Since rocks will generate voltage under load, studying their voltage characteristics is of prime importance for the prevention and control of mine dynamic disasters and the corresponding secondary disasters. In this study, a pressure stimulated voltage (PSV) test system for rock materials under uniaxial compression was constructed to explore the law of PSV variations of rocks. Meanwhile, a nuclear magnetic resonance test system was employed for investigating the influence mechanism of pore structure changes on PSV variations. The following beneficial results were obtained. A “double-peak” phenomenon is observed on the PSV curves of granite and sandstone, whereas, for marble, the phenomenon only appears under high loading rates. The T2 spectra of different types of rock differ greatly. After granite fractures under load, some primary micro-pores are converted into meso-pores and macro-pores, accompanied by the generation of substantial new micro-pores. These micro-pores activate more rock defects (dislocation and grain boundary), resulting in a higher average PSV and peak PSV. After marble fractures, numerous primary micro-pores are transformed into meso-pores and macro-pores, and the proportion of new micro-pores falls. Consequently, its electricity generation capacity weakens. In contrast, sandstone contains a higher proportion of micro-pores. After it fractures, despite the conversion of some micro-pores into meso-pores and macro-pores, abundant micro-pores are generated again, bringing about a relatively high voltage. In short, the changes in overall porosity cannot represent the electricity generation capacity of rock, and the changes in bound cracks exert a profoundly influence on it. The key to the electricity generation capacity of rock lies in the increase and connection of micro-cracks.

中文翻译：

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基于核磁共振的岩石孔隙结构对压激电压变化影响的实验研究


由于岩石在负载作用下会产生电压，研究其电压特性对于矿山动力灾害及相应次生灾害的防治具有重要意义。本研究构建了岩石材料单轴压缩压力刺激电压（PSV）测试系统，探索岩石PSV变化规律。同时，采用核磁共振测试系统研究孔隙结构变化对PSV变化的影响机制。获得了以下有益结果。在花岗岩和砂岩的 PSV 曲线上观察到“双峰”现象，而对于大理石，这种现象仅在高加载率下出现。不同类型岩石的T2谱差异很大。花岗岩在荷载作用下破裂后，部分原生微孔转变为中孔和大孔，并伴随大量新微孔的生成。这些微孔激活更多的岩石缺陷（位错和晶界），从而产生更高的平均 PSV 和峰值 PSV。大理岩断裂后，大量原生微孔转变为中孔和大孔，新生微孔比例下降。因此，其发电能力减弱。相比之下，砂岩含有较高比例的微孔。其破裂后，尽管部分微孔转变为中孔和大孔，但又再次产生丰富的微孔，带来较高的电压。总之，整体孔隙度的变化并不能代表岩石的发电能力，束缚裂隙的变化对其影响深远。 岩石发电能力的关键在于微裂纹的增加和连通。