Electrical resistivity-based rock mass classification for tunnelling

Abstract

Geophysical prospecting using electrical resistivity is one of the principal methods for subsurface exploration. However, the majority of such application methods are restricted to coarse descriptions of underground conditions. The Q-system is commonly used as a representative rock mass classification system in modern rock engineering because it properly captures the important characteristics of a rock mass. In this paper, electrical resistivity is related to the Q-system through theoretical analyses. The analyses are based on Coulombs law and Gauss law considering electrical characteristics of constituent parameters for rock mass classification such as joint thickness, joint condition, joint spacing, intact rock strength, and RQD. Analytical results are compared with experimental results. The comparison shows that the analytical results agree with the experimental results, and there is a strong correlation between electrical resistivity and rock mass classification.