区域地下水污染物运移风险特征仿真研究

Simulation Study on Risk Characteristics of Regional Groundwater Pollutant Transport

为减少地下水污染物运移风险,合理制定地下水污染应急预案,提出区域地下水污染物运移风险特征仿真研究。分析污染物在地下的循环过程,针对扩散迁移方式,获取污染物浓度随时间变化的表达式;选取区域化变量,构建变异函数,将变化梯度和幅度作为变异指标,探究污染物迁移空间存在的随机性与机构性;根据达西定律与质量守恒理论,将含水量作为唯一自变量,分别建立包气带与含水层的水流模型与污染物迁移模型,实现污染物运移风险评价。仿真结果发现,在砂石含量高的土壤中,污染物运移速度更快,转移污染风险较高;在黏土含量较高的土壤中,污染物容易吸附在黏土表层,局部污染风险较高。

This paper proposes a simulation study on the risk characteristics of regional groundwater pollutant transport in order to reduce the risk of groundwater pollutant transport. The circulation process of pollutants underground was investigated in detail. The expression to obtain the variation of pollutant concentration with time was obtained according to the diffusion and migration mode. Regionalized variables were used to establish variogram. The variation gradient and amplitude were utilized as variation indicators to explore the randomness and mechanism of pollutant migration space. Based on Darcy’s law and mass conservation theory, taking water content as the only independent variable, the flow model and pollutant migration model of the vadose zone and aquifer were established respectively to realize the migration risk of pollutants. The simulation results show that in the soil with high sand and gravel content, the pollutants migrate faster and the risk of transferring pollution is higher. In the soil with high clay content, pollutants are easily adsorbed on the clay surface, resulting in a high local pollution risk.