煤岩变形破裂微结构电磁性及低频电磁辐射机理

Coal rock is a kind of porous, heterogeneous and anisotropic solid medium. During the process of deformation and rupture, it can generate broadband electromagnetic radiation (EMR), which concentrates on low frequency. Presently, the mechanism of coal rock EMR remains unclear, leading to the lack of rigorous theoretical support for the application of this EMR technique. This project seeks to establish the direct relationship between the electromagnetic (EM) signal frequency and the rupture of coal rock, aiming to answer the basic scientific problems: why coal rock rupture causes EMR of low-frequency bands (VLF, LF, MF bands), and what kind of rupture can generate what frequency of EMR. Finally, the mechanism of EMR of low-frequency bands is tried best to be illustrated. This project will study the polarity characteristics and potential charge performance of typical coal rock microstructures, determining the microstructure basis of EMR from coal rock. The EM properties of coal rock microstructure under static and dynamic loading will also be investigated in depth. The macroscopic characteristics of typical coal rock deformation and fracture, the waveform and amplitude-frequency characteristics of EMR of low-frequency bands will be studied. Based on the former study, the mechanism of the generation, relative motion, disappearance of the electrical property and how to induce EMR during the process of coal rock rupture will be analyzed, so as to reveal the mechanism of EMR of low-frequency bands. The stress-rupture-EMR of low-frequency bands coupling model will be established on macroscale. According to the coupling model, the instability early warning methods for coal rock will be proposed, which will be verified through field tests. The research results will be of important theoretical and practical significance to further improve the EMR theory of coal rock, and enhance the accuracy and reliability of this technology in practical application.

煤岩是多孔隙、裂隙非均质固体介质，其变形破裂能产生以低频为主的宽频电磁辐射。目前，煤岩变形破裂电磁辐射机理尚不清晰，使该技术应用缺乏严谨的理论支撑。本项目力求建立电磁辐射频率与破裂的直接关系，回答煤岩破裂为什么产生低频（VLF、LF、MF频段）电磁辐射、什么样的破裂能产生什么频率的电磁辐射的基础科学问题，揭示煤岩变形破裂的低频电磁辐射机理。本项目将研究典型煤岩微结构的极性特征及潜在带电性，确定电磁辐射的微结构基础，并揭示微结构静态及动态加载下的电磁性；研究典型煤岩变形破裂宏观特征规律，揭示该过程低频电磁辐射的波形特征及幅频特性；研究煤岩变形破裂过程电性产生、相对运动、消失及其诱发电磁辐射的机制，揭示低频电磁辐射机理，并建立煤岩宏观加载破裂的应力-破裂-低频电磁辐射耦合模型；基于模型建立受载煤岩失稳预警方法，并进行现场验证。研究成果可进一步完善煤岩电磁辐射理论，提高技术应用的可靠性与准确率。

煤岩是多孔隙、裂隙非均质固体介质，其变形破裂能产生以低频为主的宽频电磁辐射。目前，煤岩变形破裂电磁辐射机理尚不清晰，使该技术应用缺乏严谨的理论支撑。本项目研究发现了煤岩变形破裂微结构电磁性，揭示了低频电磁辐射机理，并进行了验证与初步应用。主要成果如下：.①研究得出了典型煤岩电磁信号参数在静态时的存在状态，揭示了静态条件下典型煤岩微结构的电磁性，确定了煤岩破裂电磁辐射的微结构基础；②建立了煤岩微结构动态加载方法，研究了不同加载条件下煤岩微结构变化特征及电磁参数的响应规律，揭示了微结构静态及动态加载下的电磁性；③建立了煤岩加载低频电磁辐射响应实验系统，揭示了煤岩典型破裂事件诱发的低频电磁辐射的波形特征及幅频特性，得出了电磁辐射信号波形、频率、强度与上述破裂特征参数的相关关系，揭示了典型煤岩变形破裂过程低频电磁辐射精细化特征规律；④得出了煤岩破坏过程电性产生、相对运动、消失及其诱发电磁辐射的机制，揭示了低频电磁辐射机理，并建立了煤岩宏观加载破裂的应力-破裂-低频电磁辐射耦合模型；⑤从电磁辐射频域角度建立了煤岩稳定性评估及临界失稳判识方法，现场测试了工作面采掘扰动、老顶来压等已知震源诱发的低频电磁辐射信号特征，对上述理论进行了验证。依托本项目，出版英文专著1部，发表学术论文41篇，其中SCI论文25篇；主持制定行业标准2项，申请发明专利9项，登记软件著作权2项；获省部级科技进步一等奖1项，二等奖4项；培养博士生3名，硕士生6名；国际学术交流访学4人。.研究成果回答了煤岩破裂为什么产生低频段电磁辐射、什么样的破裂能产生什么频率的电磁辐射的基础科学问题，进一步完善了煤岩电磁辐射理论；同时将进一步促进电磁辐射技术在矿山地下工程领域的应用，提高动力灾害预警效率。