裂隙地下水中重非水相液体（DNAPL，Dense Non-aqueous phase liquid）污染物，因其不易分解、高残留和微溶解等特性受到人们的高度重视。本项目从溶解过程中DNAPL相体积不断减小引起的“水-DNAPL”界面退化现象出发，拟揭示残留DNAPL溶解速率的非性线变化机制。为此，通过对界面追踪实验的修正，实现定量获取“水-DNAPL”界面面积，分析DNAPL残留量与“水-DNAPL”界面面积的定量关系，利用微观数值模拟，研究“水-DNAPL”界面形态和面积对残留DNAPL溶解速率的相互影响机制，基于实验和数值模拟数据的敏感性分析，探讨多因素对残留DNAPL溶解速率的耦合影响，并建立基于“水-DNAPL”界面退化的粗糙单裂隙残留DNAPL溶解时间预测模型。项目研究成果对裂隙地下水残留DNAPL污染的控制、治理具有重要的理论意义和实用价值。

DNAPL (Dense Non-Aqueous Phase Liquid) contamination in fractured groundwater has attracted much attention because of its hard-decomposition, high residual saturation, and slight solution in groundwater. This study of this project will be started from the interface degradation phenomenon between water and DNAPL in the process of DNAPL volume diminution induced by DNAPL dissolution. Finally, the mechanism of the nonlinear residual DNAPL dissolution rate will be studied in detail. For this purpose, the interfacial area between water and DNAPL will be obtained quantitatively by the revised interfacial portioning tracer test. The quantitative relationship between the residual DNAPL saturation and “water-DNAPL” interfacial area will be analyzed. The interaction effect between the form and area of “water-DNAPL” interface and residual DNAPL dissolution rate will be studied by using micro-simulation method. The mechanism of the nonlinear residual DNAPL dissolution rate will be studied in detail. The coupled influences of factors (aperture distribution, flow velocity, and “water-DNAPL” interfacial area) on the residual DNAPL dissolution rate will be discussed by the sensitivity analysis. After that, the time prediction model of residual DNAPL dissolution based on the “water-DNAPL” interface degradation will be developed in a single rough fracture. The results of this project have the theoretical and practical value for controlling and remediating the residual DNAPL contamination in fractured groundwater.