Research on localization technology for dam leakage channels based on coupled electric and magnetic fields

Based on the mechanism of current density formation under natural electric fields and artificial stable current sources, this study proposes a multi-physics coupling theory involving seepage fields, ion diffusion fields, and stable electric fields induced by leakage. Coupling equations and boundary conditions for electric and magnetic fields were formulated based on fundamental laws of Ohm’s law and Biot–Savart law. A finite element-infinite element numerical simulation method was used to achieve three-dimensional response characteristics of coupled electric and magnetic fields in embankment leakage scenarios by incorporating conversion relationships for the water content, resistivity, and ion concentration. Based on the distribution characteristics of coupled electric and magnetic fields, a detection technique for locating leakage channels in embankment dam was proposed. This technique enhances leakage channel signals by applying an artificial stable electric field on both upstream and downstream sides of the channel. Subsequently, precise localization of leakage risks is achieved by observing two components of the coupled electric field or three components of the magnetic field on the dam surface. This new method was applied to locate the leakage channel at a pond in Hangzhou. The detection results have been validated by the drilling results, which demonstrated that this technique offers higher precision and better detection performance compared to traditional high-density resistivity methods. This work validate the effectiveness of the coupled electric and magnetic field-based detection method and provide a novel solution for embankment leakage detection.