饱和砂土中DNAPL污染物迁移过程及数值模拟  

Transport processes and numerical simulation of DNAPL contaminants in saturated sandy soils

作　　者：肖鹏[1] 刘汉乐[1] XIAO Peng;LIU Han-le(Collaborative Innovation Center for Water Contaminant Control and Water Safety in Karst Area,Guangxi Key Laboratory of Environmental Contaminant Control Theory and Technology,Guilin University of Technology,Guilin 541004,China)

机构地区：[1]桂林理工大学,广西环境污染控制理论与技术重点实验室,岩溶地区水污染控制与用水安全保障协同创新中心,广西桂林541004

出　　处：《中国环境科学》2024年第1期386-395,共10页China Environmental Science

基　　金：国家自然科学基金资助项目(42277192);第三期广西高等学校千名中青年骨干教师培育计划项目。

摘　　要：基于物理砂箱实验所获参数,运用数值模拟Petrasim程序模拟DNAPL在饱和多孔介质中的迁移过程,探究DNAPL在重力和毛细力共同作用下的迁移行为与迁移路径中污染物的分布特征.研究表明:⑴DNAPL污染物入渗前期主要受重力影响呈“液滴”状垂向扩散,在垂向扩散至底部不透水层后,DNAPL在毛细力驱动下开始横向再分布扩散,最后在底部形成长期的“池状”污染源区;⑵通过对比验证数值模拟结果和实验结果,其垂向扩散相对误差范围为-2.96%~5.95%.横向扩散的相对误差范围为0.04%~23.41%.平面污染面积相对误差范围为0.03%~19.39%.表征横向扩散、垂向扩散与污染面积模拟值与实验值差异性的拟合决定系数R2分别为0.8827、0.9919、0.9832,模拟结果与实验值接近,模拟效果良好.结果说明了数值模拟Petrasim程序预测饱和多孔介质中DNAPL迁移行为和污染分布范围的可靠性与准确性.在野外环境中DNAPL泄露污染的污染范围评估与迁移行为预测方面具有广阔的应用前景.In this paper,based on the parameters obtained from the physical sandbox experiment,the numerical simulation Petrasim program was utilized to simulate the migration process of DNAPL in saturated porous media,which has certain research significance in exploring the migration behavior of DNAPL under the combined action of gravity and capillary force and the contaminants distribution characteristics in the migration paths.The numerical results and experimental data showed that:(1)in the early stage of infiltration,DNAPL was mainly affected by gravity and showed"droplet"vertical diffusion.After vertical diffusion to the bottom impervious layer,DNAPL began to redistribute and spread laterally driven by capillary force,and finally forms a long-term"pool"contaminant source area at the bottom of sandbox;(2)By comparing the simulation results with the experimental data,the relative error range of the vertical diffusion was-2.96%~5.95%.The relative error range of horizontal diffusion was 0.04%~23.41%,and the relative error range of plane contamination area was 0.03%~19.39%.The fitting determination coefficients R2 which characterize the differences between the simulated values and the experimental data of horizontal diffusion,vertical diffusion and contaminant area were 0.8827,0.9919 and 0.9832,respectively.The simulation results were close to the experimental data,which is satisfactory.The reliability and accuracy of numerical simulation Petrasim program in predicting DNAPL migration behavior and contaminant distribution in saturated porous media were investigated in this study.Indicating that the assessment of DNAPL leakage range and the prediction of DNAPL migration behavior have broad application prospects in the field environment.

关 键 词：重非水相液体 污染物分布 数值模拟 饱和砂土 

分 类 号：X501[环境科学与工程—环境工程]