Numerical analysis of slope stability at the 115.9 k point of the Su-Hua highway

The Su-Ao to Nan-Ao section of the Su-Hua highway was seriously damaged by rain-fall caused debris sliding during the 2010 typhoon Maggie. Rain-fall induced debris slide damage was most significant at kilometer 115.9, which is the area of maximum curvature of the highway. Slope instability and landslide hazard potential are key issues for disaster prevention along mountain roads. In this study, the finite element software (Midas/GTS) has been used to establish a three-dimensional slope stability model of the slope at kilometer 115.9 of the Su-Hua highway using model parameters based on field investigation and reasonable assumptions. Field survey and numerical simulation results reveal landslide failure mechanisms, the area of the potentially unstable slope, and sliding depth, which otherwise are difficult to obtain. The study shows that the area and volume of the landslide body is approximately 1.56 × 10-1 km2 and 3.56 × 10-3 km3, and that the deepest sliding depth is 22.2 m. These results can provide a reference for disaster prevention geologic hazard mapping, and associated remediation project planning.