Electrical Resistivity of Jointed Rock and its Correlation to Elastic Wave Velocity
In order to interpret resistivity profiles derived from electrical and electromagnetic surveys, it is necessary to study the influence of joints on rock resistivity. In this paper, the resistivity of a rock mass is expressed by the resistivity model in which intact rock resistivity and fracture resistivity are regarded in parallel, and by introducing a coefficient α that varies with the state of fracture, we generalized this model for a rock mass that includes various fractures. To confirm this model experimentally, the results of calculation were compared with the experimental results. When α was 0.3, the calculation results agreed well with the experimental results. Lastly, as elastic wave velocity is useful for rock mass evaluation, we derived an equation that indicated the correlation of resistivity and elastic wave velocity for fractured specimens. We confirmed that this equation was applicable under confining pressure.