岩石破坏声发射与裂纹尺度增长试验研究

选取内蒙古哈不沁铁矿花岗岩为试验对象,进行了岩石单轴压缩声发射试验,研究采用声发射参量预测岩石破坏裂纹尺度增长的可行性。花岗岩的全应力-应变曲线和声发射各参量曲线分析结果表明,应变的逐渐增加加快了岩石内部聚集的弹性变形能的释放,随着弹性变形能的释放,声发射的幅度、振铃计数、能量等越来越频繁地跳跃,当进入岩石破坏阶段时,声发射参量呈现突发性增长。对比分析了在声发射参量下预测裂纹尺度与实测裂纹尺度的相关性,结果表明,径向破坏裂纹尺度是轴向位移的2倍,且预测值与实测值非常吻合,预测的裂纹尺度能够反映岩石的损伤破裂过程,也能够描述岩石应变的发展过程。

Experimental Study on Acoustic Emission and Crack Size Growth for Rock Failure

An acoustic emission testing was performed after uniaxial compression of the granite from Habuxin Iron Mine in Inner Mongolia, for exploring the feasibility of predicting rock failure and crack size growth with acoustic emission parameters. An analysis of the full stress-strain curve of the granite and curves of strain to acoustic emission parameters showed that a gradual increase in strain accelerated the release of elastic deformation energy within the rock. And the release of elastic deformation energy resulted in the amplitude of acoustic emission, ringing count and energy being more and more frequent. At the rock failure stage, there showed sudden increase for all acoustic emission parameters. The difference between the crack size predicted by using acoustic emission and the practical size was analyzed. The results showed that the radical fracture size was 2 times of axial displacement, and the prediction was in coincidence with the practical size. It is concluded that the predicted crack size can reflect the fracture process caused by damage, as well as rock strain development.