Properties and variation of electrical resistivity due to temperature change

The objective of this study is to determine the variation in the electrical resistivity of unsaturated soils due to temperature change. A nylon cell is designed for the installation of electrodes and the preparation of specimens, which are sand-silt mixtures with different degrees of saturation. To reflect the effect of the geometry of the electrodes, a calibration is performed for the conversion of the electrical resistance measured in three specimens to electrical resistivity. The electrical resistances of the specimens are continuously monitored as their temperature changes from 20°C to -10°C. The experimental results reveal that a higher degree of saturation results in a lower electrical resistivity at 20°C. The electrical resistivity increases gradually with a decrease in temperature and sharply increases near the freezing point for all the unsaturated specimens. For frozen soils, the electrical resistivity slowly increases as the temperature decreases. This study yields fundamental information regarding the electrical resistivity of unsaturated frozen soils and the practical application of resistivity for frozen-ground characterization.