Fundamental Study on Resistivity of Soils

摘要

The resistivity of soils depends on grains size,porosity, water saturation, pore fluid resistivity, clay contents,temperature and so on. It is very important to understand therelationship between resistivity and such physical properties ofsoils, in order to interpret and evaluate ground conditions by usingresistivity data obtained for electrical prospectings.In this paper, to study the relationship between resistivity andphysical properties of soils, the resistivity of glass beads andcompacted soil samples both in saturated and unsaturatedconditions is measured. As the results, the resistivity of saturatedsoils depends mainly on porosity and clay contents, while that ofunsaturated soils is sensitive to compaction conditions, anddecreases with increasing water content until the optimum watercontent, that is the maximum dry density. But, the relationshipbetween resistivity and water saturation for soils is unique, beingindependent of compaction energy. Also, the resistivity ratiodecreases with increasing water saturation, followed by nosignificant change of resistivity ratio over 80 percent of watersaturation (the optimum water content).