孔隙-裂隙型基岩含水层DNAPLs（重非水相液体）污染是当前国际上地下水污染控制的热点问题。DNAPLs不仅通过渗透性较高的基岩裂隙快速侵入基岩含水层，形成稳定的污染池，而且在渗透性较弱的基质孔隙中发生累积。随浓度梯度反转（如采取修复措施），累积在基质孔隙中的DNAPLs会缓慢释放到裂隙中，这种跨“介质”、“双向”传质行为对DNAPLs污染池的修复、预测和评估带来极大困难和干扰。本项目拟通过室内实验、多尺度数值模拟和理论推演方法，研究孔隙-裂隙型基岩含水层DNAPLs的跨“介质”、“双向”传质行为机理、探索DNAPLs反常扩散行为与“双向”传质参数的定量化关系与规律、建立孔隙-裂隙双重介质DNAPLs“双向”传质模型、模拟评价DNAPLs“双向”传质行为对地下水环境的影响。研究成果可为基岩含水层DNAPLs污染评估、控制、修复方案的制定提供理论依据和技术支撑。

DNAPLs (Dense non-aqueous liquid) contaminant is a worldwide hot issue in the field of groundwater contaminant control. Not only does DNAPLs rapidly invade bedrock aquifers through the high permeability bedrock fractures, forming a stable pool of contaminants, but also accumulate in the low permeable matrix pores. As the concentration gradient is reversed (i.e., the remediation was used), the DNAPLs accumulated in the matrix pores will slowly release into the fractures. This mass transfer across the different media is a "bidirectional" process, which leads to a great challenge and difficulty in prediction, assessment, and remediation for the DNAPLs pools. The current project through laboratory experiments, multi-scale numerical simulation and theoretical deduction methods intends to study the mechanism of the "bidirectional" mass transfer behavior across the different media, to quantitively explore the laws and the relationship between the anomalous dispersion or migration behavior and the "bidirectional" mass transfer parameters of DNAPLs, to establish a "bidirectional" mass transfer model of the DNAPLs in the porous-fractured rocks, and to numerically evaluate the effect of "bidirectional" mass transfer behavior of DNAPLs on the groundwater environment. This research results would provide a theoretical basis and technical support for assessment, control, and scientific remediation proposal of DNAPLs contaminantin the bedrock aquifer.