等值反磁通瞬变电磁法在浅部采空区探测中的应用

The Application of Opposing Coils Transient Electromagnetic Method to Detect Shallow Goaf

地下采空区一直是地质勘察的重点与难点,它严重影响铁路工程的安全。中卫至兰州铁路客运专线经过一采砂砾场地形成的采空区(掏砂洞),这对该段铁路设计造成了很大影响。以该浅部采空区为例,针对地表有冻土层造成的接地电阻过高问题,采用等值反磁通瞬变电磁法进行探测,结合地质资料,圈出了采空区的分布位置、大小及形态。随后通过钻探验证了探测结果的可靠性,表明使用等值反磁通瞬变电磁法探测浅层采空区是可行且高效的。

Underground goaf is the key and difficult point in geological survey all the time, which affects the safety of railway engineering.This paper introduces a case of shallow goaf detection,Zhongwei-Lanzhou passenger dedicated line passes through a goaf formed by sand and gravel mining(sand mining hole),which has a great impact on the railway design of this section.Opposing coils transient electromagnetic method has been adopted to detect the high ground resistance caused by permafrost on the surface.Combined with geological data, the distribution, size and shape of goaf are circled. These results are proved to be reliable by geological drilling. Therefore, it is feasible and efficient to use opposing coils transient electromagnetic method to detect shallow goaf.