Electrical Dispersion in Relation to Soil Structure

The dielectric constant and conductivity of saturated clays vary with the frequency of alternating current in the range of 10⁶ to 10⁸ Hz. These variations can be used to reflect the influences of changes in fabric and structure-determining factors in clays, since conductivity and dielectric dispersion in the radio frequency range are influenced in a numerically significant and predictable manner by clay type and amount, water content, particle orientation, particle contact, and the nature of the heterogeneity and type and amount of electrolyte. A new compositional property, defined herein as the dielectric constant of the wet particles or aggregate, is shown to depend on the amount and type of clay, water content and to reflect the water-adsorbing capacity and fabric of a clay. Numerical values describing the compositional and geometrical properties of clay-water-electrolyte systems are obtained by representing the system by a simplified three-element electrical network.