Numerical Simulation Research on Leakage Detection of Underground Diaphragm Wall Based on Cross-Well Electrical Method

In deep foundation pit engineering, leakage of underground diaphragm walls poses a serious threat to construction safety and the surrounding environment. This study employs finite element numerical simulation to investigate the detection of such leakage using the cross-well electrical method. The influence of acquisition device, electrode spacing, and well spacing on detection performance is systematically analyzed. Additionally, the accuracy of apparent resistivity imaging and leakage localization is assessed under various leakage conditions, including leakage point resistivity, leakage size, leakage depth, and the number of leakage points. The results demonstrate that the AM-BN dipole–dipole acquisition device offers superior localization accuracy and deeper penetration capability. Notably, reducing the electrode spacing below 2 m significantly enhances detection precision and effectively suppresses spurious anomaly interference. The cross-well electrical method exhibits robust performance in identifying a broad range of leakage scenarios. Moreover, a reliable localization approach by identifying the minimum value location of the apparent resistivity curve is proposed.