Effect of Poor Distribution of Needle Punched Fibres on Gas Permeability of GCLs

In recent years, design engineers and environmental agencies have shown a growing interest in the use of geosynthetic clay liners (GCLs) as an alternative to soil barriers as part of cover systems. As part of the evaluation process, GCL gas flow properties are considered to be as important as the hydraulic properties. Recent studies have shown that the gas permeability of GCLs varies largely with the change of gravimetric moisture content. This paper shows that a poor distribution of needle punched fibres in the GCL can affect its gas permeability and highlight the importance of a good quality control of the manufacturing process.