瞬变电磁虚拟波场反演法在井下超前探测中的应用

Inversion method of transient electromagnetic virtual wave-field applied to advance detection in underground mine

为解决矿井瞬变电磁超前探测对异常体规模、位置解释精度低的问题,采用全波形反演法对波场反变换得到的虚拟波场数据进行速度分析,提出了瞬变电磁虚拟波场反演成像方法。针对掘进工作面前方的隐伏水害,分别采用三维数值模型、物理模拟和工程实例对方法进行了实用性和有效性验证。研究结果表明:该方法不仅对异常幅值大于30%的含水断层模型的两层电性界面反应明显,对异常幅值小于5%的充水巷道模型也具有相同精度的效果;此外,该方法可将矿井瞬变电磁超前探测的浅部盲区范围降至0,能准确定位低阻异常体实际位置。

In order to solve a low accuracy problems to explain the abnormal body size and location advance detected by the mine transient electromagnetic,a total waveform inversion method was applied to the velocity analysis on the data of the virtual wave-field obtained with the wave-field contra-variant and the inversion imaging method of the transient electromagnetic virtual wave-field was provided. According to the hidden water disaster in the front of the heading face,a 3D numerical model,physical simulation and engineering cases were applied to the practical and effective verification of the method. The study results showed that the method could not only well reflect the two layer electrical interfaces of the water bearing fault model with abnormal amplitude over 30% and could have same accurate effect of the water flooded roadway model with the abnormal amplitude less than 5%. In addition,the method could reduce the shallow depth blind area to 0 by the advance detection of the mine transient electromagnetic and could accurately position the actual location of the low resistance abnormal body.