Determination of selected geotechnical properties of soil using electrical conductivity testing

The use of electrical conductivity measurements, at relatively low frequencies, has been shown to be an effective tool for characterizing soils for hydrogeological studies. Many of the properties that affect the hydraulic and mechanical behavior of a soil also affect the electrical response. Thus, there is a likelihood that electrical measurements of soils will provide useful information for predicting geotechnical parameters. This paper presents the results of efforts to develop an electrical conductivity testing system that can be used specifically to evaluate geotechnical properties of soils. The testing system consisted of a robust data acquisition and control system that allowed for autonomous testing of various sand-clay mixtures and a testing apparatus that was rugged enough to allow soil samples to be compacted directly into the cell. The testing apparatus utilized a multi-electrode configuration which facilitated the investigation of anisotropic electrical measurements of the compacted soil samples. The data obtained during the evaluation phase of this research showed that low-frequency electrical conductivity measurements are viable for evaluating and predicting geotechnical properties of soils such as void ratio and volumetric water content, and the use of the multi-electrode configuration is very promising for evaluating anisotropy in soils.