Research on the detection of leakage points in vertical barrier walls using a combined method of ERT and tracer methods.

In order to improve the detection accuracy of vertical barrier leakage, three contamination leakage working conditions, including point leakage only, point and vertical leakage, and horizontal leakage, were simulated by small-scale soil tank tests. The dynamic evolution of soil resistivity over time was monitored by electrical resistivity tomography (ERT). The accuracy of the ERT detection results was validated through thermal tracer method, chloride tracer method, and soil true resistivity experiments. The results indicate that the resistivity profiles at different times can more accurately reflect information on the location of leakage points, the extent of contamination plumes, and the migration pathways of pollutants under different working conditions. The extent of anomalous areas in resistivity profiles is a crucial factor in representing the geometric shape of pollution leakage. However, the preferential seepage or lateral migration of contaminant in the soil significantly reduces the detection accuracy of ERT for identifying leakage points. The thermal tracer method and the chloride tracer method can produce better complementary interpretations of ERT monitoring results. The measurement points near the leakage point exhibit faster temperature response rates, which can serve as a characteristic for identifying the location of leakage points. Compared with the thermal tracer method, the chloride tracer method can monitor the migration of contaminants over a larger range. Therefore, the proposed combined diagnostic detection method in this paper presents a feasible solution with promising engineering applications in leakage detection for vertical barrier barriers.