灰色系统理论在北京山区泥石流危险度评价预测中的应用

泥石流灾害是北京地区严重的地质灾害之一。其危险度的评价与预测对防灾减灾意义重大。文章根据灰色系统理论的多因素关联度分析法，进行泥石流沟危险度评价。泥石流的形成暴发是多种因素相互作用的结果。多因素关联度分析就是要找出这些因素与泥石流的密切关系程度，根据各因素对泥石流作用的大小，做出综合评判。文章应用泥石流发生的重要参数——物质冲出量、流域面积、相对高差、沟谷切割深度、沟床纵坡、植被覆盖度、土层厚度、形成区山体平均坡度、降水量、崩滑塌密度进行关联度分析，将泥石流的各影响因素与泥石流规模、发展态势的紧密程度做定量分析，以此衡量各因素与泥石流之间的关联程度，寻找主、次因素。各因素按不同数量等级划分为危险、较危险及一般3个条件值，并给予3个级别划分值。再根据各因素所占权重获得各量级得分，通过泥石流各因子权重、因素量级划分及评分标准，对北京市816条沟谷进行了危险度评价。确定危险沟谷104条，较危险沟谷542条，一般危险沟谷170条。在此基础上，结合泥石流沟危害目标的性质、灾害损失及保护价值，进行泥石流危害程度评价，确定危害严重沟谷41条，较严重沟谷331条，轻微沟谷444条。预测结果与实际情况较吻合。

Grey system analysis and its application in the forecast of mud-rock flow criticality of Beijing

Mud-rock flow is one of the most catastrophic disasters in Beijing, so forecast and estimate of its criticality is substantial in the hazard resistance and anti-disaster. Based on the multi-factors correlation analysis in Grey System Theory, the paper evaluates the criticality of mud-rock flow. The mud-rock flow is the combination of many controlling factors including mass, drainage areas, relative altitude, valley depth, valley bed longitudinal slope, vegetations, the thickness of the layer, average inclination of the terrain, precipitation, density of slump mass. The paper makes the quantificational analysis on correlation between the controlling factors and the scale and development of mud-rock flow in order to separate the major controlling factors. Every controlling factor is divided into three grade:severe, dagerous, and light, and the criticality of a valley is the summation of grades of all controlling factors. According to the weights of the major controlling factors, the criticalities of 816 valleys have been evaluated:the number of valleys with high criticalities is 104, danger 542, and general 170. Together with consideration of the nature of the dangerous areas, losses in the mud-rock flow, and protection values, the criticalities are evaluated further as follows:40 valleys are graded into severe, 231 are danger, and 499 are light. The result accords with the fact of most valleys.