The effects of water content and water resistivity on the dispersion of resistivity and dielectric constant in quartz sand in the frequency range 10^2 to 10^8 Hz

Abstract

Using modifications of previously developed methods, measurements were made of the resistivity and the dielectric constant of two similar quartz sands of different porosity over the frequency range 102-108 Hertz for various water contents and water resistivities. Dispersion is pronounced in all the resistivity data above 106 Hz. As water content decreases, resistivity dispersion becomes noticeable at lower frequencies. The resistivity data at all frequencies, however, fit an empirical prediction formula relating observed resistivity to water saturation and resistivity of the saturated sample. The data suggest that the dispersion of resistivity of some earth materials with frequency may be predicted on the basis of curve matching of the data obtained in this investigation with the resistivity of the material at a frequency of 100 Hz or lower. The dispersion of dielectric constant with frequency is pronounced at all frequencies, being more pronounced with increasing water content. The shape of the dispersion curve is dependent on the resistivity of the water in the sample.