Mobile-immobile model of solute transport through porous and fractured media

摘要

Investigation of analytical models of solute transport is a key aspect in parameter identification at both the micro and field scales. The advection-dispersion equation (ADE) is commonly used to describe the movement of solute transport in porous media. However, increasing evidence indicates that the ADE model is problematic in describing transport in heterogeneous, fractured or even "homogeneous" media. In this paper, an alternative mobile-immobile (MIM) model is employed for describing solute transport in both porous and fractured media. Tracer experiments in porous and fractured media were carried out. The breakthrough curves (BTCs) were fitted by both the ADE and MIM models and results show that the MIM model does better than ADE in both porous and fractured media, especially in describing the peaks and long tails of the BTCs. The MIM model, which is physically sound, can explain the BTCs better in a rough-walled fracture than in a smooth-walled fracture.