Construction of structural reference model for ERT data inversion in heavy metal contaminated sites surveys

Electrical resistivity tomography (ERT) surveys can provide useful information on heavy metal contaminated sites assessment. Structural reference model is introduced as a constraint to guide ERT data inversion in ERT survey. In this paper, we propose a novel method, which integrate soil physical and chemical information into structural reference model construction for ERT data inversion to improve the accuracy of inversion results. The reference model consists of two parts: contaminated area and uncontaminated area. The scope of contaminated areas is recognised using soil physical and chemical properties and the apparent resistivity data extracted from the ERT profile at the borehole location, and then the resistivity distribution of reference model is set according to the average resistivity of soil samples. The accuracy of the proposed method is evaluated with two numerical experiments. The experiment results of synthetic models show that the structural reference model constructed by the proposed method is close to the synthetic model and effectively improves the inversion results.