库堤联合城市防洪工程体系的防洪能力与防洪风险研究

For the city flood control safety particularity and reservoir flood resource utilization of urgent social needs, aiming at the development trend of domestic and overseas research, Guangxi Nanning City ( the first batch of national key city flood control embankment ) library united city flood control engineering system is taked as the analysis object. On the basis of uncertainty analysis of risk factors, it is researched on capacity of flood control and flood risk operation of flood control engineering system. Considering the influence of climate change and large-scale human activities on flood process and design flood，and the influence of the random combination of regional flood on flood control ability and flood control risk, a risk model of overtopping of flood control engineering system of the city is established. After a joint control of flood is made on flood control engineering system, and solved by Monte Carlo ( Monte-Carlo ) method, the flood risk rate of flood control engineering system of city was calculated and the relationship for flood control capacity and flood control risk is built. According to the flood control risk and allowed risk standard, the actual flood control the ability of flood control engineering system of city can be determined, and be toke as more scientific basis for the city flood risk management and flood resource utilization.

本项目针对城市防洪安全的特殊性和水库洪水资源化利用社会需求的迫切性，瞄准国内外研究的发展趋势，以广西南宁市（全国第一批重点防洪城市）库堤联合城市防洪工程体系为分析对象，在对各种风险因素不确定性分析的基础上，研究库堤联合城市防洪工程体系实际运行中的防洪能力和防洪风险。考虑气候和人类大规模活动对设计洪水的影响以及洪水过程的随机组合对防洪能力和防洪风险的影响，建立城市防洪工程体系的漫坝（堤）风险模型，对防洪工程体系进行洪水联合优化调度，运用蒙特卡罗（Monte-Carlo）方法求解，估算城市防洪工程体系的防洪风险率，建立工程体系防洪能力与防洪风险的关系，根据防洪风险率和允许的风险标准确定城市防洪工程体系的实际防洪能力，为城市防洪风险管理和水库洪水资源化开发利用提供更为科学的基础依据。

本项目以广西南宁市库堤联合城市防洪工程体系为分析对象，在洪水风险因素分析的基础上，研究库堤联合城市防洪工程体系实际运行中的防洪能力和防洪风险。考虑气候变化和人类大规模活动对设计洪水的影响以及洪水过程的随机组合，建立城市防洪工程体系的漫坝（堤）风险模型，对防洪工程体系进行洪水联合调度，运用Monte-Carlo方法求解，估算了城市防洪工程体系的防洪风险率，根据防洪风险率和允许的风险标准确定城市防洪工程体系的实际防洪能力，为城市防洪风险管理和水库洪水资源化开发利用提供较科学的基础依据。研究结果表明，采用季节性一阶自回归模型模拟百色水库、区间入库洪水，模拟的洪水特征参数与实测洪水特征参数相对误差较小，均控制在5%以内，能较好地反映实测样本的统计特性；采用模拟洪水与南宁控制断面各频率设计洪水按一定规则组合，经南宁市防洪工程体系联合调度，南宁市防洪工程体系防洪能力基本上能达到250年一遇洪水标准，大于南宁市原规划设计的200年一遇的防洪标准；当发生200年一遇以下洪水时，百色、老口两库联合调度能满足南宁市设计防洪安全要求，随着洪水的增大，防洪风险相应提高，但风险率在一定范围内并不大，可根据地区发生洪水的标准，适当抬高水库的汛限水位，提高洪水资源化利用率，增加防洪的综合效益。