王兰炜,张宇,张兴国,胡哲. 2023. 地电阻率观测中地铁杂散电流特征. 地震学报,45(2):285−301. doi: 10.11939/jass.20210197
引用本文: 王兰炜,张宇,张兴国,胡哲. 2023. 地电阻率观测中地铁杂散电流特征. 地震学报,45(2):285−301. doi: 10.11939/jass.20210197
Wang L W,Zhang Y,Zhang X G,Hu Z. 2023. Characteristics of subway stray current in geoelectrical resistivity observation. Acta Seismologica Sinica45(2):285−301. doi: 10.11939/jass.20210197
Citation: Wang L W,Zhang Y,Zhang X G,Hu Z. 2023. Characteristics of subway stray current in geoelectrical resistivity observation. Acta Seismologica Sinica45(2):285−301. doi: 10.11939/jass.20210197

地电阻率观测中地铁杂散电流特征

Characteristics of subway stray current in geoelectrical resistivity observation

  • 摘要: 在对地铁杂散电流产生机理的讨论的基础上,定量计算了地铁运行时杂散电流在地电阻率观测中所呈现的影响幅度,结果表明地铁杂散电流传播范围可以达到几十甚至上百千米。通过对城市周边的北京通州、天津青光、宝坻、塘沽、江苏江宁和辽宁新城子等六个地电阻率观测台站观测到的该类信号的研究,分析了其幅值、主要频率范围以及空间分布特征,结果表明该类信号的幅值从几mV至几十mV不等,与源距关系密切,周期主要集中在50—200 s范围内,在分析地震异常前兆信号时该类信号可使信噪比降低10—30 dB左右,其相对方差最大超出标准20倍左右。根据地铁运行时杂散电流传播的特征,本文提出了几种压制该类信号的措施,为识别地震前地电阻率异常信息及排除噪声提供依据。

     

    Abstract: The geoelectrical resistivity observation is one of the most important methods in the study of earthquake precursor, and the characteristics of the stray current during subway operation in the geoelectrical resistivity observation are useful for analyzing the geoelectric observation data and the anomaly variation before earthquakes. Based on the study on the generation mechanism, the quantitatively results of the influence of stray current on geoelectrical resistivity observation were given in this paper. The result shows that the effect distance can reach dozens or even a hundred kilometers. Through monitoring the stray current in some geoelectrical resistivity observation stations around cities, such as Tongzhou station in Beijing, Qingguang, Baodi and Tanggu stations in Tianjin, Jiangning station in Jiangsu and Xinchengzi station in Liaoning, the amplitude and frequency range of the stray current signal as well as its spatial distribution characteristics were analyzed. It shows that the amplitude of the signal ranges from several to tens millivolt, and the period range is mainly from 50 s to 200 s. Due to the influence of stray current, the signal-to-noise ratio is decreased by 10 to 30 dB, and the accuracy of the observation data is more than 20 times worse than the specified requirement. According to the characteristics of the stray current propagation, several methods which can be used to suppress the signal were proposed in this paper, and it will provide a foundation for the identification of anomaly information from the observation data and anti-interference technology study.

     

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