Multi-Method Dynamic Analysis Of The Maoxian Rockslide-Debris Avalanche

A catastrophic rockslide-debris avalanche occurred in Maoxian,Sichuan on June 24,2017.Based on field investigation,remote sensing images,seismic signal and numerical simulation,the runout behavior of the Maoxian rockslide-debris avalanche was analyzed.Main research work and achievements of this paper are as follows:?1?Spatial partitioning of the debris flow was obtained according to the remote sensing and images before and after the event.In order to study the dynamic characteristics of Maoxian rockslide-debris avalanche,a three dimensional numerical model built by the satellite imagery was used to simulate this event.?2?The intensity of the strong motion and time-frequency signature of the generated seismic signal produced by Maoxian landslide were analysed and the results indicated that the duration of the movement is estimated at about 120 s.Also,the movement process of the debris flow can be divided into initial breaking stage,impacting-spreading stage and slow braking stage,and each stage lasts approximately 40 seconds,60 seconds and 20 seconds respectively.Based on the HHT transformation,the stage of violent fragmentation is 50-70 s.?3?Based on the movement distance and characteristics at different time steps of the Maoxian landslide,numerical simulations were conducted through DAN^3D and MatDEM.The accumulation distribution,erosion distribution,velocity distribution,variation of the energy,heat energy distribution,movement distance and velocity of monitored particles and some other dynamic characteristics were obtained through comparing the simulated results with the actual situation.The comparison results illustrate that DAN^3D is more suitable for the prediction of a landslide,as it has high calculation efficiency and gave more accurate results of the scale,movement path and deposit distribution of the landslide.In addition,MatDEM is more suitable for the mechanism research and prevention of the landside,because it can simulate the generation,variation and distribution of the energy and the micro-motion properties of particles in the movement process of the debris flow.?4?DAN^3D was used to predict the movement process of potential unstable rock mass with the volume of 300×10⁴ m³ on the west side of the landslide area.Results indicated that the sliding process has a duration of approximately 60 s with a maximum velocity of 36 m/s,and the displaced materials travelled about 700 m and the final volume of the sliding mass is about 435×10⁴m³.