三峡库水位上升后奉节县城李家大沟泥石流特征及危险性评价

The characteristics and risk assessment to debris flow in Lijia ditch Fengjie county after the water level rise in three gorges reservoir

奉节县城李家大沟为长江的一级支流,上游斜侧发育5条冲沟,源头发育2条支沟,曾于2001年和2002年暴发过泥石流。通过现场的调查和工程地质测绘,对主沟李家大沟泥石流的形成条件进行了分析。对泥石流沟的分区特征进行了探讨,共分成了形成区、流通区以及堆积区。在此基础上采用泥石流沟的数量化综合评判及易发程度等级标准,对泥石流的危险性进行了系统的评价和研究,其得分为80分,为轻度易发程度级别。

The Lijia Ditch in Fengjie county is a tributary of the Yangtze River.The inclined side in the upper part developed 5gullies,and the source part developed two tributaries.The debris flows out broke in2001 and 2002.Through the investigation and engineering geological survey of the scene,the formation conditions of the main debris flow in Lijia Ditch are analyzed.The zonal characteristics of debris flows are discussed.They are divided into forming area,circulation area,and accumulation area.On this basis,the comprehensive evaluation to the using number of debris flow gullies,the grade standards to easy happened degree of debris flows,and the risk of debris flows have been systematically evaluated and researched.The result score is 80 points,which belongs to mild susceptible degree level.This result can provide reference to the partition of debris flows,the formation mechanism,and the future design and control.