矿井瞬变电磁金属干扰响应特征与校正方法

Response characteristics of metallic facilities and correction method on mine transient electromagnetic surveying

为了消除巷道内金属干扰对矿井瞬变电磁探测的影响,以常见的铁轨干扰源为例,采用井下实验方法系统分析了铁轨影响下不同距离、不同方向和不同探测模式等情况的瞬变电磁响应特征和影响规律,发现铁轨的存在导致感应电动势幅值增大,且不同情况的探测响应差异较大。通过计算有无干扰的归一化感应电动势比值得到各时间窗的校正系数,在其基础上提出拟合函数校正法,并将其应用到某煤矿工作面顶板探测中。实际应用结果表明:基于拟合函数的校正方法能够较好的剔除干扰异常,准确反映煤层顶板含水异常区的范围和赋水程度,明显提高金属干扰下矿井瞬变电磁探测含水异常区的准确性。

In order to eliminate the effect of metal facilities in the roadway on mine transient electromagnetic surveying,take trail interference sources for example,the transient electromagnetic response characteristics were analyzed by method of field experiment, with different distance, direction and modes between the wire-frame and tracks. It showed that the induction electromotive force amplitude increased under the influence of the tracks, and there was great difference of the response characteristics obtained in different condition. By calculating the induction electromotive force ratio of different time windows in interference and non-interference environment, the correction method of fitting function was proposed, and was used to correct the disturbed data of practical engineering. The results show that the fitting function correcting method can remove the abnormal interference in disturbed data, and better reflect the feature of abnormalities in coal seam roof, improving the detection accuracy of water anomaly by method of mine transient electromagnetic survey.