Frequency-Domain Analysis Of Electrical Dispersion Of Soils

A theoretical frequency-domain general solution for the electric dispersion of soils is presented here. The theory rigorously takes into account the effects of particle shape, frequency, soil mineralogy, pore fluid type, porosity, solid-fluid interaction, anisotropy, and direction of measurement. The electric dispersion of soils is affected by the preceding basic soil parameters and the ratio of effective permittivities (β_ε= ε₂/ε¹) and conductivities (β_σ = σ₂/σ₁) of the solid particles (subscript 2) and pore fluid (subscript 1). In general, the response can be categorized into three cases, β_σ < β_ε < 1, < β_ε < β_σ1, and β_ε < 1 < β_σ, each representing a distinct soil-fluid interaction phenomena. No dispersion is observed for β_σ = β_ε. Effects of factors such as particle shape, orientation, etc. on dispersion are different in each case. Good comparisons are observed between the theory and experimental data. Results indicate that frequency-domain interpretation of the dispersion data be used to predict soil microstructure, soil and pore fluid type and interaction, porosity, particle characteristics, anisotropy, and geoenvironmental conditions at a site. These parameters can then be related to engineering soil behavior parameters in a fundamental way.