Gas advective flux of partially saturated geosynthetic clay liners

A series of gas permeability tests were performed on partially saturated needle punched and stitch bonded geosynthetic clay liners (GCLs) with nitrogen (N₂) as the gas permeant fluid. The results of this investigation highlighted the influence of the water content and the hydration process on the gas flow kinetics through geosynthetic clay liners. For the GCLs and conditions examined, it was found that the intrinsic permeability and permittivity decreased as the moisture content increased. The presence of a surcharge seemed to reduce gas flow through GCLs at moisture contents higher than around 50%, however, below this value the surcharge had no effect. Furthermore, it was found that the stitch bonded GCL led to higher gas permeability than the needle-punched material.