科研之友
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摘要
Electromagnetic radiation (EMR) anomalies preceding or accompanying coal and rock dynamic disasters have been reported for many years, but the mechanism that produces these anomalies is still unclear. To investigate the role that charge separation plays in these electromagnetic (EM) anomalies, uniaxial compression experiments on three different brittle materials: coal, marble, and polymethyl methacrylate were conducted. The results of the experiments indicate that EMRs are observed in piezoelectric and nonpiezoelectric materials but EM anomalies are only observed when abrupt stress drops occur. The EMR energy rate increases with the magnitude of the stress drop, and those two variables are related by a polynomial function. The charge separation responsible for the anomalies occurs on the newly generated cracks when chemical bonds are broken. A charge distribution model has been established for this phenomenon. Based on this model, the coupling relationship between EM energy densityw and charge density s has been determined by theoretical analysis. According to this analysis, w is proportional to sigma(2). In addition, the relationship between sigma and surface energy has been established, and it indicates that s increases with (1) the stress to which the surrounding material is subjected and (2) the length of newly generated cracks. Research findings reported should provide a more detailed understanding of the EM anomalies when coal and rock dynamic disasters occur and provide guidance for developing warning strategies for mine safety.
- 出版日期2018-12
- 单位中国矿业大学（北京）
