拟三维超浅层瞬变电磁在岩溶塌陷地区中的应用

The Application of Transient Electromagnetic Method for Pseudo-three-dimensional Ultra-shallow Subsurface Prospecting to Karst Collapse Areas

浅层勘探一直是电磁法领域的难点之一。基于等值反磁通原理的瞬变电磁法通过将接收线圈置于反磁通平面,消除其暂态过程,接收纯净地下二次场,实现浅层勘探。从等值反磁通瞬变电磁法原理出发,立足于在实际铁路工程岩溶塌陷地区中的应用,通过拟三维数据重建瞬变电磁反演资料,直观准确地展示塌陷腔体立体结构特征,成功实现中国西南岩溶地区拟三维超浅层瞬变电磁勘探。

Shallow exploration has always been one of the difficulties in the field of electromagnetic law.The transient electromagnetic method,based on the principle of equal and reverse magnetic flux,putting receiving coils on the plane of reverse magnetic flux eliminates the transient process of the coils.Then the pure electromagnetic field is obtained,and the shallow subsurface is prospected.The paper will study the transient electromagnetic method and its application to the railway engineering exploration of karst collapse areas;and will display the three-dimensional(3D)structure of karst collapse by reconstructing transient electromagnetic inversion with the help of pseudo-3D data,which marks the first success in applying transient electromagnetic method for pseudo-3D ultra-shallow subsurface prospecting to karst collapse areas in southwest China.