Generalized Archie's Law for Estimation of Soil Electrical Conductivity

Abstract Archie's law, which is an empirical relationship between the electrical conductivity of rocks and their porosity, has been used widely for saturated rocks, while Archie's second law has been developed for unsaturated rocks. Both of these laws assume that the rock matrix is non-conducting and the conduction takes place through the pore-solution only. However, not many efforts have been made by the researchers to check suitability and applicability of Archie's law to the saturated or unsaturated states of the soils. Hence, a generalized Archie's law for soils, by incorporating their physical properties, volumetric moisture content, and bulk and pore-solution conductivities, was attempted in this study utilizing the data available in the literature. Further, to demonstrate the validity of this law, four soils with entirely different properties were used. These soils were characterized by conducting conventional laboratory tests, and their bulk and pore-solution conductivities were determined with the help of an impedance analyzer and a pressure membrane extractor.