Performance of Various Electrical Resistivity Configurations for Detecting Buried Tunnels Using 2D Electrical Resistivity Tomography Modelling

Abstract

This work aims to evaluate performance of 2D electrical resistivity modelling technique for detecting buried tunnels using various electrode configurations. A synthetic resistivity model was designed to explore the capability of Wenner, Wenner- Schlumberger, Dipole-Dipole, Pole-Dipole and Pole-Pole electrode configurations for detecting buried tunnels at different noise levels. 2D forward modelling (RES2DMOD) and 2D inversion (RES2DINV) software were implemented using blocky L1 norm optimization method. The results showed that the modelled tunnel can clearly be detected at 0% noise level due to the high resistivity contrast between the synthetic tunnel and the surrounding host materials. At 0-30% noise levels, the results indicated that dipole-dipole and Wenner- Schlumberger in the second order perform better than other configurations. This can be attributed to the characteristics features and sensitivity of these configurations for resolving the subsurface resistivity changes. It is suggested that these configurations are more suitable for detecting the buried structures. The results also showed that the inversion artifacts caused by high noise levels may smear the resistivity signature of the burred targets for particular configurations. Thus, obtaining high quality data ensures reliable resistivity interpretations. The study demonstrated the usefulness of the 2D numerical modelling for planning of electrical resistivity surveys.