【作者】 张弛；

【导师】 仵彦卿；

【作者基本信息】 上海交通大学 ， 环境科学， 2014， 硕士

【摘要】 数值模拟方法是研究地下水污染迁移过程的最主要的手段之一，由于含水层的非均质性使得尺度问题又是地下水数值模拟中的前沿课题。本文将渗透系数升尺度和双域质量传输模型这两种升尺度方法引入地下水污染物迁移的数值模拟中，探讨使用升尺度方法以后，非均质含水层中污染物的迁移规律，解决大尺度下地下水溶质迁移时小尺度信息被忽略的问题。本文采用了假想模型和实例相结合的手段。在对假想模型的研究中，运用Markov链地质统计方法生成研究区域的非均质渗透系数场，用MODFLOW程序模拟区域地下水流场，应用MT3DMS程序模拟区域内的溶质迁移。通过对比所得污染物穿透曲线的形态，以及两个穿透曲线的特征量——峰值浓度和峰值到达时间，分析渗透系数升尺度和双域模型这两种升尺度方法对污染物迁移的影响。然后将方法推广到对下辽河平原浑河洪积扇实例的研究中。用参数反演的方法获得实例模型中的渗透系数场。分别考察污染物从河流线源向周边迁移以及从点源向河流迁移的规律。最后探讨含水层的不同非均质性对污染物在实际地下环境中迁移行为的影响。研究结果表明，(1)网格尺寸的大小决定了含水层的非均质性。非均质性对溶质迁移的对流作用影响较小，对弥散作用影响很大，而两者又分别关联污染物迁移的峰值到达时间和峰值浓度。（2）双域模型（过程升尺度方法）计算出的穿透曲线峰值小于对流-弥散模型模拟计算出的穿透曲线的峰值。对流-弥散模型的穿透曲线中始终有一个明显的峰，溶质浓度上升和下降都很快，双域模型的穿透曲线始终在浓度到达峰值以后下降缓慢，形成“拖尾”，因此，在非均质含水层地下水溶质迁移模拟中用双域模型较好；（3）对于含水层非均质性的处理方式，传统的分区赋值方法无法准确地反映实际情况，而采用Kriging插值生成非均质场的方法则能更好地模拟污染物的迁移。更多还原

【Abstract】 Numerical simulation is one of the main methods for groundwater contaminant transportstudying, and the scale problem is a frontier issue in groundwater numerical simulation due toaquifer heterogeneity. This paper introduces two upscaling methods, hydraulic conductivityupscalling and dual-domian mass transfer model to the numerical simulation of groundwatercontaminant transport, and investigates the disciplines of contaminant transport in heterogeneousaquifer with upscaling methods, aiming to solve the problem of missing small-scale informationin groundwater solute transport under larger scales.A combination of hypothetical model and real example is applied. In the study of thehypothetical model, a heterogeneous hydraulic conductivity field is generated using a Markovchain geostatistical technique. Flow field is simulated by MODFLOW and solute transport issimulated by MT3DMS. The effects of hydraulic conductivity upscaling and dual-domain modelon contaminant transport are analyzed by comparing the shapes of the derived breakthroughcurves, peak contaminants and peak arrival times. Then a generalization of the above studyprocedure to the real example of Hunhe River proluvial fan on Lower Liaohe River Plain isexecuted. The hydraulic conductivity field in the example is generated by parametric inversion.The contaminant transports from river linear sources to ambient area and from point sources torivers are studied. Finally, the impact of difference in aquifer heterogeneity on contaminanttransfer in real subsurface conditions is studied.The results show that (1) grid scale determines aquifer heterogeneity. Moreover, heterogeneityhas a small influence on advection and a large influence on dispersion, and these two proceduresare respectively related to peak arrival time and peak concentration of contaminant transport.(2)Peak concentration derived by dual-domain model (progress upscaling) is less than that ofadvection-dispersion model. An obvious peak is always observed in the breakthrough curves ofadvection-dispersion model, and solute concentration rises and drops rapidly. However,“tailing”is observed in the breakthrough curves of dual-domain model, because solute concentration dropsslowly after reaching the peak value. Therefore, it is better to apply dual-domain model togroundwater solute transport simulation in heterogeneous aquifers.(3) To deal with the aquiferheterogeneity, the traditional method of assigning values by blocks cannot accurately reflects thereality, however, the method of generating the heterogenous aquifer by Kriging interpolation canbe used to get a better simulation result of contaminant transfer.更多还原