Factors affecting multicomponent GCL-geomembrane interface transmissivity for landfills

A series of laboratory tests were conducted to investigate the interface transmissivity, θ, between a 1.5 mm thick high-density polyethylene geomembrane (GMB) and a multicomponent geosynthetic clay liner (GCL) when permeated with a simulated municipal solid waste landfill leachate under a range of applied stresses (10–150 kPa). The effect of three different prehydration fluids, a 4 mm diameter central coating defect, coating defect position, and the effect of coating orientation of the GCL were investigated. It was found that at an applied stress of less than 70 kPa, the effect of these factors on θ was largely masked by the variability in the initial interface contact condition between the GMB and GCL. At 100–150 kPa, the effects of initial variability were largely eliminated, but there was no notable effect of other factors for multicomponent GCLs on interface transmissivity.