| A semi-analytical model has been developed for the simulation of solute transport in a fracture network under conditions of steady flow. The model formulates solute transport within fractures using the Laplace transform method. The transport processes incorporated into the model include advection, dispersion, matrix diffusion, adsorption on the fracture and in the matrix, and first order decay. Transfers between fracture elements are governed by conservation of flux as calculated from inlet and outlet concentrations. The solute concentrations in the network are solved in a step-wise manner by using the propagation of source functions through the connected fractures in the down-gradient direction. The inverse Laplace transform is performed using a numerical inversion scheme.;To verify the model, a mass balance was conducted, the solution in a uniform network was compared to an analytical solution using the mean and variance of solute concentration, and matrix diffusion was evaluated by comparison to an independent solution.;To demonstrate the applicability of the model, and to provide some insight into the influence of fracture density and matrix diffusion in granitic rock, flow and transport were simulated in a sample network. (Abstract shortened by UMI.)... |
