矿用高分辨电法监测系统设计

Design of high-resolution electrical monitoring system for mining

电阻率法是煤矿水害潜在风险判别、监测和预警的重要手段,也是矿井地质信息透明化的重要数据来源。进行井下电法监测时,单一的单巷电剖面法或双巷电透视法对富水区定位精度不高。此外,由于大规模电气设备产生的电磁干扰越来越强,传统的电法监测设备难以取得有效数据。针对上述问题,设计了一种矿用高分辨电法监测系统,该系统可在采动过程中实时进行单巷电剖面法及双巷电透视法数据的自动采集,并利用2种观测数据进行约束反演成像,提升了低阻异常体的成像分辨率。设计了二级放大及工频滤波电路,在进行电剖面和电透视数据采集时配置不同的采样时序、采样频率及数字滤波器,以抑制大规模电气设备对电法响应信号的干扰。性能测试结果表明,矿用高分辨电法监测系统可在噪声环境下有效分辨1μV目标信号,在电透视模式和电剖面模式下,工频抑制比分别不低于35 dB和80 dB。水槽物理模拟试验结果表明,该系统可有效分辨在工作面倾向约为300 m时底板下60 m处大小约为10 m3的低阻异常体。测试和试验结果验证了该系统具有较强的工频干扰和随机干扰抑制能力,能够在煤矿有限的观测空间和强干扰条件下获得可靠有效的数据,提高了反演结果中异常体的成像分辨率。

The resistivity method is an important means for identifying,monitoring,and warning potential risks of coal mine water hazards,and also an important data source for transparency of mine geological information.When conducting underground electrical monitoring,the positioning precision of single roadway electrical profiling method or double roadway electrical perspective method for water rich areas is not high.In addition,due to the increasingly strong electromagnetic interference generated by large-scale electrical equipment,traditional electrical monitoring equipment is difficult to obtain effective data.In order to solve the above problems,a high-resolution electrical monitoring system for mining has been designed.The system can automatically collect data from single roadway electrical profile method and double roadway electrical perspective method in real-time during the mining process.The system uses two types of observation data for constrained inversion imaging,improving the imaging resolution of low resistance anomalous bodies.A two-stage amplification and power frequency filtering circuit is designed to configure different sampling timing,sampling frequency,and digital filters during the collection of electrical profile and perspective data.It will suppress the interference of large-scale electrical equipment on electrical response signals.The performance test results show that the high-resolution electrical monitoring system for mining can effectively distinguish 1μV target signal in noisy environments.The power frequency suppression ratio is not less than 35 dB and 80 dB in the electric perspective mode and electric profile mode,respectively.The results of the physical simulation test in the water tank indicate that the system can effectively distinguish low resistance anomalous bodies with a size of approximately 10 m^(2) at a depth of 60 meters below the floor when the working face is inclined towards about 300 meters.The test and experimental results have verified that the system has strong power frequency interference and random interference suppression capabilities.The system can obtain reliable and effective data under limited observation space and strong interference conditions in coal mines,improving the imaging resolution of abnormal bodies in inversion results.