A novel approach for slope stability evaluation considering landslide dynamics and its application to reservoir landslide

A novel and robust slope stability evaluation method based on energy method and radial slices method (RSM) is proposed and validated in terms of strength parameter sensitivity and determination of the critical sliding surface. The sensitivity analysis shows that the deviation from the limit equilibrium method (LEM) does not exceed 1.5%, demonstrating the feasibility of the proposed method. Different from LEM, the proposed framework gets functional enhancements: (1) This method considers the failure mode of the slope as a combination of translation and rotation, which is more in line with the actual monitoring results; (2) if the virtual displacement is regarded as a variable, the effect of accumulated displacement on slope stability can be studied; (3) if the factor of safety (FOS) for the slope is less than 1, this method can be extended to analyze movement of landslide mass after instability using the energy balance. Then, the proposed framework is applied to the 1963 Vajont event and Xinhua event to analyze the slope stability at the changes of reservoir water level and the dynamics after instability. Comparing slopes with different deformation patterns in calculating stability, the paper finds that permeability is the key to understanding the deformation response and summarizes the failure mechanism. For 1963 Vajont landslide, the proposed framework calculates the maximum velocity of the intermediate section to be 21.51 m/s, which is in general agreement with the inference by Hendron and Patton (Eng Geol 24:475–491, 1987), and superior to Zaniboni and Tinti (Nat Hazards 70:567–592, 2014)’s calculation of less than 20 m/s. Through research and application, the superiority of the proposed framework in analyzing slope hazards is shown.