Ningxia Autonomous Region is a key zone of"the Belt and Road" strategy implementation in China. Geologic hazards such as collapse,landslide and debris flow,etc. are well-developed in the re-gion,extremely in mountain areas of southern Ningxia,located in the Loess Plateau region. The hazards seriously restrict the sustainable economic development in the region. Based on analysis of the investiga-ted data of geologic hazards in the region,this paper discussed the development characteristics and dis-tribution rules of debris flows in the mountain areas of southern Ningxia. Hazard zonation evaluating sys-tem for debris flow was constructed,considering 7 indexes including point density,average gradient,val-ley relative relief,erosion degree,basin area,gully-bed gradient and precipitation. In order to guarantee rationality of the index weight,the optimal combination weighting method was used in the weight deter-mination. Then,evaluation indexes were extracted,classified,quantized and superposition calculated ac-cording to slope units by application of comprehensive evaluation method based on GIS. Based on the calculated results,the danger level was divided into high risk-degree,middle risk-degree and low risk-degree using the catastrophe point method. The evaluation results are consistent with the field investiga-tion results. This work provides a theoretical basis for risk assessment of debris flow hazards,disaster pre-vention and reduction in engineering constructions in the region.%宁夏回族自治区是中国实施"一带一路"战略的重要枢纽地带,由于地处黄土高原地区,崩、滑、流等地质灾害十分发育,以宁夏南部山区尤为突出,严重制约该地区的经济可持续发展.为了对泥石流灾害危险性进行量化评价,基于宁南山区地质灾害详细调查资料的分析,阐述了宁南山区泥石流发育特征和分布规律,构建了包括泥石流点密度、平均坡度、流域相对高差、侵蚀程度、流域面积、沟床比降、降雨等7个指标的泥石流灾害危险程度评价指标体系.采用最优组合赋权法确定各指标权重值,并基于GIS对各指标进行提取和分级量化,应用综合评判法按斜坡单元进行叠加计算.进而,采用突变点法将泥石流危险程度分为低危险、中危险和高危险3个等级,取得了较好的评价效果,与实地调查结果相符,可为宁南山区泥石流灾害风险评估及工程建设中防灾减灾提供可靠理论依据.
展开▼
