Compaction Control of Clayey Soils Using Electrical Resistivity Charts

Abstract

Traditionally, electrical resistivity tests are being used for geophysical characterization but the electrical properties of soils can also be explored for compaction control of geotechnical works. Theoretical relations for estimating the electrical resistivity can be derived based on the degree of saturation and can be plotted in a chart relating water content with dry volumetric weight. The curves for specific values of electrical resistivity considering different degrees of saturation and porosities define an electrical resistivity chart, which can be used for compaction control of clayey soils. However the contribution of the water adsorbed in the electrically charged clay minerals surfaces must be considered, as they increase electrical conductivity. This paper presents the results of an experimental study in which the electrical resistivity was measured in different specimens of white kaolin compacted with different voids ratio and molding water contents. Discussion is made over the influence on electrical resistivity of the structure induced by the compaction process. Experimental data allowed defining the resistivity chart for this clay, which differs from the theoretical chart defined based only in the degree of saturation. Considerations are done about how this information can be used in compaction control considering the definition of resistivity charts and different clayey soils.