Abstract:

Highspeed long runout landslidedebris flow is one of the most destructive failure modes of large unstable rock，which can be fast launching, run long distance and cover large area, so the runout prediction research of large unstable rock has great practical significance. Taking the Daxiang unstable rock as a study case, this project aimed at predicting the dynamic characteristics of long runout landslidedebris flow. Based on geological and geomorphological survey，the development characteristics and failure pattern of Daxiang unstable rock were analyzed. The DAN3D code and the rheological parameters calibrated through the inversion analysis of Jiweishan landslide were used for the analysis of the Daxiang unstable slope. The simulation results show that (1) the movement process of rockslidedebris avalanche could be divided into four stages as launching, deflection and throwing, crash and erosion, and long range accumulation. The whole process took 220 s, and travel distance was 2500 m; (2) the volume of the sliding mass was 530×104 m3, the total volume of the accumulation was 790×104 m3, the length of the accumulation was 1680 m and average depth was 6 m, the maximum erosion depth along the path was 8 m, and the maximum velocity was 60 m/s; (3) the debris could go though Yangjiao Town and reach the Wujiang River, which implies that the Yangjiao Town is in the danger zone; and (4) the simulated prediction could be used as a reference for landslide hazard quantitative assessment.

Key words: Yangjiao Town, rockslidedebris avalanche, DAN3D, rheology model, runout analysis