堤防隐患瞬变电磁三维正演模拟及分析

Three-dimensional Forward Modeling and Analysis of Transient Electromagnetic for Detecting Embankment’s Hidden Danger

瞬变电磁法具有定位准确、探测深度大、不受地形起伏影响等优点,已经成为一种重要的地球物理勘测方式。为研究瞬变电磁法在堤防隐患探测中的应用,采用有限单元法对多种堤防隐患进行瞬变电磁三维正演模拟计算,通过对比三维正演计算结果和野外实测数据反演结果可以发现瞬变电磁法对低阻体敏感,对不同形态的低阻异常体探测效果均较好,因此采用瞬变电磁法进行堤防隐患快速普查的研究思路是可行的。研究成果可为物探技术在堤防隐患探测中的应用提供参考。

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.