浅层等值反磁通瞬变电磁在煤窑采空区中的应用

Application of Equal and Reverse Magnetic Flux Transient Electromagnetic Method for Shallow Subsurface Prospecting in the Coal Mine Goaf

铁路勘察设计中,查明煤窑采空区的分布对铁路设计以及后期运营具有重要意义。基于等值反磁通原理的瞬变电磁法是一种探测地下二次场的新方法。该方法通过将接收线圈至于反磁通平面,消除其暂态过程,接收纯净地下二次场。为此,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勘探中的应用,利用煤窑采空区与周围完整岩体的瞬变电磁法反演相对视电阻率的差异,在新建铁路渝昆线昭通车站的地球物理勘探中,准确探明采空区位置。通过与同测线地质资料对比,展示其良好的浅层勘探效果。

In railway survey and design,finding out the distribution of the coal mine goaf has important significance for the design and operation of railway.Based on the principle of equal and reverse magnetic flux,the transient electromagnetic method is a new tool for exploring the secondary electromagnetic field.According to the method,put receiving coils on the plane of reverse magnetic flux to eliminate the transient process of the coils.Then the pure electromagnetic field is obtained.The paper will study the transient electromagnetic method and its application to the railway engineering exploration.The difference of relative apparent resistivity is inverted using transient electromagnetic method of coal mine goaf and the surrounding intact rock mass and the location of the coal mine goaf is accurately ascertained in geophysical exploration in Zhaotong East Station of the new Chongging-Kunning railway line.Its better effect on the shallow exploration will be displayed by compared with the geologic data of same survey line.