川南红层地区泥石流形成过程与动力特征研究——以四川省屏山县牛儿包泥石流为例

DYNAMIC CHARACTERISTICS AND FORMATION PROCESS RESEARCH OF DEBRIS FLOW IN THE RED ZONE, SOUTHERN SICHUAN ——TAKE NIUERBAO VALLEY IN PINSHAN COUNTY AS AN EXAMPLE

红层地区泥石流因受典型的地层岩性及气候条件等影响,发育分布数量较少,探索这类特殊孕灾背景条件下的泥石流成因及特征具有一定的减灾意义。文章以四川省屏山县牛儿包沟泥石流为例,通过对该泥石流沟流域的地形条件、水源条件及物源条件特征分析,探索了红层地区泥石流的成因和特征,综合分析了泥石流的动力特征。研究表明:(1)流域地形高差大,沟道狭窄,沟谷较陡,沟道纵比降较大,为泥石流的形成提供了有利地形条件;(2)流域汇水面积较大,降雨集中短时间内为泥石流的形成提供了充足的水源条件;(3)流域内物源集中,短时间内能为泥石流发生提供充足的物源条件。最后通过泥痕法计算了上一次泥石流发生时的流量,并对计算了不同暴雨频率条件下泥石流的流量,提出了针对性的泥石流防治建议,为牛儿包沟泥石流灾害防治提供了可靠的数据。

Due to the effect of typical stratum lithology and climatic conditions, the debris flow in the red zone has a small number of development and distribution. It is of significance to reduce the cause and characteristics of debris flow under the background of special pregnancy. Taking the Niuerbao valley debris flow in Pingshan County of Sichuan Province as an example, through the analysis of the topographic conditions, water source conditions and provenance conditions of the debris flow basin, the genesis and characteristics of the debris flow in the red layer are explored, and the dynamics of the debris flow is comprehensively analyzed, feature. The research shows that:(1) the terrain topographic height difference is large, the channel is narrow, the valley is steep, and the channel longitudinal ratio drops greatly, which provides favorable terrain conditions for the formation of debris flow;(2) the catchment area of the basin is large, and the rainfall is concentrated. In a short period of time, sufficient water source conditions are provided for the formation of debris flow;(3) The concentration of sources in the basin can provide sufficient source conditions for the occurrence of debris flow in a short time. Finally, the flow rate of the last debris flow was calculated by the mud mark method. The flow of debris flow under different storm frequency conditions was calculated. The targeted debris flow prevention and control suggestions were put forward. which provided reliable data for the prevention and control of the Niuerbao valley debris flow disaster.