A Capillary Bundle Model for the Electrical Conductivity of Saturated Frozen Porous Media

Liquid water in frozen porous media provides the path for moisture and solute migration, which is one of the essential problems to study thaw-weakening and frost-heave in freezing region engineering. Determining and monitoring liquid water saturation and permeability in saturated frozen porous media are therefore critical issues in cold regions. To this end, geophysical methods are tools of choice given their non-invasive nature. Electrical conductivity as a physical property is related to both the bulk characteristics of saturated porous medium submitted to frozen temperatures, like porosity as well as liquid water content, and surface properties, such as the solid surface-liquid water and bulk ice-liquid water interfaces. In this study, we upscale a microstructural procedure of liquid water-saturated frozen soils to predict the electrical conductivity with different pore size distributions (PSDs). Then, we analyze the model sensitivity to the model parameters and compare the lognormal and fractal PSD models. Furthermore, the proposed model successfully predicts the experimental data of electrical conductivity for different samples from experiments that are part of this work and published data. The proposed model for characterizing electrical conductivity opens up new possibilities to describe the distribution and dynamics of liquid water with geoelectrical and electromagnetic techniques in frozen environments.

Automated summary

Determining and monitoring liquid water saturation and permeability in saturated frozen porous media are critical issues in cold regions. This study uses geophysical methods to non-invasively determine and monitor liquid water saturation and permeability in frozen porous media. The proposed model successfully predicts the electrical conductivity of frozen soils using different pore size distributions and provides new possibilities for describing the distribution and dynamics of liquid water in frozen environments using geoelectrical and electromagnetic techniques.