LNAPL污染物的时移高密度电阻率法数值模拟及应用研究  

Numerical Simulation and Application of Time-Lapse High-DensityResistivity Imaging Method in Detecting LNAPL Pollutants

作　　者：吴奇 苏志强 徐量 韩润 倪炯 周欣 平利姣 Wu Qi;Su Zhiqiang;Xu Liang;Han Run;Ni Jiong;Zhou Xin;Ping Lijiao(Marine Geological Survey of Jiangsu Province;The Sixth Geological Brigade of Jiangsu Geological Bureau;Huai′an Water Conservancy Survey and Design Institute Co.,Ltd.;School of Earth Sciences and Engineering,Hohai University)

机构地区：[1]江苏省海洋地质调查院,南京市210001 [2]江苏省地质局第六地质大队,江苏连云港222000 [3]淮安市水利勘测设计研究院有限公司,江苏淮安223001 [4]河海大学地球科学与工程学院,南京市211100

出　　处：《勘察科学技术》2025年第2期76-86,共11页Site Investigation Science and Technology

基　　金：国家重点研发计划资助(2021YFC3000103)。

摘　　要：轻非水相液体(LNAPL)污染危及人的健康和生态环境,如何准确地探测LNAPL污染区域是当今社会的难题之一。该文利用有限元法的COMSOL Multiphysics软件,构建了不同时刻以及水位变化情况下LNAPL污染物的扩散模型,对扩散过程中地下介质电性特征进行数值模拟。数值模拟结果表明,时移高密度电阻率法能够有效凸显地下介质的电性变化,对LNAPL污染物在地下的运移有更好的探测效果;随着LNAPL污染物的扩散,异常区域的视电阻率差逐渐减小,而异常范围逐渐扩大;在水位上下波动时,时移高密度电阻率法对水位的变动和LNAPL污染物的扩散均有反映。在水位下降后,LNAPL污染物随水位下降导致土壤电阻率增大;在水位上升后,仍有部分LNAPL污染物并未随水位抬升而残余在地下介质中导致电阻率增大。在3%环境噪声的影响下,随着LNAPL污染物的扩散,高阻异常区域的视电阻率差逐渐减小,异常范围扩大这一特征仍能有效反映。进一步地,结合数值模拟成果进行室内实验,并对南京六合某化工厂区LNAPL污染的扩散范围进行探测推断。Light non-aqueous phase liquid(LNAPL)pollutants pose significant risks to human health and the ecological environment.Accurately detecting LNAPL-contaminated areas remains a critical challenge in today′s society.This paper uses the finite element-based COMSOL Multiphysics software to construct a diffusion model of LNAPL pollutants under different timeframes and changing water levels.The electrical characteristics of the subsurface medium during the diffusion process are numerically simulated.Numerical simulation results show that the time-lapse high-density resistivity imaging(HDRI)method more effectively highlights electrical changes in the subsurface medium and provides improved detection of LNAPL migration.As LNAPL pollutants spread,the apparent resistivity difference in the abnormal region decreases gradually,while the abnormal area gradually expands.When the water level fluctuates up and down,the time-lapse HDRI method responds to both water level fluctuations and LNAPL diffusion.Following a drop in water level,LNAPL pollutants cause an increase in the soil resistivity.Conversely,when the water level rises,some LNAPL pollutants remain trapped in the subsurface rather than ascending with the water,resulting in sustained resistivity anomalies.Under 3%environmental noise conditions,with the diffusion of LNAPL contaminants, the apparent resistivity difference in the high-resistance anomaly area gradually decreases, and the method effectively captures the trend of decreasing resistivity contrast and expanding anomalous regions. Furthermore, indoor experiments are conducted to validate the numerical simulation results. The method is also applied to an LNAPL-contaminated site at a chemical plant in Liuhe, Nanjing, to delineate the extent of pollutants.

关 键 词：时移高密度电阻率法 轻非水相液体 污染物 数值模拟 

分 类 号：X53[环境科学与工程—环境工程]