地下水DNAPLs污染多相流的随机模拟及其不确定性分析

Stochastic simulation and uncertainty analysis of multi-phase flow of groundwater polluted by DNAPLs

水文地质参数本身存在不确定性,为分析水文地质参数不确定性对地下水DNAPLs污染多相流数值模拟模型输出结果的影响,本文针对假想算例展开研究,首先建立了研究区地下水DNAPLs污染多相流数值模拟模型;然后,运用灵敏度分析法筛选对模型输出结果影响较大的参数作为随机变量;为减少反复调用多相流模拟模型产生的计算负荷,运用克里格方法建立多相流模拟模型的替代模型,利用替代模型完成蒙特卡洛随机模拟;最后,对随机模拟的结果进行统计分析并完成地下水污染风险评价.结果表明,利用污染物浓度分布函数可以估算单井遭受污染的风险;利用地下水污染风险图可以对全区地下水遭受不同程度污染的风险大小进行分区,为地下水污染防治提供更加科学、丰富的参考依据.

Hydrogeological parameters were uncertain.In order to analyze the influence of hydrogeological parameter uncertainty on the numerical model of multi-phase flow of groundwater polluted by DNAPLs,aimed at making a research on hypothetical example,this paper firstly established a numerical simulation model of multi-phase flow of groundwater polluted by DNAPLs in research area.Then,the sensitivity analysis method was used to select the largest parameters that affect the output of the model as stochastic variables.In order to reduce the computation burden caused by the repeated call of simulation model,the Kriging method was used to construct a surrogate modle to finish the stochastic Monte Carlo simulation.Finally,the stochastic simulation results were analyzed statistically and the pollution risk assessment was completed.The results showed that the risk of pollution of single well can be estimated by using the pollutant concentration distribution function.The whole area can be divided into different risk areas under different pollution levels,which can provide a richer and more scientific reference to groundwater pollution prevention and control.