A study for determining the hydraulic conductivity of geosynthetic clay liners in the laboratory

This study was prepared to show how to perform the hydraulic conductivity test on geosynthetic clay liners (GCLs) and how to evaluate the results. In the content of this study, four types of GCLs were subjected to hydraulic conductivity tests using deionized water and tap water. The tests lasted six months and the final hydraulic conductivities of GCLs were measured within the range of 7.1 × 10 -10 - 1.4 × 10 -9 cm/s. To terminate the tests, it was checked to see whether hydraulic stability was achieved or not throughout the test duration. To do this, hydraulic conductivity ratio was defined and it was accepted that the stability was assured when this ratio was reduced below 1.5. Besides, it was found that the effect of permeant water and the GCL types on the hydraulic conductivity were limited. The results of this study were also compared with the hydraulic conductivities that were reported in the literature as a function of effective stress. It is concluded that the findings of this study are in agreement with those in the literature.