矿井瞬变电磁井下大型铁器干扰响应特征

Transient Electromagnetic Response Characteristics of Large Iron Interference in Mine

为从源头上提高巷道存在综掘机等大型铁器干扰条件下的矿井瞬变电磁法数据采集质量,采用三维有限元数值模拟、现场探测试验等手段,研究总结了大型铁器不同干扰程度下的瞬变电磁二次场响应特征和时空变化规律,得出了相应干扰规避措施。研究结果表明:对于综掘机等井下大型铁器,其近距离强干扰条件下的地层空间体感应电磁场会产生空间形态及时间分布的非均匀变化;大型铁器干扰响应对距离条件敏感,在现场有限后撤范围内,当距探测迎头4 m以外时,此类干扰影响可显著减弱,利于提高实际探测效果。

To improve the data acquisition quality from the source under circumstance of interferences by using mine transient electromagnetic method, we adopted 3 D finite element numerical simulation and field tests to analyze the responsing characteristics and variation laws of the induced electromagnetic field under different levels of interference from large iron, summarized the measure to weaken corresponding interference. The study results showed that： under condition of close range and strong interference of large iron like roadheader, the induced electromagnetic field of strata would produce non-uniform changes in spatial form and time distribution; the interference responses were sensitive to distance condition, the detecting effect would improve when the distance between the large iron and the detecting coil is beyond 4 m.