Effect of Freeze-Thaw Cycles on the Hydraulic Conductivity of a Compacted Clayey Soil from Nazlou Region of Urmia City, Iran, and on a Geosynthetic Clay Liner

The effect of freeze-thaw cycles on the hydraulic conductivity (HC) of compacted clay liner (CCL) and geosynthetic clay liners (GCLs) in water retaining structures and municipal solid waste landfills is a key issue in designing barrier systems in those structures. In this study the effect of freeze-thaw cycles on the hydraulic conductivity of a compacted clayey soil from Nazlou Region of Urmia City and a geosynthetic clay liner; and the effect of effective stress on the hydraulic conductivity change of clayey soil in freeze-thaw cycles was investigated. The flexible-wall triaxial hydraulic conductivity apparatus was used to measure the HC of specimens subjected to freeze-thaw. During the freezing process ice lenses grow in soil sample and when the ice lenses melt, a network of cracks is left and thus the HC increases. Increasing the effective stress reduces the increased hydraulic conductivity due to freeze-thaw. The results show that on the contrary to compacted clayey soil, the application of freeze-thaw cycles do not significantly affect the HC of GCL even when GCL sample is subjected to extreme climatic conditions during which it continues to exhibit good performance as a hydraulic barrier

Keywords:

Freeze-thaw cycles , Hydraulic conductivity , Compacted clay , Geosynthetic clay liners