A new logarithmic dielectric constant model of soils

Abstract

A series of experimental tests were conducted to analyze the change of dielectric constant with varied particle composition and moisture content, and the experimental data were compared with several commonly used dielectric constant models. Results show that both the empirical models and the volumetric mixing models are more applicable to sandy soils and will overestimate the dielectric constant of cohesive soils due to the neglect of the effect of bound water. Actually there are a large number of strong and weak bound water in cohesive soils and the dielectric constant of bound water is much smaller than that of free water. To describe the effect of mesoscopic particle composition and bound water, a new logarithmic dielectric constant model is put forward. The application of this model is verified by others' experimental data and the calculation of dielectric constant of cohesive soils can be more accurate with this model. The moisture condition of soils can be judged roughly according to the ratio of the increment of dielectric constant and volumetric water content.