Effects of temperature and analog leachate on hydraulic conductivity of compacted clay

Hydraulic tests are conducted on compacted clay at various temperatures and confining pressures against tap water and analog leachate, using the GDS geoenvironmental permeameter. The hydraulic conductivity increases with the temperature, which is up to 3.5 times higher at 50 ℃ than at 20 ℃. The hydraulic conductivity decreases with the confining pressure from 10-6cm/s at 50kPa to 10-8cm/s at 200kPa. At various temperatures and confining pressures, the hydraulic conductivities against analog leachate are up to 2.8 times higher than those against tap water. The bound water may be thinner and the soil may shrink with the increasing of temperature. As a result, the intrinsic permeability will change with temperature. The ratio of intrinsic permeability at 50 ℃ to at 20 ℃ is between 0.72 and 2.99. Under the experimental conditions, the change in viscosity contributes greatly to the increase in hydraulic conductivity with increasing temperature. The model that only considers water viscosity gives lower predictions at 50kPa against tap water, which will be contrary at a high confining pressure.