九寨沟县干沟泥石流形成机制及防治工程评价

摘要

自20世纪50年代以来，九寨沟县干沟曾暴发过几次小规模的泥石流，对泥石流堆积区居民的生命财产造成了威胁。“5.12”汶川地震之后，干沟泥石流流域内岩、土体的原始应力状态发生改变，地质结构受到破坏松弛，为泥石流形成提供了大量的物源条件；加之近年来，四川盆地极端天气频发，降雨具有强度大、持续时间长的特征，为泥石流形成提供了强大的水动力条件。在地形地貌、物源和水动力条件均具备的情况下，2009年8月24日干沟发生历史上规模最大的一次的泥石流。泥石流暴发后，大量泥石流物质堆积在沟口，将下游金字河堵塞约20分钟，最后溃决冲毁乡村公路及大量耕地，造成直接经济损失达500万元。目前干沟泥石流已经演变为一条高频泥石流沟，在将来高强降雨作用下极易再次发生大规模的泥石流灾害。%Since the 1950s,Gan Gully of Jiuzhaigou country has been several outbreaks of small-scale landslides,Residents of the debris flow deposits pose a threat to life and property.After the “5.12” Wenchuan earthquake,rocks,soil of Gan Gully original stress state has changed,the geological structure is damaged and Relaxed,provides a large number of material source conditions for the formation of of debris flow, In recent years, Frequency of extreme weather in Sichuan basin, with intensity, long duration of the characteristics of rainfall, provides For a powerful debris flow hydrodynamic conditions of the formation. In the circumstances of the topography, material source and hydrodynamic conditions are available , Gan Gully occured once the largest in the history of landslides on August 24, 2009. After the debris flow, Formed the large accumulation of debris, and outburst destroyed a large number of rural roads and farmland at last, Bring about the loss of $5 million of direct economic. Currently Gan Gully has evolved into a high-frequency debris flow, Rainfall of high-strength easily happen arge-scale landslides disaster again l in the future.