淮北市地下水流数值模拟及水文地质参数不确定性分析

Numerical simulation of groundwater flow near Huaibei and uncertainty analysis of the hydrogeological parameters

淮北市用水主要取自地下水,开采量大,开采布局不合理已引发一系列环境问题。建立可靠的地下水流数值模拟模型,对于定量评价淮北市地下水资源、优化开采布局具有重要的现实意义,而目前针对淮北市进行的地下水数值模拟研究尚不多见。在分析安徽淮北市水文地质条件的基础上,建立了研究区水文地质概念模型和地下水流数学模型。并应用灵敏度分析法及蒙特卡罗法对模拟层的水文地质参数进行不确定性分析。灵敏度分析结果表明,含水层的给水度或单位释水系数及弱透水层的垂向渗透系数对模拟结果的影响最大,获得了各层灵敏度最大的参数分区,可为今后野外勘察试验提供参考。蒙特卡罗法结果直观地反映出各层敏感性分布,进一步证明了确定性模型的合理性。

Water used in the city of Huaibei is mainly from groundwater which has caused a series of environmental problems with the increasing quantity of groundwater exploitation and the unreasonable distribution of pumping wells. It is of practical significance to build an accurate and reliable groundwater model to evaluate groundwater resources and optimize the well distribution near Huaibei,but little attention is paid to the numerical simulation of groundwater flow in the study area. Based on analysis of the hydrogeological conditions near Huaibei, hydrogeological conceptual model and mathematical model of groundwater flow in this area are established. The numerical model is established by using the GMS software packages. The uncertainties of hydrogeological parameters of different layers are analyzed with the sensitivity analysis method and the Monte-Carlo method. The results with the sensitivity analysis method indicate that the specific yield or specific storativity of the aquifers have remarkable effect on the simulation results and the simulation results are relatively sensitive to the vertical hydraulic conductivity of the aquitard. With this method,the zones with maximal sensitivity from each layer are obtained,providing a scientific basis for the future field reconnaissance and test. The results with the Monte-Carlo method can reflect intuitively the sensitivity distribution of each layer. The results prove the rationality of the deterministic model.