边界层对粗糙单裂隙溶质运移影响试验

为探究非费克(non-Fickian)运移表现出的峰值提前到达和拖尾等现象，开展了粗糙单裂隙溶质运移试验，总结了粗糙单裂隙中溶质运移特征及运移机理，结合边界层理论对峰值提前到达和拖尾现象进行了分析和解释。结果表明：峰值时间和拖尾时间与边界层厚度之间存在较好的线性相关关系；边界层对裂隙介质溶质运移有较为显著影响，即水流速度越小，边界层厚度越大，滞留在边界层内部的溶质越多，溶质获取率越低；粗糙单裂隙中溶质穿透曲线的峰值提前和拖尾现象是由裂隙中心处以惯性力主导的主流区和裂隙壁面以黏性力主导的边界层区共同作用造成的，其中峰值时间主要由主流区的对流因素控制，而边界层区域的存在对拖尾时间影响较大。

Experimental study of the effect of boundary layer on the solute transport in a rough single fracture

To explore the phenomena of early peak arrival and trailing of non-Fickian migration, the solute migration experiment of a rough single fracture is carried out, the solute migration characteristics and migration mechanism in the rough single fracture are summarized, and the phenomena of early peak arrival and trailing are analyzed and explained in combination with the boundary layer theory. The results show that there is a good linear correlation between the peak arrival time, the trailing time and the thickness of the boundary layer; The boundary layer has a significant effect on the solute transport in fractured media, that is, the smaller the flow velocity is, the greater the thickness of the boundary layer is, the more solutes remain in the boundary layer, and the lower the solute acquisition rate is; the peak advance and trailing of solute penetration curve in the rough single fracture are caused by the joint action of the main flow area dominated by the inertial force in the fracture center and the boundary layer area dominated by the viscous force on the fracture wall. Among them, the peak arrival time is mainly controlled by the convection factor in the main flow area and the existence of the boundary layer area has a great influence on the trailing time.