岩土力学 ›› 2019, Vol. 40 ›› Issue (2): 481-488.doi: 10.16285/j.rsm.2017.1646

• 基础理论与实验研究 • 上一篇    下一篇

煤体静载破坏中低频磁场变化特征及产生机制研究

李成武,付 帅,解北京,李光耀,宛天宇   

  1. 中国矿业大学(北京) 资源与安全工程学院,北京 10008
  • 收稿日期:2017-11-02 出版日期:2019-02-11 发布日期:2019-02-13
  • 通讯作者: 付帅,男,1988年生,博士研究生,主要从事矿井动力灾害监测预警技术方面的研究。E-mail: dallasfushuai@163.com E-mail: lcw@cumtb.edu.cn
  • 作者简介:李成武,男,1969年生,博士,研究员,从事煤岩动力灾害预防与控制方面的教学与研究工作。
  • 基金资助:
    国家自然科学基金(No. 51274206);国家青年科学基金(No. 51404277)。

Characteristics and generation mechanism of low-frequency magnetic field generated during the damage of coal under static load

LI Cheng-wu, FU Shuai, XIE Bei-jing, LI Guang-yao, WAN Tian-yu   

  1. College of Resource and Safety Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
  • Received:2017-11-02 Online:2019-02-11 Published:2019-02-13
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (51274206) and the National Science Foundation for Young Scientists of China (51404277).

摘要: 为了研究煤体静载破坏中低频磁场变化特征及其产生机制,进一步完善煤矿动力灾害监测预警技术,通过室内试验、现场试验研究了煤体静载破坏中低频磁场时、频谱特征,并结合微震信号提出了低频磁信号的产生机制。结果表明:煤体静载破坏中所产生低频磁场信号强度为19~156 nT,信号最大幅值、能量与试样强度、加载速度均呈正相关关系。垂直于裂纹扩展面磁场最强,平行于裂纹扩展面磁场最弱。并结果微震信号提出了低频磁场产生机制。低频磁场与微震信号具有时、频域同步性,带电裂纹面随微震信号同频振荡为低频磁场产生机制。现场放炮破煤低频磁信号由簇状脉冲信号及小幅震荡信号组成,其中簇状脉冲成分产生于炮后振动波带动带电壁面的同频振动,而小幅震荡成分是巷帮煤壁趋向新应力平衡状态时发生的横向拉伸破坏及带电煤碎屑运移、摩擦及转动的结果。

关键词: 静载破坏, 低频磁场, 微震信号, 时频谱特征, 产生机制

Abstract: The aim of this paper is to study the characteristics and generation mechanism of the low-frequency magnetic field generated during the damage of coal under static load, and to complete the monitoring and warning technology of dynamic disasters in coal mine. Laboratory and field experiments were conducted to analyse the characteristics in time and frequency domain of low-frequency magnetic signal. Laboratory experiment results show that the strength of the generated magnetic field is in the range of 19-156 nT. Both the maximum amplitude and magnetic field energy have a positive correlation with the intensity of coal and loading speed. It also shows that the magnetic field perpendicular to crack surface is the strongest, while the magnetic field parallel to the crack surface is the weakest. Then, by combining with the micro-seismic signal, generation mechanism of the low-frequency magnetic field was proposed. Results reflect that the magnetic signal and micro-seismic signal are synchronous in the time and frequency domain, and oscillation of crack surface with charge leads to low-frequency magnetic field. Field test results indicate that the magnetic signal includes the cluster pulse signal and small amplitude oscillation signal. The cluster pulse signal is caused by the crack surface vibration generated from blasting. The small amplitude oscillation signal is the result of lateral tensile failure generated during the formation process of the new stress equilibrium in coal wall, and migration, friction and rotation of coal particles with charge.

Key words: damage by static load, low-frequency magnetic field, micro-seismic signal, characteristics in time and frequency domain, generation mechanism

中图分类号: 

  • TD 324
[1] 艾迪昊, 李成武, 赵越超, 李光耀, . 煤体静载破坏微震、电磁辐射及裂纹扩展特征研究[J]. 岩土力学, 2020, 41(6): 2043-2051.
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