岩石声发射定位技术及其实验验证

Experimental verification of rock locating technique with acoustic emission

岩石是典型的非均匀脆性材料,其内部富含各种缺陷(微裂纹、空隙、节理裂隙等),在受载破裂过程中会产生大量的声发射信号。对含不同预制裂纹及完整岩样进行单轴压缩实验,应用声发射仪器及其盖格尔(Geiger)定位算法对岩样破裂过程的裂纹扩展过程进行实验验证。实验结果表明:在单轴压缩加载条件下,含预制裂纹的岩样发生剪切破坏;完整岩样发生劈裂破坏。声发射事件的定位达到较高的精度,很好地反映了岩样内部微裂纹孕育、萌生、繁衍和扩展的三维空间演化模式,不论是含裂纹还是完整试样的声发射定位结果与实际破坏模式非常吻合,这为研究岩石破裂失稳机理提供有力的工具。

Rock was a kind of typical inhomogeneous brittle material abundant in various deficiencies such as microcracks, gaps and joints and would generate a large quantity of acoustic emission signals during damage process under loading. Application of locating techniques with acoustic emission to monitoring rock damage was a good method to study 3D spatial evolutional pattern of microcrack initiation, propagation, expansion and breakthrough during rock failure process. The Geiger locating algorithm was used to verify the locating precision of acoustic emission generated during rock failure. It was shown that the locating precision of acoustic emission would be much better if the Geiger locating algorithm was applied. The rock acoustic emission system was accurate and could monitor the real-time microcrack propagation. The process of the acoustic emission and rock damage were consistent and the locating results could reflect the process of initial, propagation and breakthrough of microcracks accurately. The locating results of the intact specimens and the samples with pre-cracks were in acordance with the real failure pattern of rock, indicating that it was a good tool to study the rock failure mechanism.