The phenomenon of electromagnetic radiation (EMR) generated by rock fracture is relatively common. Due to different properties of rock, the variation laws and distribution characteristics of signals in time and frequency domain are significantly different. In this paper, the uniaxial compression experiments of four different kinds of rocks were carried out under the same loading conditions. EMR response characteristics during loading were studied, and the relationship between EMR signal statistics and mechanical parameters or quartz contents of rocks were analyzed. However, quartz content is not a decisive factor since quartz-free rock can also produce significant EMR signals when it fractures. Quartz content does not stimulate the activity and intensity of EMR signals generated by rock fracture. For the same kind of rock, specimen with larger elastic modulus tend to exhibit higher EMR signal intensity. Activity of EMR signals is not strictly proportional to the compressive strength of rocks but affected by complex stress-induced crack events during the loading process. With the continuous evolution of cracks, the dominant frequency of EMR signal shifts from a higher band to a lower frequency. As the quartz content decreases, the dominant frequency of EMR signal appears in a higher frequency band.

中文翻译：

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岩石性质对单轴压缩过程中岩石破裂电磁辐射特性的影响

岩石破裂产生的电磁辐射（EMR）现象比较普遍。由于岩石的性质不同，信号在时域和频域的变化规律和分布特征也有显着差异。本文在相同加载条件下对四种不同类型的岩石进行了单轴压缩试验。研究了加载过程中的EMR响应特性，分析了EMR信号统计与岩石力学参数或石英含量之间的关系。然而，石英含量不是决定性因素，因为不含石英的岩石在破裂时也会产生显着的 EMR 信号。石英含量不会刺激岩石破裂产生的 EMR 信号的活性和强度。对于同一种岩石，具有较大弹性模量的试样往往表现出较高的 EMR 信号强度。EMR 信号的活动与岩石的抗压强度不严格成正比，而是受加载过程中复杂的应力引起的裂纹事件的影响。随着裂缝的不断演化，EMR信号的主频从较高频段向较低频段转移。随着石英含量的减少，EMR 信号的主频出现在更高的频段。