Abstract: Transient electromagnetic method (TEM) has become an important geophysical survey method as it is capable of detecting in large depth with accurate positioning unaffected by topographic fluctuations. The three-dimensional forward method of transient electromagnetic method mainly includes finite element method, finite difference method, and integral equation method. In the present paper, finite element method is applied to the 3D forward modelling of transient electromagnetic for various hidden dangers of embankments. Comparison between the 3D forward computation results and the inversion results of field measured data demonstrated that the transient electromagnetic method is sensitive to low resistivity zone, thus having good detection effect for low resistivity anomalous zone of different shapes. Therefore, it is feasible to adopt transient electromagnetic method for the rapid survey of embankment’s hidden dangers. The research results in this paper can be used for reference in applying geophysical prospecting technology to the detection of hidden dangers in embankments.

Key words: detecting hidden danger of embankment, transient electromagnetic method, finite element method, 3D forward modelling, low resistance zone