岩石单轴压缩变形场演化的声发射特征研究

 对单轴压缩条件下一种红砂岩试件变形场演化过程中声发射特征进行研究。以数字散斑相关方法进行试件加载全过程的变形场演化观测，利用声发射系统采集试件加载全过程的声发射信号，对岩石变形演化过程中的变形局部化演化、变形局部化带拉伸以及变形局部化带错动对应的声发射特征进行研究，研究结果表明：(1) 由加载曲线与声发射振铃计数、声发射能量演化对应关系可知，应力突降时声发射振铃计数和声发射能量出现激增，但振铃计数激增和声发射能量激增，应力不一定突降；(2) 加载应力与声发射振铃累计计数在演化趋势上具有较好的对应关系，但声发射振铃累计计数增幅与对应的应力降低量值无关；(3) 声发射峰前“平静期”并不代表岩石变形场演化处于平静阶段，此阶段变形局部化带的宽度、长度以及变形量值在不断增加；(4) 变形局部化带的宽度、长度以及变形量值的演化对声发射振铃计数及声发射能量影响很小，变形局部化带的拉伸速率及变形局部化带的滑动速率变化对声发射振铃计数和声发射能量影响较大，其中变形局部化带滑动影响最大。

Acoustic emission characteristics of deformation field development of rock under uniaxial loading

This paper concentrates on the acoustic emission(AE) characteristics of deformation field development of red sandstone under uniaxial compression. The digital speckle correlation method was adopted to measure the deformation field. The AE information was monitored by an AE system during the deformation and failure of the rock. The AE characteristics corresponding to the deformation localization and the stretch and dislocation of localization band were studied. The AE ringing counts and the AE energy increase suddenly when the stress drops abruptly. Sometimes，the stress does not drop abruptly when the AE ringing counts and AE energy increase sharply. There is a close correlation between the AE cumulative ringing counts and loading stress curve during the whole loading process，but the stress drop is not proportional to the increment of AE cumulative ringing counts. The development of rock deformation field may not be in a calm stage during the“quiet period”of AE. The size and value of deformation localization band keep increasing in the“quiet period”of AE. The length，the width and the deformation magnitude of the deformation localization band have little effect on the AE energy and AE ringing counts. The stretching rate and dislocation rate of deformation localization band have a great influence on the AE ringing counts and AE energy，especially the sliding of the deformation localization band has greatest effect.