Estimation of Permeability of Fine-Grained Soils from High-Frequency Electromagnetic Measurements

Abstract

The geometric properties of the pore space govern the electrical and hydraulic properties of soils. Recognizing this commonality, this paper proposes a new approach to determine permeability from high-frequency electromagnetic (HF–EM) measurements on geomaterials undergoing evaporative dewatering. Two materials have been used; (1) kaolin, a reference geomaterial; and (2) a dredged sediment sample from the Port of Brisbane (PoB) reclamation site (Queensland, Australia). Based on a dielectric mixture equation that integrates Archie's parameters, the evolution of formation factors as a functions of porosity have been derived. Several models that are available in the literature have been used to estimate proxies for geometric length scales for pore radii. With knowledge of the formation factors and proxies for pore radii as functions of porosity, permeabilities of the materials under saturated conditions have been estimated. The results have been compared with experimentally obtained permeabilities. Using the formation factors from HF–EM measurements and two of the proxies for pore radii (hydraulic and characteristic pore radii, as defined in this paper), a good degree of agreement with the experimental data has been obtained within a variation in one-order of magnitude for kaolin. For the PoB material, the use of hydraulic pore radius yielded the best estimation of permeability.