裂隙介质中流速及倾斜度对四氯乙烯的运移影响研究

文章选用四氯乙烯（PCE）为代表性重非水相液体（DNAPL），采用透射光法监测PCE在单裂隙介质中的运移过程和形态分布，探究流速及裂隙面倾斜度对PCE运移分布行为的影响。结果表明，单裂隙介质中PCE呈团块状脱离注样针，并在运移过程中呈近椭圆状。地下水流速越大，初始面积Fs越大，近椭圆的PCE离心率e越小；裂隙面倾斜度越大，初始面积Fs越小，近椭圆的PCE离心率e越小。不同流速或倾斜度条件下，入渗稳定后的PCE团块面积与离心率均明显下降。地下水流速及裂隙面倾斜度的增大对于PCE纵向运移具有促进作用，使PCE污染物前端锋面运移速率增大，在相同时间内更快运移到裂隙底部。PCE入渗停止后，流速增大促使污染源区PCE饱和度降低，使饱和度峰值随水流速度增大而减小；倾斜度增大抑制污染源区PCE饱和度降低，使饱和度峰值随倾斜度增大而增大。

Influence of Flow Velocity and Dip Angle on PerchloroethyleneMigration in Fractured Media

Perchloroethylene (PCE) was selected as the representative dense non-aqueous phase liquid (DNAPL) to investigate its migration and distribution characteristics under different flow velocities and dip angles in single fractured media. By using the light transmission method, we could monitor the migration and saturation distribution of PCE dynamically, and therefore the change process of PCE source zone architecture could be characterized. The results showed that PCE separated from the injection needle in the form of lumps, and was nearly elliptical and not continuous with each other in the process of migration. In this paper, Fs refers to the square of the initial pollutant separated from the injection needle. The larger the flow velocity was, the larger Fs was, and the smaller PCE centrifugal rate e was; the larger the dip angle was, the smaller Fs was, and the smaller the centrifugal rate e was. When the infiltration process became stable, the area and centrifugal rate of agglomerated PCE decreased  significantly. The increase of flow velocity and dip angle promoted the vertical migration of PCE, which accelerated the front-end migration rate of PCE and made PCE move to the bottom of the fracture system more quickly. The increase of flow velocity promoted the distribution of PCE, and the peak saturation decreased, while the increase of dip angle suppressed the distribution and made the peak saturation increase during the process.