基于蒙特卡罗法的土石坝洪水漫顶风险率计算及其敏感性分析

为了减少土石坝因洪水漫顶造成溃坝所带来的损失,详细介绍了计算土石坝洪水漫顶风险率的蒙特卡罗法模型,分析了影响土石坝洪水漫顶的主要因素为洪水、风浪、水库运行调度方式和水库特性。针对这些因素进行洪水漫顶风险率的敏感性分析,并以南方某土石坝为例进行了实例研究。结果表明:洪峰流量均值和变差系数以及最大风速的均值对土石坝洪水漫顶风险率的影响较大,洪峰流量的偏态系数和风速的均方差的影响较小;水库自身特性及洪水到来前的水库初始水位的影响也比较大。该实例计算得到的洪水漫顶风险率经与相关工程实例分析计算成果比较,表明采用蒙特卡罗法计算洪水漫顶风险率是可信的。

Calculation and Sensitivity Analysis of Risk Probability of Earth-rock Dam Overtopping Caused by Floods Based on Monte-Carlo Method

The detailed process to calculate risk probability of earth-rock dam overtopping caused by floods based on Monte-Carlo Method was presented in this paper.Factors affecting the risk probability,inclusive of flood,wind wave,reservoir scheduling and reservoir features were deeply analyzed and sensitivity analysis for these factors was conducted.An earth-rock dam in south China was taken for example.Results reveal that the mean value of peak flow,the coefficient of variation,as well as the mean value of maximum wind speed have large impact on the risk probability;whereas the coefficient of skewness and the mean wind speed variance have little effect.Besides,the reservoir characteristics and the initial water level before flood also have considerable influence on the risk probabil-ity.By comparing the calculated results with engineering analysis results,we conclude that it’s reliable to calculate the risk probability of earth-rock dam overtopping by using Monte-Carlo method.