河北省泥石流灾害易发性云模型评价方法:以邢台赵沟村泥石流为例

Development Law of Debris Flow Disaster and the Evaluation Method of Its Susceptibility:Take Mudslide in Zhaogou Village,Xingtai as an Example

建立定量化的泥石流易发性评价方法对于泥石流灾害的防治工作具有重要意义。通过对河北省130处泥石流沟的详细勘查和数据整理,分析总结了河北省泥石流的区域性特征。在此基础上,选取评价因子,引入随机森林分类方法确定评价因子的权重,采用高斯正向云模型建立了评价因子与泥石流易发性等级的定量关系,最后,通过工程实例证明新方法的合理性。研究表明:河北省西部、东北部泥石流灾害点分别被600 mm和700 mm年降雨量等值线包围,北部地区泥石流灾害点则多位于年降雨量等值线400 mm与500 mm之间。河北省泥石流形成关键因子为降雨强度、汇水面积、沿沟松散物储量、沟岸山坡坡度、流域相对高差和沟谷比降等;河北省泥石流类型主要为中小型沟谷暴雨-水石流;工程实例分析表明基于随机森林赋权的泥石流易发性云模型评价方法评价结果与实际情况相符。

The establishment of a quantitative mudslide susceptibility evaluation method is of great significance for the prevention and control of mudslide disasters.Through the detailed survey and data compilation of 130 mudslide ditches in Hebei Province,the regional characteristics of mudslides in Hebei Province were analyzed and summarized.On this basis,evaluation factors were selected,the weights of evaluation factors were determined by introducing random forest classification method,the quantitative relationship between evaluation factors and mudslide susceptibility level was established by using Gaussian forward cloud model,and finally,the rationality of the new method was proved by engineering examples.The study shows that the mudflow hazard sites in western and northeastern Hebei Province are surrounded by 600 mm and 700 mm annual rainfall contours,respectively,while the mudflow hazard sites in northern areas are mostly located between 400 mm and 500 mm annual rainfall contours.The key factors of debris flow formation in Hebei Province are rainfall intensity,catchment area,loose material storage along the gully,slope of the gully bank,relative height difference of the watershed and specific drop of the gully.The type of debris flow in Hebei Province is mainly small and medium-sized gully storm-water and rock flow.The engineering example analysis shows that the evaluation results of the cloud model evaluation method of debris flow susceptibility based on random forest empowerment are consistent with the actual situation.