Hydraulic Conductivity of Geosynthetic Clay Liners after Freeze-Thaw

Abstract

Hydraulic conductivity tests were performed in large tanks on intact (single panel) and overlapped samples of three geosynthetic clay liners (GCLs) that had been subjected to freeze-thaw cycles. The compressive stress applied to the GCLs (7.6–12.4 kPa) was selected to simulate final cover systems for landfills. Laboratory flexible-wall permeameter tests were also performed. With the exception of one overlapped GCL, all three GCLs withstood three freeze-thaw cycles without a significant change in hydraulic conductivity. An overlapped, geotextile-encased, stitch-bonded GCL did undergo a 1,000-fold increase in hydraulic conductivity after one freeze-thaw cycle, but the overlapped area contained stitches, which are left off the edges of the full-sized material that is deployed in the field. In general, the tests showed that GCLs can withstand at least three freeze-thaw cycles without significant changes in hydraulic conductivity.