Abstract: To analyze the anti-seepage performance of geosynthetic clay liner (GCL) after long-term freeze-thaw cycles， the 6-hour freezing and 6-hour thawing cycle tests on GCL material were carried out. The permeability coefficient and free swelling ratio of GCL after different freeze-thaw cycles were studied. The results show that the frost heave of GCL can reach a stable state within 4h， and when frozen again， differential frost heave can occur in the GCL sample after freeze-thaw cycles. When the number of freeze-thaw cycles is low (≤30times)， the permeability coefficient of GCL decreases with increase of the number of freeze-thaw cycles， and the permeability coefficient is between 10^-11m/s and 10^-10m/s. As the number of freeze-thaw cycles increases， the free swelling ratio of bentonite in GCL increases first， then decreases and finally reaches a steady value.

Key words: GCL(geosynthetic clay liner), freeze-thaw cycle, hydraulic permeability, bentonite, free swelling ratio