Experimental and numerical modeling of solute transport through fractured sedimentary rock mass

This paper presents the experimental breakthrough curves for conservative and non-conservative tracers through a fractured porous sandstone rock mass. An experimental model for the fractured rock mass was developed in the laboratory. This model consisted of 4 m long sandstone slabs, placed face to face parallel to each other. A small space of 4 mm wide was created between sandstone slabs, through which the water was allowed to flow. Sodium chloride and sodium fluoride solutes were used as conservative and non-conservative tracers through experiments. A numerical model was also developed for the solution of advective–dispersive transport equation including the equilibrium sorption and the first order degradation constant for reactive solute transport. The developed numerical model was used to simulate the observed experimental breakthrough curves through the fractured rock mass. The observation of the breakthrough curves indicates that the mass of solute reduces in the fracture due to sorption and diffusion of solute within the rock mass. An attempt has also been made to estimate the transport parameters such as effective diffusion, dispersion coefficients and sorption coefficients. © 2016 Indian Society for Hydraulics.