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力受激电压变化影响的实验研究


由于岩石在负载下会产生电压，因此研究其电压特性对于防治矿井动力灾害和相应的次生灾害至关重要。本研究构建了单轴压缩下岩石材料的压力模拟电压 （PSV） 测试系统，以探究岩石 PSV 变化规律。同时，采用核磁共振测试系统研究了孔隙结构变化对 PSV 变化的影响机制。获得了以下有益的结果。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，这种现象仅在高负载速率下出现。不同类型岩石的 T2 光谱差异很大。花岗岩在载荷下破裂后，一些初级微孔转化为中孔和大孔，同时产生大量新的微孔。这些微孔隙激活了更多的岩石缺陷（位错和晶界），导致更高的平均 PSV 和峰值 PSV。大理石断裂后，许多原生微孔转变为中孔和大孔，新微孔的比例下降。因此，它的发电能力减弱。相比之下，砂岩含有更高比例的微孔隙。断裂后，尽管一些微孔转化为中孔和大孔，但会再次产生大量的微孔，从而产生相对较高的电压。总之，整体孔隙度的变化不能代表岩石的发电能力，结合裂缝的变化对其产生深远影响。 岩石发电能力的关键在于微裂纹的增加和连接。