基于GMS的水力控制措施下污染物迁移预测分析

Prediction and Analysis of Pollutant Migration Under Hydraulic Control Measures Based on GMS

为解决某项目在具有局部水力控制措施复杂条件下污染迁移特征分析,采用GMS数值模拟预测分析持续渗漏污染情景对浅层第四系孔隙水的地下水环境影响特征。结果表明:在有局部人工水力控制措施的情况下,污染晕沿主流场方向扩展最快,迁移范围最大,验证了污染迁移受水力控制为主,受局部导排地下水的措施影响较明显,而向上游及侧向扩展相较于主轴方向并不显著;污染物在渗透性相对较差、孔隙度相对较低的隔水层发生较明显的阻隔作用,即浅层含水层中污染物垂向浓度梯度大,随着深度增加而浓度梯度显著降低;由于第一承压含水层渗透性明显高于潜水含水层,污染晕虽然时间上滞后进入,但是进入后的扩展速度相对较快,对流作用对污染晕的分布起主导作用,导致了该层“超标污染区域”范围小,而“影响区域”范围大的现象。

In order to solve the prediction and evaluation of the impact of the continuous leakage pollution to the groundwater environment of Shallow Quaternary pore water under hydraulic control measures,a numerical simulation prediction and analysis work based on GMS(Groundwater Modeling System)was carried out in this study.The results are as follows:In the case of local artificial hydraulic control measures,the pollution halo along the main flow direction expands the fastest.It is confirmed that the pollution migration is mainly controlled by hydraulic power and influenced by the measures of local drainage of groundwater,while the upstream and lateral expansion is not significant compared with the main axis.Pollutants in aquicludes with poor permeability and low porosity are obviously blocked,which means the vertical concentration gradient of pollutants in the shallow aquifers is large,and the concentration gradient decreases significantly with the increase of depth.The permeability of the first confined aquifer is significantly higher than phreatic aquifer.Although the pollution halo enters confined aquifer later,the expansion speed is relatively faster.Convection plays a significant leading role in the distribution of pollution halo,resulting in the phenomenon that pollution area is small and influence area is large.