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 the viscosity of fluid (Habibagahi, 1977; Cho et al., 1999; Delage et al., 2011). However, the changes in hydraulic conductivity with temperature are not only influenced by the changes in water properties, but also by the thermal effect on soil-water interaction at the 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 the 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 the permeability cell to a desired level, a heater and a temperature sensor were 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 a significant effect on the hydraulic conductivity increase of geosynthetic clay liners.