Vol19 No.6: 1495-1508
【Title】Behaviouralanalysis and dynamic simulation of the debris flowthatoccurred inGanluo County (Sichuan, China) on 30 August 2020
【Author】LI Nuo-dong1; LIU Wei2,3,4*; ZHAO Jin-heng5
【Addresses】1 Chengdu Power Supply Company of State Grid Sichuan Electric Power Company, Chengdu 610041, China; 2 Key Laboratory of Mountain Hazards and Surface Process, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China; 3 University of Chinese Academy of Sciences, Beijing 100049, China; 4 State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China; 5 Department of Water Hydropower and Construction Engineering, Skill Training Center of State Grid Sichuan Electric Power Company, Chengdu 610000, China
【Corresponding author】LIU Wei
【Citation】Li ND, Liu W, Zhao JH (2022) Behavioural analysis and dynamic simulation of the debris flow that occurred in Ganluo County (Sichuan, China) on 30 August 2020. Journal of Mountain Science 19(6). https://doi.org/10.1007/s11629-021-7199-z
【Abstract】On August 30, 2020, a high-intensity stormthat dropped45.4 mm of rain in 5 hours hit the Heixiluo basin and triggered a landslide-generated debris flow event, causing fatalities and damage. The original source of the debris flow was a large slope collapse on a steep hillside. The fallen debris mass was enlarged through sediment entrainment and slope collapse and ultimately buried a bridge atthegully entrance. Approximately6.9×105 m3 of material,including sediments and collapsed slope depositsin the gullies,was entrained,and the maximum erosion depth reached17 m. A geomorphological analysis was initially performed based on a detailed field investigation to recognize the liquid and solid sources of the debris flowand the areas subjected to deposition and erosion. A map of the erosion-deposition distribution was obtained based on pre- and post-event DEMs. Using the rainfall estimated by the nearest rain gauge and the solid source estimated by the DEMs, runoff and debris flow propagation was simulated using a liquid-solid two-phase model that considers the effects of runoff and entrainment. The similarity between the estimated and simulated deposition-erosion volumes wassatisfactory. The behaviour of debris flowscaptured in the simulation is broadly in line with the main features of the observed event.
【Keywords】Debris flow; Formation analysis; Two-phase model; Dynamic simulation