三轴应力下盐岩声发射特征研究

Study on Acoustic Emission of Rock Salt Under Triaxial Compression

利用MTS815 Flex Test GT岩石力学试验系统和PCI-2声发射(AE)3维定位实时监测系统,开展不同围压下盐岩的三轴压缩声发射定位试验,探讨盐岩轴向加载过程中声发射特征的围压效应。结果表明:盐岩AE定位点多少与振铃计数率大小、能率高低具有良好的一致性。声发射高计数、高能率、定位点集聚段等随围压增加而滞后。低围压下,盐岩发生剪切破坏,高计数、高能率、AE定位点集聚段主要出现在屈服阶段和峰值应力前阶段;高围压下,盐岩呈塑性大变形特征,高计数、高能率、AE定位点集聚段主要在峰值及峰后阶段出现。围压增加,累计计数和定位点的总量呈减少趋势;最大能率和累计能量随围压增加而减小,围压为5 MPa时分别约为30 MPa时的43倍和22倍。

To study the effect of confining pressure on acoustic emission characteristics of rock salt in the process of loading,a series of triaxial compression tests were carried out on MTS815 Flex Test GT rock mechanics test system and PCI-2 acoustic emission( AE) monitoring system under different confining pressures. The results showed that AE locations,counting rate and energy rate had good consistency. High counting rate,high energy rate and the agglomeration of AE locations lagged with the confining pressure increasing. Under low confining pressure,the failure of rock salt was shear failure. High counting rate,high energy rate and the agglomeration of AE locations occurred mainly in the yield stage period. Under high confining pressure,rock salt had the large plastic deformation characteristics. High counting rate,high energy rate and the agglomeration of AE locations occurred mainly in the peak stage and after peak stage.With the increase of confining pressure,the cumulative counts and the quantity of AE locations declined,and the maximum energy rate and total energy decreased with the increase of confining pressure.