How should an electrical resistivity tomography laboratory test cell be designed? Numerical investigation of error on electrical resistivity measurement

•Guidelines to design laboratory ERT measurements.•Numerical approch based on full 3D complete electrode modelling evaluation of ERT errors.•Evaluation of laboratory errors related to the positioning of electrodes and the geometry of cells.•For laboratory applications, we demonstrate that the impact of electrode diameter is negligible.

Among geophysical methods, the electrical resistivity tomography (ERT) method is one of the most commonly used for the study of hydrodynamical processes. The geophysical literature relates several laboratory-scale applications of this method. Unlike the measurements taken at the field scale, few authors have taken an interest in errors associated with apparent electrical resistivity, especially in the case of ERT data acquired in the laboratory. The objective of this paper is to show that laboratory errors related to the positioning of electrodes and the geometry of cells are significant on apparent resistivity measurements. The embedment and the position of the electrode were evaluated to quantify their impact on electrical resistivity measurement. To assess these impacts, the authors propose a 3D numerical modelling investigation based on the complete design of a laboratory test cell.