Effect of temperature on the hydraulic conductivity of compacted clayey soil and geosynthetic clay liner (GCL)

In most studies, the increase in hydraulic conductivity with temperature has been considered due to the decrease in viscosity of fluid (Habibagahi, 1977; Cho et al., 1999; Delage et al., 2011). However, the changes of hydraulic conductivity with temperature are not only influenced by the changes of water properties, but also by thermal effect on soil-water interaction at microstructure level (Towhata et al., 1993; Romero et al., 2001; Villar and Lloret, 2004). In the present study, results of temperature effects on the hydraulic conductivity of compacted clay from Nazlou region of Urmia City (Iran), and geosynthetic clay liner (GCL) are presented. In this research experiments were conducted by flexible-wall triaxial permeability apparatus. In order to increase the temperature of permeability cell to a desired level, a heater and a temperature sensor was used. Results showed that by increasing the temperature, the viscosity of fluid decreases, the soil pore size increases, cross section of effective flow increases and hence, the soil hydraulic conductivity increases. Increasing the effective stress causes the rate of increase in soil permeability due to temperature to decrease. Results showed that temperature increase does not have significant effect on the hydraulic conductivity increase of geosynthetic clay liners.