基于熵值理论的泥石流评价因子选取

针对地质灾害危险度评价中评价因子权重确定方法的缺陷, 依据最小熵分析理论, 将评价因子形成线性无关的成分, 根据评价因子对泥石流系统贡献率的大小进行评价因子优选与权重的确定, 将权重代入经典的泥石流危险度评价模型进行评估, 并将评估结果与计算结果进行了对比。分析结果表明: 优选出的主要评价因子为一次泥石流最大冲出量、频率、流域面积、主沟长度、主沟床弯曲系数、植被覆盖率、松散固体物质储量、流域切割密度和泥沙补给段长度比, 得到的权重分别为0.235 3、0.235 3、0.079 1、0.079 1、0.079 1、0.079 1、0.073 0、0.073 0、0.073 0;极度、重度、中度和轻度危险的泥石流沟分别为3、3、6、0条, 评价结果与研究区泥石流的实际情况和发展趋势吻合度较高, 从而证明将最小熵分析理论应用到地质灾害评价领域的可行性。

Evaluation index selection of debris flow based on entropy value theory

Aiming at solving the deficiencies of index weight determination in evaluating risk of geological disaster, the theory of minimum entropy analysis was used to form nonlinear independent components.The index optimization and weight determination were done based on their contributions to debris flow.The index weights were evaluated in the classic debris flow risk evaluation model.The evaluation results were compared with the calculated results.Analysis result shows that the main optimal indexes are the maximum rushed amount for a debris flow, frequency, basin area, main gully length, main gully bed tortuosity coefficient, vegetation coverage, the reserve of loose solid material, basin cutting density and sediment supply length ratio.The corresponding weight values of these indexes are 0.235 3, 0.235 3, 0.079 1, 0.079 1, 0.079 1, 0.079 1, 0.073 0, 0.073 0 and 0.073 0 respectively.The numbers of extreme, heavy, moderate and slight debris flows are 3, 3, 6 and 0 respectively.The calculated results are consistent with the real situation and development trend of studied debris flow area.It proves thereasonability of minimum entropy analysis theory applied in geological disaster risk evaluation.