Two Dimensional ERT Simulations to Check the Integrity of Geomembranes at the Base of Landfill Bodies

In this paper, we present the results of electrical resistivity tomography (ERT) modellings to study the capability of the method in distinguishing a damaged geomembrane from an intact one below landfills. Different 2D synthetic models were defined in Res2dmod and the geomembrane was placed at a depth of 20-25 m from the ground level. Different scenarios were modelled moving from simple homogeneous landfill body to more realistic landfill above the insulating geomembrane. For each model, simulations were performed both for an intact geomembrane and for a damaged one. For the latter case, an area below the landfill polluted by the leachate was also modelled. Apparent resistivity pseudosections were calculated for the most common electrical arrays and then inverted with Res2dinv software. In this work, we present the results for the dipole-dipole array. The results showed distinguishable contrasts in resistivity values below the landfill between the intact and damaged situations provided that the survey spread is long enough to observe the resistivity values at depths quite larger than the geomembrane depth, especially when a conductive leachate layer is present just above the geomembrane.