岷江野牛沟泥石流形成机制及堵河分析

通过现场调查,对野牛沟泥石流形成条件、灾害特征、启动机理进行分析,并研究未来堵河可能性以及发展趋势。结果表明:野牛沟在"五一二"汶川地震后演化为一条泥石流沟,具有持久性、阵发性、支沟群发等特点,野牛沟泥石流的启动是因为"消防水管效应",水流快速集中为沟道径流,强烈冲击沟道物源,导致泥石流的形成,形成过程分为冲击启动—流通加速、溃决—泥石流堆积三个阶段,在暴雨频率为1%(及以上)时爆发泥石流可能堵塞岷江。

Formation mechanism and river blocking analysis of Yeniu gully debris flow in Minjiang River

The Yeniu gully in Wenchuan country outbreaked a debris flow on July 3,2011.It blocked the 2/3 of channel Minjiang River, causing huge economic losses.This paper analyzed the formation conditions, disaster characteristic and the formation mechanism according to the field investigation.This paper also studied the possibility of blocking the river and the trend of development. The results show that the Yeniu gully changed into a debris flow after the 5.12 Wenchuan earthquake.The characteristics of it are persistence, paroxysm and group occurrence. The initiated process can be summarized "fire-pipe effect". The overland flow of water concentrated into steep channels runoff and sources from gully-bed loose deposits. The forming process can be divided into three stages: shock starting phase, acceleration crevasse phase and accumulation phase. It can cause river blocking when the debris flow is excited by P=1% and above.