Ohmic Conductivity of a Compacted Silty Clay

Abstract

In its natural state, loess can be considered as an unstable soil, which develops large deformations when moistened. In Argentina, loess is used in most Geotechnical constructions, including embankments and liners. The interest of this work to evaluate the potential application of electrical conductivity measurements for monitoring the effects introduced by remolding and compaction in the soil. Samples of loess were compacted at varied densities and mixed with electrolytes of different concentrations. Electrical conductivity was measured with a two electrode cell. The effects introduced on the measured conductivity by frequency, degree of saturation, soil density, temperature, and electrolyte type and concentration are addressed. Additionally, hydraulic permeability tests were performed on compacted specimens of loess and the relationship between electrical and hydraulic conductivity was determined. It is concluded here that the ohmic conductivity of compacted specimens depends mainly on the salt concentration in the pore fluid, and volumetric water content. The effect of compaction density was observed to be less significant. The whole behavior of electric conductivity of loess is well described by the Archie’s law.