On the geoelectrical characterization of an old landfill cover

Abstract : Two geoelectrical methods were used to characterize the state of an old French landfill cover. The objectives were to locate different materials used for the covering such as clay material or geomembrane and to identify heterogeneities that could be linked to possible defects in the cover due to fractures or cracks. These damages can induce preferential water pathways and unusual increase of leachate within the waste mass. The geoelectrical methods used were the electrical resistivity cartography with an Automatic Resistivity Profiling (ARP©) and the Self Potential method (SP). Results have put in evidence three distinct zones with different geoelectrical signatures that are correlated with three different phases of landfill covering. ARP also seems to have detected the presence of geomembrane installed all around the old landfill to improve its stability and geodrains over two closed alveoli. Local differences in apparent resistivity and self-potential signals have also been identified and could result in default in the clay cover due to thickness variations but also in different lithology, compaction and water content.