Assessing Electrode Configuration Performance in Imaging Deep Concrete Piles Using 2D Electrical Resistivity Surveys

For rapid site investigation and buried foundation imaging, the electrical resistivity method is widely applied. This study concentrates on imaging a concrete pile foundation of 0.5 m in width and 200 Ohm.m of resistivity buried in a host background of 100 Ohm.m. The most popular electrode configurations are applied using different electrode spacing (0.1, 0.25, 0.5, and 1 m). Multiple data sets are numerically generated using the finite difference method and then inverted using the robust inversion algorithm constructed in the computer software RES2DINV. The obtained 2D resistivity images reveal the ability of dipole-dipole and equatorial dipole-dipole configurations in detecting the pile; the Wenner configuration shows less ability, and the gradient, multiple gradient, and pole-pole configurations are the poorest. In addition, most of the trialed configurations have detected the top part of the pile rather than the bottom. It is recommended, therefore, to apply high-resolution surveys using the dipole-dipole, equatorial dipole-dipole and the Wenner electrode configurations.