(1.四川省自然资源勘察设计集团有限公司，四川成都 610051;2.成都理工大学地质灾害防治与地质环境保护国家重点实验室，四川成都 610059)
(1.Sichuan Natural Resources Geological Survey and Design Group Co., Ltd., Chengdu 610051, China; 2.State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu610059, China)
As one of the most disastrous geological disasters in the cryosphere, ice avalanche has the characteristics of complex movement process, high difficulty in prediction and serious disaster consequences. On July 17 and September 21, 2016, two giant ice avalanche-debris flow events occurred in Ali Prefecture, Tibet, which caused serious harm to the life and property safety of local residents and the ecological environment, so PFC3D was used to invert the two ice avalanche-debris flow motion processes, and on this basis, the potential ice avalanche-debris flow danger in the surrounding area were simulated and predicted. The results showed that: (1) the movement time of the two ice avalanche-debris flows was 300s and 240s, the peak average velocity of particles was 32.05m/s and 34.80m/s, respectively, and the volume of the first ice avalanche into the lake was about 8.47×106m3. (2) The energy transfer at the front and rear is the key mechanism for high-speed long-range movement of ice avalanche-debris flow; (3) It is predicted that the area of the main accumulation area on the northwest side is about 1.1km2, the area of the small accumulation area on the northeast side is about 0.3km2, and the total area of the danger area is 3.28km2 after the ice avalanche of the Aru 85 glacier(hidden danger of ice avalanche), which has certain scientific value and practical significance for the ice avalanche disaster prevention and mitigation work on the Qinghai-Tibet Plateau.