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通过对干燥和饱水花岗岩进行单轴加载声发射实验和扫描电镜实验,研究饱水对花岗岩破坏前声发射平静期的影响。结果表明:干燥和饱水花岗岩破裂前声发射事件率均出现平静期,干燥花岗岩在峰值载荷的54.89%时进入声发射平静期,饱水花岗岩约为峰值载荷的89.87%;干燥花岗岩平静期内AE事件率小且恒定,AE能率较高,饱水后平静期内AE事件率增大,AE能率减小;干燥花岗岩平静期内声发射波形信号的熵值为1.5~2.5,饱水花岗岩为0.5~1.5;饱水改变了花岗岩的微观破裂模式,这为水是如何影响岩石的声发射特征提供了理论依据。实验结果丰富了对岩石声发射平静期的认识,这对岩石破裂声发射监测中前兆现象的识别具有重要意义。
Through the uniaxial loading acoustic emission experiment and scanning electron microscopy experiment on dry and saturated granite, the effect of saturated water on the acoustic emission calm period before granite failure was studied. The results show that the acoustic emission events of both dry and saturated granite appear to be quiet before the rupture. The dry granite enters the acoustic emission calm period when the peak load is 54.89%, and the saturated granite is about 89.87% of the peak load. AE event rate is small and constant, the AE energy rate is high, the AE event rate increases during the calm period after saturated water, AE energy rate decreases; entropy value of acoustic emission waveform signal is 1.5 ~ 2.5 during dry period of granite, saturated granite 0.5 ~ 1.5. Saturated water changes the microscopic rupture mode of granite, which provides a theoretical basis for how water affects the acoustic emission characteristics of rock. The experimental results have enriched the understanding of rock acoustic emission calm period, which is of great significance for the identification of precursors in rock burst acoustic emission monitoring.