泥石流沟的临界雨量线分布特征

本文采用聚类分析方法,对35条泥石流沟的临界雨量线进行讨论,找出了它们的分布规律。文中主要依据在泥石流沟观测的雨量资料,加上部分气象站、水文站的雨量资料,计算出雨强和实效雨量后作图。泥石流沟的临界雨量线,呈阶梯状分布。其趋势与泥石流的规模和性质无关,与泥石流沟的流域面积、主沟长度、相对高差和主沟床平均比降等因子关系并不密切;而与泥石流沟形成区的山坡坡度和泥石流发生频率较为密切,特别是它与泥石流提供固体物质的方式最为密切。

Distribution characters of critical rainfall line for the debris flow gully

The critical rainfall lines of 35 debris flow gullies are discussed inthis paper.Their distribution laws are found out by the cluster analysis.According to the rainfall data observed at the debris flow gullies andpartial meteorological observatories or hydrometric stations,the author mo-unted the rainfall intensity and effective rainfall, then draw thechart. The critical rainfall lines of debris flow gullies are distributed inladder. Its tendency has no relation to the scale or the characters ofdebris flow and it is not either closed with the basin area, the length ofthe main gully, relative difference of height and average gradient ofmain gully beds, etc. .However, it has a close relation to the gradient ofslope in the formation region of debris flows and their occurence fre-quences. Especially, it has close relation to the forms of supplying solidmaterial for debris flows.