基于可拓理论的西南典型山区泥石流的危险性分级

Hazard classification of a typical southwest mountain debris flow based on extension theory

泥石流是西南山区较为常见的自然灾害,泥石流危险性的准确分级对于实现泥石流防灾减灾工作具有重要意义.目前,常用的分级方法是选取固定的几个指标,采用打分等方式进行评分等级.但有些分级计算方法不能根据实际地质情况灵活地选取分级指标,而且有些分级指标之间存在相互影响.本文将可拓理论方法和泥石流危险性分级相结合,建立基于可拓理论的泥石流危险性分级法.该方法主要是通过选取能够反映和体现泥石流危险性分级的各项重要参数指标——泥石流规模、发生频率、松散堆积物储量、主沟长度、流域面积、主沟平均比降、流域最大相对高差、泥砂补给段长度比和24 h最大降雨量,然后在物元理论、可拓集合论和关联函数运算的基础上,建立危险性分级的物元模型;并采用权的最小平方法确定各项参数的权重;通过实际的泥石流危险级别关联度的计算,最终确定危险性级别.通过可拓理论危险性分级的实际应用表明,该方法在泥石流危险性分级中有较好的适用性.

The debris flow is a common natural disaster in southwest mountain areas. Accurate classification of debris flow risk has a great significance for local government to prevent or mitigate the disaster. At present, the common classification method is used to select a few indicators, then to assign some values and to make rele- vant classifications. But some classification methods cannot flexibly choose the classification geological inde- xes, and some classification indexes can influence each other. This paper combines the extension theory meth- ods with the risk classification of debris flow. It establishes the method of risk classification for debris flow based on extension theory. The method mainly selects the important parameters of risk classification indexes that can reflect and embody the feature, the scale of debris flow, the reserves of loose accumulation, debris flow frequency, drainage area, length of main ditches, the maximum relative altitude in drainage area, the av- erage slope of main ditches, length proportion of debris supplement and maximum rainfall in 24 hours. Then based on matter element theory, extension set and dependent function calculation, the matter element model of risk classification is established. And the factor weights were determined using the minimum square method. Itfollows the determined has a good degree of association calculations for the actual risk classification. The final risk classification can Through the practical application of the risk classification based on extension theory, this method applicability in the risk classification of debris flow