Interpretation of Fines Content and Density Dependencies of Electrical Resistivity for Unsaturated Sandy Soils

Abstract

The degree of saturation, density, and fines content affect electrical resistivity of soil. While the dependence of electrical resistivity on the degree of saturation is well understood—since electricity primarily flows through pore water—the effects of fines content and density on resistivity, particularly under unsaturated conditions, are not yet fully clear. In this study, electrical resistivity was measured on soil specimens with varying degrees of saturation, density and fines content. The mechanisms by which electrical resistivity depends on density and fines content were interpreted by focusing on the microscopic morphology of pore water and the behavior of ions within the pore water. It was found that at lower degrees of saturation, the effect of density on electrical resistivity becomes greater, while the effect of fines content becomes smaller. Based on these findings, the potential for utilizing electrical resistivity in soil compaction management is discussed.