Effects of Temperature and Dry Density on Hydraulic Conductivity of Silty Clay under Infiltration of Low-Temperature Water

Abstract

Volumes of low-temperature water present in large reservoirs have increased considerably worldwide during the past decades. One of the most important soil physical properties affected by low-temperature water use is soil saturated hydraulic conductivity. Using a custom-made permeability testing device, we studied the permeability of a silty clay and analyzed the combined influence of bulk density and water temperature on permeability. The results show that when the dry bulk density of the silty clay sample increases from 1.4 to 1.6 g/cm3, the hydraulic conductivity decreases exponentially from 10−4 to 10−5cm/s (at 10, 15, 20 and 25 °C). When the water temperature is 25 °C and the dry bulk density is either 1.4, 1.5 or 1.6 g/cm3, the hydraulic conductivity is more or less three times as high as that when the temperature is 10 °C. When the dry bulk density is 1.4 g/cm3 and the water temperature increases from 10 to 25 °C, the dimensionless permeability factor (k′/k) is close to unity. The same parameter (k′/k) becomes considerably larger than 1 when the dry bulk density are, respectively, 1.5 and 1.6 g/cm3.