某水电站库区骆驼沟泥石流成因分析及危害性评价

西南地区某水电站库区骆驼沟为大渡河的一级支流,2005年7月爆发了一次大规模泥石流,彻底摧毁了进山公路,改造了与大渡河交汇处至以上1.6 km长的堆积区地貌,迫使骆驼沟改道,幸未造成人员伤亡。骆驼沟流域面积大,纵坡降缓,沟谷开阔,是一条比较成熟的河流,但却发生了较大规模的泥石流,通过调查分析,认为主要有三方面原因：（1）支沟垄龙沟距主沟沟口很近,且为一条典型泥石流沟,能够为主沟泥石流的发生提供大量固体物质来源;（2）主沟汇水面积广,可形成大规模洪水,为泥石流的发生提供了强大的水动力条件,能将垄龙沟大量固体物质带到沟口;（3）强降雨因素。此外,从地形条件及物源储量来看,骆驼沟泥石流正处在发展阶段,对沟口公路干线、居民建筑物依然存在较大的威胁,但对水电站库容影响很小。

The Genetic Analysis and Harmfulness Evaluation of Luotuoguo Debris Flow in Reservoir Area of Some Hydropower Station

The Luotuoguo is a primary distributary of Dadu River which locates in the reservoir area of some hydropower station in the southwest of China. In july of 2005 year, a large-scale debris flow occurred in Luotuo channel, which completely destroyed the main maintain road. At the same time, it still rebuilt the shapes of accumulation zone from the cross of Dadu River and Luotuo channel to the inner of Luotuogou, which length is about 1.6 km, and made the main dyke change its course. But luckily it had not made one person casualty. In fact, the drainage area is broad, the longitudinal slope is flat, and the channel is open. All this indicate that the main channel is a mature river. But the large-scale debris flow has happened. Base on the investigation, the paper analyzed three aspects reasons. One is that the Longlonggou is a typical debris flow trough, which is a branch of main channel and locates in the site nearby main channel outlet, and can provide a great deal of substances. Second is that main channel has broad drainage area, and it can form large-scale flood. This is a strong hydrodynamic condition, and can carry vast scale solid matter. Third is the factor of intense rainfall. Furthermore, according to the landform and substance reserves, Luotuogou debris flow is at the stage of development, and still threatened the road main line and resident buildings. But it has little influence on reservoir capacity of the hydropower station.