Application of electrical resistivity for the control of water content and density in loess

Abstract

Argentinean loess is a typical collapsible soil which strength and stiffness are mainly governed by water content and unit weight. Electrical resistivity of soils depends fundamentally from water content, porosity, and salt concentration in the pore fluid. The interest of this work is to discuss the applicability of electrical resistivity survey to predict variations in density and water content in loess. Samples of loess were prepared in laboratory at varied densities and water contents. The results show that loess resistivity depends mainly on water content and that soil density has little influence. Mapping water content distribution by means of resistivity measurements is possible if salt concentration in pore fluid is known in advance and assumed uniformly distributed in the whole soil mass. A real scale work is described here for which resistivity mapping was used successfully to evaluate distribution of water content in loess formation.