饱水对花岗岩声发射平静期影响的实验研究

Experimental Study on the Effect of Acoustic Emission Quiet Period of Granite with Water-Saturated

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 uniaxial loading acoustic emission test of dry and water saturated granite, combined with the experimental analysis of scanning electron microscope, effect of water on the acoustic emission quiet period before the destruction of granite was study. The results show that dry and water saturated granite has AE quiet period before rock rupture, the load level is 54.89% when dry granite appear AE calm period, and the saturated granite is 89.87%. The AE event of dry granite is small and constant, and energy rate is high in AE calm period, but AE events rate increases and energy rate decreases after saturated. The AE signal waveform entropy of dry granite ranges from 1.5 to 2.5 in calm period, but the range of full water granite is 0.5 ~ 1.5. Water-saturated can change granite microscopic fracture mode, which provides theoretical basis how the water affects the rock acoustic emission characteristics. Experimental results enrich the understanding of acoustic emission calm, which is important for identification precursory phenomena of acoustic emission calm.