贵州望谟纳包沟泥石流特征及成因分析

2011年6月5日至6月6日,贵州望谟县发生连续强降雨,引发境内纳包沟泥石流灾害,给当地居民的生命和财产造成巨大损失。本研究着重分析了纳包沟泥石流的物源、地形和降雨因素,指出该地区降雨强度大,流域内30°～40°坡度范围比例最大,最有利于浅层滑坡的发育,滑坡进而为泥石流的暴发提供主要物源;进一步得出泥石流的特征和动力学参数,泥石流为稀性泥石流,最大洪峰流量25 m3/s,泥石流一次冲出固体总量约6 100 m3。该次泥石流的形成机理为浅层滑坡引起的滑坡型泥石流。针对纳包沟的特点,当地政府和居民都应高度重视并实施相应的生物和工程措施以预防泥石流的发生。

Analysis on the Characteristics and Mechanism of Debris Flow in Nabao Gully of Wangmo, Guizhou

A heavy rainfall was triggered in Wangmo County,Guizhou Province on June 5-6,2011.A debris flow was broken out in Nabao gully in this area,and caused plenty of damage.This study analyzed the source,topography and rainfall conditions of debris flow,and revealed that the large intensity of rainfalls and the large proportion of slopes in the range of 30°-40° were the triggering reason of shallow landslides,and the landslides provided the solid sources of debris flow.The characteristics and dynamic parameters of the debris flow are concluded as follows: the debris flow is one of the less viscous debris flow;the peak discharge is 25 m3/s,and the total volume of debris flow is about 6,100 m3.The debris flow in Nabao gully was induced by shallow landslide.In the light of the characteristics of Nabao gully,the local government and resident should attach great importance to these and take the corresponding biological and engineering measures to prevent debris flow.