3D Numerical Simulation Of The Airblast Generated By Donghekou Rock Avalanche

Donghekou rock avalanche, in Qingchuan Country, Sichuan Province, buried four villages and a power station at the bottom of valley, leading to 780 people’s death. The landslide mass blocked the Hongshi River and Qingzhu River and generated two dammed lake.In this thesis, based on the assumption of equivalent fluid for debris flow, author simulated the whole movement process of the landslide by using the computational fluid software, and analysed the characteristics of airblast generated by Donghekou rock avalanche. The main conclusions are as follows:(1)The whole movement process of Donghekou rock avalanche is about 63 seconds. The total displacement is more than 2400 m. At the 27th second, the slide speed reaches the maximum value of about 43.3m/s. During the whole movement process, most of time the fastest speed area is close to the front part of the sliding body. Generally, the speed of front part of the sliding mass is far greater than the rear part of the sliding mass. However, during the 40th to 48th second, the front part of the sliding mass begin to slow down since the middle of the sliding mass move to a central platform in the path. Due to the rear part of the sliding mass is still at the top of the steep ridge, the speed of the rear part of the sliding mass is faster than the front part. During the 61st to 63nd second, since the sliding mass is approximately stopped, the speed of front part is very small. However, the rear part of the sliding mass just goes off the central platform which still has great kinetic energy, so the speed of the rear part of the sliding mass is faster than the front part.(2)At the 27th second, the speed of slide mass got the fastest value, and the airblast caused by rock avalanche also got a maximum of speed of 35.1m/s and pressure of 681Pa. In the path, the airblast decreased with exponential trend, with sharply reduction in 200m range ahead of the debris flow.(3) Topography along the path has a significant effect on the velocity and pressure of airblast. The terrain is much gentler and broader, the velocity and pressure of airblast are much lower.