巷道掘进瞬变电磁超前探测干扰信号剔除

Elimination on Interference Signals of Transient Electromagnetic Advanced Detection in Mine Roadway Heading

瞬变电磁方法已广泛应用于井下巷道超前探水。受巷道测试条件限制,现场数据采集受到多种因素干扰,其质量严重下降,从而降低了测试结果的可靠性。为提高观测数据质量,通过对现场背景电磁噪声信号的采集分析,排除背景强电磁干扰;根据发射电流的关断特征,结合接收线圈的系统特性,采用理论计算方式,剔除一次场干扰;通过井下实体模型试验,构建锚杆金属干扰体的响应特征,并进行叠加校正,实现对金属干扰信号的剔除。同时,利用观测数据的中心差商代替求导,导入接收线圈特性方程,获取地质体真实响应数据。综合分析各干扰信号特点,设计了干扰信号剔除流程。现场应用结果表明:剔除干扰信号后的视电阻率成像结果与实际地质体的电性特征一致性好,对含水区的分辨能力得到增强;同时,提高了该方法的浅层勘探能力。

The transient electromagnetic method has been widely applied to the advanced water detection of the mine roadway in underground mine.Due to the limit of the test condition in the mine roadway and the site data collection affected by the interference of several factors,the quality of the method was seriously declined and thus the reliability of the test results was reduced.In order to improve the quality of the observed data,with the collection analysis on the electromagnetic noise signals of the mine site background,the background high electromagnetic interferences were eliminated.According to the turn-off features of the emission current and in combination with the system characteristics of the receiving coil,the theoretical calculation method was applied to eliminate the once site interference.With the physical model tested in the underground mine and the establishment on the response characteristics of the bolt metal interference mass,an overlay correction was conducted and the elimination of the metal interference signals was realized.Meanwhile the central difference quotient of the observed data was applied to replace the derivation and the characteristic equation of the receiving coil was introduced to obtain the real response data of the geological mass.Each interference signal features was comprehensively analyzed and the elimination process flow of the interference signals was designed.The site application results showed that after the elimination of the interference signals,the imaging results of the apparent resistivity had a good consistency to the electric features of the real geological mass and the resolution capacity of the water bearing zone was improved.Meanwhile,the shallow depth exploration capacity of the method was improved.