基于HEC-RAS的浑太胡同溃堤洪水灾害风险评价

Flood Risk Assessment of Hun-Tai Area Due to Dike Break Based on HEC-RAS

摘要: 洪水灾害是当今世界最为频发的自然灾害之一，而洪水灾害风险评价是防洪减灾的重要支撑。本文建立浑太胡同防洪保护区溃堤洪水灾害风险评价的方法框架，并对研究区因典型溃堤洪水导致的洪灾风险进行评价。首先，通过构建浑太胡同溃堤洪水演进二维数值模型，模拟分析了研究区内溃堤洪水的时空演变过程；其次，以栅格为评价对象，综合考虑研究区的实际情况，建立了溃堤洪水风险评价指标体系，并通过级差最大化合成法组合了指标的层次分析法权重和熵权法权重，得到了各评价指标的组合权重；最后，利用K-Means聚类算法对评价对象综合得分进行了聚类分析，最终得到了研究区发生典型溃堤洪水时的风险情况。结果表明，级差最大化合成法能够对研究区洪水风险进行合理区分，且能避免乘法合成法可能出现的“倍增效应”；当迟拓子与马家堡子组合溃口发生100年一遇的流量过程时，中等和较高洪灾风险区域占研究区总面积的89.64%。

Abstract: Floods are considered as one of the most frequent natural disasters and flood risk assessment is an important support for flood prevention and disaster reduction. This study establishes a methodological framework for evaluating the flood risk of Hun-Tai flood protection zone due to the typical floods. Firstly, by building a two-dimensional numerical model of flooding, the spatial and temporal evolution process of dike-break flood in the study area was simulated and analyzed. Secondly, taking grids as research objects and considering the actual situation, a risk evaluation index system was established, and the subjective weights of the indices calculated by the AHP and the objective weights of the indices calculated by the entropy weight method were combined through the level difference maximization method (LDMM). Finally, the K-Means clustering algorithm was used to perform a cluster analysis on the comprehensive scores of the evaluation objects, and the risk situation of a typical dike-breaking flooding was obtained. The results of the study show that, the LDMM can reasonably evaluate the flood risk, and can avoid the “multiplication effect” that may occur in the multiplicative synthesis method; when a 100-year flow process occurs at the combination of Chituozi and Majiapuzi dike-break, the moderate and higher flood risk areas cover 89.64% of total area.