Electrical Resistivity of Soils Due to Cyclic Freezing and Thawing

The electrical resistivity of soil is affected by various factors, such as the electrical resistivity of pore fluids, the porosity, the constituent of soil particles, the saturation, the orientation and shape of soil particles, and the pore structure. The purpose of this study is to determine the changes in the electrical resistivity of sand-silt mixtures during freeze-thaw cycles. To measure the electrical resistance over freeze-thaw cycles, a nylon cell was designed and an electrode was attached to each of the four side walls of the cell. Two specimens, with different degrees of saturation (40% and 60%), were prepared using sand-silt mixtures. The measured electrical resistances were then transformed into electrical resistivities. The results show that, in both specimens, the electrical resistance increases during the repeated cycles, and hysteresis behavior appears immediately after the beginning of thawing. In addition, the electrical resistivities of both samples are less during thawing than during freezing from 0°C to -3°C. While the electrical resistivity increases rapidly at 0°C during freezing, the electrical resistivity at 0°C decreases relatively gradually during thawing. For the specimens with a saturation of 40%, the electrical resistivity during thawing was greater than the electrical resistivity during freezing at ordinary temperatures. This study demonstrates that electrical resistivity surveys may be useful for analyzing the structure and behavior of soils during freezing-thawing cycles.