Experimental investigation and numerical simulation of contaminant migration in the compacted clay containing artificial fractures

摘要

Many researchers have discussed contaminant migration in clay liners, but study of compacted clay with vertical fractures is rare. In this paper, an experimental model was developed to assess how a vertical fracture influences contaminant migration in a clay layer. Experimental results were compared with numerical simulation data. Dispersion parameters were calibrated according to measured and calculated concentrations from observation holes. Three factors, affecting the intact clay, different depths of landfill leachate, and fracture aperture, have been discussed using the calibrated parameters. Results show that contaminant migration in fractured clay is faster than in intact clay and the break-through time for the tracer was shorter than that in intact clay. The migration rate of the tracer in fractured clay first decreased and then increased with increasing landfill leachate depth. Furthermore, larger fracture apertures accelerated the rate of contaminant migration.