导水断层给井下安全生产带来严重的灾害隐患,为了推进矿井瞬变电磁法的实用性,开展了导水断层瞬变电磁场响应特征研究。基于三维低阻薄板地电模型,采用理论分析、物理模拟相结合的方式,探讨了板状导体上感应涡旋电流与一次场的激发关系,研究了走向导水断层矿井瞬变电磁超前探测视电阻率响应特征。研究结果表明:①感应涡旋电流主要与板状体有效切割一次场磁力线多少有关,激励角30°~60°时,感应涡旋电流较强;②矿井瞬变电磁超前探测扇形视电阻率等值线图上,走向导水断层呈现左右对称分布2个低阻异常夹中间1个高阻异常的响应特征。研究结果应用于工程实践,取得了良好效果。
To promote the practicability of mine transient electromagnetic method, the paper studies the response characteristics of water-conductive strike fault in mine transient electromagnetic field. Based on the geo-electrical model of 3D conductive sheet, according to the theoretical analysis and the physical simulation, it is discussed how the eddy current in the sheet vary with the exciting position of the first field, and studies the apparent resistivity response of the water-conductive strike fault by the mine transient electromagnetic advance detection ( MTEAD ) . The results show: ① the induced eddy current is decided mainly by the number of the magnetic line, which is cut by the sheet, and it is stronger when the exciting angle is 30°~60°; ② on the apparent resistivity contour map of MTEAD, the response of the water-conductive strike fault is one middle high resistivity abnormal area with two low resistivity abnormal areas on the left and right sides symmetrically. The result was applied in engineering practice, and gained good effects.