ABSTRACT
The electrical resistivity technique is one as the most commonly used geophysical methods for subsurface exploration. This method not only possesses high potential to explore large area and deep depths economically but also ideally suits to interpreat variety of subsurface conditions with fair degree of accuracy. For proper interpreation of field electrical resisitivity sounding data for rock classification and characterisation it is imperative to understand influence of various factors on electrical resisivity of rocks. Towards this ends various researchers have reported the influence of various physical and environmental factors on electrical resistivity of rocks. Also reported are dependence/corelationships of geotechnical properties of rocks with electrical resisitivity. This paper presents the synthesis of typical available experimental data from reported works on electrical resisitivity of rocks. This is then critically examined and analysed to understand influence of various physical properties and environmental factors on electrical resistivity and to obtain strength-resistivity behaviour of rocks which inturn may help in rational interpreation of electrical resistivity sounding data for classification and characterisation of rocks. The porosity and moisture content are observed to be the most significant physical properties influencing rock resistivity. Confining pressure affects the electrical resistivity significantly. The electrical resistivity shows marked decrease with axial stress. Fair correlations exists between electrical resistivity and strength and elastic constants.
