Slope Stability Analysis Of Transient Seepage Under Extreme Climates: Case Study Of Typhoon Nari In 2001

Abstract

The effects of climate change, the inherent fragility of geological structures in Taiwan, and questionable developmental practices have led to the occurrence of numerous slope disasters, most of which were triggered by the extreme rainfall associated with typhoons. Therefore, this study collected rainfall data associated with typhoons striking northern Taiwan over the last 17 years, as a follow up to estimating database of extreme rainfall events. Most previous investigations regarding the impact of storms on slope stability focused on solutions with conditions, such as static groundwater levels or steady pore pressure. Previous studies have used software STABL to analyze slope stability but failed to consider the influence of groundwater seepage or changes in pore pressure during rainfall events. Thus, we proposed an improved method of defining a partitioning rainfall to select the most representative rainfall events, whereupon a comprehensive overview of the associated rainfall patterns was constructed using finite-element analytical software SEEP/W. We simulated the transient seepage of unsaturated soils and input the results into SLOPE/W to conduct slope stability analysis. A comparison of STABL results demonstrates that the outcomes of this study are more applicable to real-world cases than existing methods for the evaluation of slope stability.