Experimental Investigation on the Effects of Temperature on Physical Properties of Sandy Soils

There has been a growing recognition around the world to use geothermal energy. Rejecting or harvesting to and from the ground results in temperature changes of the soil. The geotechnical properties of sand and clay vary under different environmental temperature. Temperature increment induces volumetric changes and also alters fluid properties (e.g., groundwater) in the soil skeleton. These variations might increase or decrease the soil strength and soil intrinsic permeability. Although several researches have been performed to study the effects of temperature on sand and clay soils; the exact thermo-physical behavior of soils need to be investigated. This paper presents the effect of temperature variation on sand behavior (intrinsic permeability and void ratio). The modified triaxial apparatus with automated heating control system was designed to control the temperature of the cell and the specimen in the range of 5 to 90°C. The device can be used to do mechanical consolidation and shear strength tests at different temperatures to compare the stress-strain behavior of the soil under temperatures. Triaxial permeameter cell is also used to study the variation of soil hydraulic conductivity and soil intrinsic permeability with temperature. Results obtained from the experimental tests confirm that soil hydraulic conductivity increases with temperature. However, interestingly soil intrinsic permeability shows reverse behavior with temperature. This reduction in soil intrinsic permeability with temperature is a result of changes in void ratio of the soil skeleton due to thermal loading.