长江上游陇南地区泥石流沟形态非线性分析

Nonlinear analysis on morphological factors of debris flow gullies in Longnan area

以长江上游陇南地区405条泥石流沟为例,经统计分析,得出沟道汇水面积为2~15 km2、沟道比降为5%~35%、沟长度为1~15 km的沟道最容易发生泥石流。同时泥石流沟的汇水面积、沟道比降和沟道长度均存在明显的分形特征,3个形态要素与沟道数目之间具有良好的非线性关系,其分形维数依次为1.124,1.489和1.239,分维的大小反映了不同形态要素对系统所起作用的差异。其结果对长江上游流域泥石流灾害的进一步研究与防治提供了新的思路。

A statistical analysis is carried out for 405 debris flow gullies in Longnan area, upper Yangtze River, and it is re-vealed that the gullies with several characteristics are most likely to develop debris flow, especially for the gullies with a drainage area of 2~15 km2, gully gradient of 5% ~35% and main gully length of 1~15 km. Simultaneously, there is obvious fractal characteristics in the these morphological factors with fractal dimension of 1. 124, 1. 489 and 1. 239, all which have fine nonlin-ear correlation with the number of gullies. Different morphological factors play different roles in the gully system, which can be reflected by the amplitude of fractal dimension.