events will be more frequent. During the rainy season such as typhoon and heavy rain, severe rainfall often induces more serious slope disasters. Analysis of the devastating heavy rainfall in Taiwan in the past two decades, the occurrence of slope disasters is mostly caused by ＂excessive continuous rainfall＂ or ＂short-duration rainfall＂. For mild metamorphic slate, its erosion resistance is higher than that of mud or shale. However, the slate is easily split along its cleavage direction and turned into a finely-cut sheet. When subjected to long-term gravity and weathering, the material of shale will gradually become weaken and turn into creep. That is, during the deformation process of slate slope, joint fissures will gradually grow out. When the rainfall infiltration leads to groundwater level rise, the possibility of rock debris collapse will increase. In this study, high- risk areas with deep collapse were selected for analysis, taking Songmao Landslide area in Lishan District as examples. To simulate groundwater level rise caused by rainfall, this study conducted SEEP/W module of GeoStudio numerical software. The groundwater level monitoring data will be used for verification. Then, the SLOPE/W module of GeoStudio numerical software is used for slope stability analysis. Exploring the relationship between groundwater level rise and safety factor of slope is one of the main task in this study. The uncertainty of rainfall caused by extreme weather is researched herein. In this study, the design of rainfall patterns such as advanced, intermediated, delayed and uniform rainfalls models were simulated. This study tried to establish a deep- seated landslide disaster warning system. After simulation analysis and verification, the relationship between rainfall duration and accumulated rainfall and the relationship between the maximum groundwater level cumulative rainfall and water level elevation were proposed as the evaluation criteria.