煤岩破坏电磁辐射定位技术方法

Electromagnetic radiation location technology for coal and rock failure

煤岩电磁辐射技术作为一种无损、实时、非接触、前兆性强的地球物理监测方法,在煤岩结构稳定性及应力状态评估、煤岩动力灾害监测预警中发挥了重要作用。然而,当前该技术主要通过电磁前兆信号时序变化预警煤岩动力灾害,不能实现对灾害孕灾区域的定位,无法指导防治措施精准实施,从而制约了该技术的发展应用。对此,围绕煤岩破坏电磁辐射定位技术方法开展了系统研究。基于磁性多层膜材料的隧道磁电阻效应,研发了新型电磁矢量传感器,传感器在三轴方向上具有显著的独立性,互不干扰,对夹角余弦的响应表现出高线性度,为煤岩破坏电磁辐射定位奠定了基础,揭示了煤岩破坏电磁辐射的矢量特性。三分量电磁信号在时域上同步到达,波形存在明显差异,频域上信号主频一致,幅频分布相似,可视为主破裂产生的电磁场在3个方向上的分量。基于煤岩破坏发生时电荷分离、运动的过程,建立了等效的电磁辐射场源模型和煤岩破坏电磁辐射定位方程,并进行了数值模拟和实验验证,定位效果理想。研究成果是煤岩电磁辐射监测技术领域的原始创新,初步将该技术从预测“危险是否会发生?”拓展到预测“危险将在何处发生?”。研究旨在推动煤矿动力灾害监测预警技术装备的升级与创新,为我国煤矿智能化发展提供支撑。

As a nondestructive, real-time, non-contact and predictive geophysical monitoring method, the electromagnetic radiation technology plays an important role in evaluating structural stability and stress state of coal and rock, as well as monitoring and early warning on coal and rock dynamic disasters. At present, the time series changes of electromagnetic precursor signals are mainly used for the early warning of coal-rock dynamic disasters. The electromagnetic radiation technology has not yet been able to achieve the location of the disaster area. Therefore, it is impossible to guide the precise implementation of prevention and control measures, which restricts the development and application of this technology. In this regard, a systematic study has been carried out on the electromagnetic radiation location technology and method for coal and rock failure. A new type of electromagnetic vector sensor is developed according to the roadway magnetoresistance effect of magnetic multilayer film materials, which lays the foundation for electromagnetic radiation location. The sensor has significant independence in the three-axis direction, and the response to the cosine of the included angle shows high linearity. The vector characteristics of electromagnetic radiation from coal rock failure are revealed. In the time domain, the three-component electromagnetic signals arrive synchronously, and there are obvious differences between the waveforms. In the frequency domain, the dominant frequencies of the signals are the same, and the amplitude-frequency distributions are similar. They can be regarded as the components of the electromagnetic field generated by the main fracture in three orthogonal directions. Based on the process of charge separation and movement when coal and rock failure occur, an equivalent electromagnetic field source model and location equation are established. Then numerical simulation and experimental verification are carried out, and the ideal electromagnetic location effect is obtained. The research is a unique innovation in coal and rock electromagnetic radiation monitoring technology. The technology will enable the development from initially predicting the possibility of a hazard to predicting the area where the hazard will occur. It will promote the upgrading and innovation of coal mine monitoring and early warning technology and equipment for coal mine dynamic disaster, and strongly support the development of intelligent coal mines in China.