Abstract: Ensuring engineering safety is of utmost importance during the construction and maintenance of dams. Regular leakage inspections play a critical role in preventing potential engineering disasters. To precisely locate dam body leaks, we propose a transient electromagnetic detection method utilizing electrode excitation. The electrodes generate transient electromagnetic fields in the conducting medium at the moment of power supply, while the resulting response signal carries conductivity information of the medium. Leakage within the dam body induces changes in medium conductivity, consequently impacting the transient electromagnetic response. Notably, in high-resistance media like aquifers, the response signal propagates faster and exhibits larger signal values, which is conducive to improving the accuracy of identifying leakage point. Employing the electrode system, we implemented three detection schemes to measure leaks in the Guxian dam. By performing corridor-based transmission and underwater-based reception, as well as underwater transmission with reception at corridor steps, we identified the leakage position from both horizontal and vertical perspectives. Analysis of the measured data confirmed leakage at the transverse joints between the 2^# and 3^# sections, aligning with the actual situation.

Key words: leakage detection, transient electromagnetic method, electrode detection, dam, direct current method