南水北调西线一期工程区泥石流发育的非线性特征

通过对研究区103条泥石流沟发育状况统计显示，泥石流沟的数目、发育密度及规模在不同流域表现出不同特点；综合分析表明。泥石流沟的流域面积、主沟长度及平均沟床比降存在明显的分维特征，泥石流堆积物粒度组成具有很好的分形结构，这种良好的非线性关系在一定程度上揭示了研究区泥石流发育的非均一性和自相似性；分析得出了在沟谷流域面积〈5km^2，主沟长度〈5km及主沟平均沟床比降10％～60％时研究区内泥石流最易暴发的结论。

Non-linear characteristics of debris flow development in the area of the 1st-stage project of west-line for transferring water from Southern to Northern China

Comprehensive investigation and systematic research on the debris flows in the area of the 1st-stage project of West-line for transferring water from Southern to Northern China have been conducted. It has been found that there are 103 debris flow gullies. The number, distribution density and scale of debris flow gullies have different characteristics in different drainage. According to fractal geometry, there are fractal structure features of the deposits of debris flow. Results show that the fractal dimension (D) changing from 2 to 3. Fractal dimension denotes properties of debris flow accumulation as a self-organizing system. Simultaneously, there is an obvious property in drainage area, main gully length and slope ratio which also have fine no-linear correlation with debris flow number. By analyzing, debris flow will be easy to occur when the drainage area is <5km2, the mail gully length <5km and the average gully slop ration <60%.