Evaluating the Effect of Toe Erosion on Slope Stability through the Integration of Hydraulic Model and Slope Stabilization

When heavy rainfall occurs in mountainous areas, the water level in streams rises, and the flow velocity increases, result in the enhancement of erosive capacity. As the fast-flowing water approaches the riverbanks, the stability of the riverbank slopes may reduce due to toe scour. It may further lead to the occurrence of near-bank landslides. The deposition of soil and sediment in the riverbed caused by landslides can have a major impact on the safety of the nearby residents and communities. The Erwanping landslide area in the upstream Ali Mountain watershed, Taiwan was selected as the research area. By the means of the CCHE-2D hydraulic model, flood simulations with return periods of 10, 25, 50, and 100 years were conducted in the river near the landslide areas. The scour of the riverbanks was analyzed. Subsequently, a slope stability model was established based on the post-flood bed elevation predicted by the CCHE-2D. The impact of toe scour of slopes on slope stability was evaluated through the changes of safety factor subjecting to floods of various return periods. The present approaches provide important information for development of disaster prevention and warning system in the riverbank areas.   Keywords: Riverbank, Landslide, Hydraulic model, Slope stability