不同围压条件下花岗岩压缩破坏声发射特征细观数值模拟
Mesoscopic numerical simulation of acoustic emission experiment in rock compression failure under different confining pressures
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摘要: 采用颗粒流软件PFC2D从细观上对侧限压缩下的非均匀花岗岩岩样进行了声发射(AE)时空特征研究.结果表明,随着围压的增加,岩样破坏的峰值荷载提高,破坏形式由突发失稳逐渐转变为渐进式破坏.岩样声发射的峰值出现时间和岩样的峰值破坏不同步,存在一定的滞后,大约出现在峰后90%峰值荷载处.在岩样破坏前均存在声发射的相对平静期,围压的大小不仅对声发射的时序特征有显著影响,而且声发射相对平静期也随着围压的增加而延长.通过对应变能的追踪,发现在声发射相对平静期存在应变能被吸收的现象,验证了在岩石破坏过程中存在损伤愈合过程.Abstract: The spatial and temporal distributions of acoustic emission(AE) during the deformation of granite samples containing an inhomogeneous fault were studied under confinement using particle flow code software(PFC2D).The results show that with the enhance of confining pressure,failure peak loads of rock samples increase and the failure mode changes from instability to gradual failure.The time asynchrony between AE peak values and ultimate failure in rock samples was found.The former which occurs when the failure load decreases approximately to 90% of its peak value is much later than the latter.Before rock failure there is a relatively quiet period of AE.AE temporal sequence is significantly affected by confining pressure and the relatively quiet period of AE may extend with the confining pressure increase.It is found that the phenomena of strain energy is absorbed during the relatively quiet period of AE through strain energy tracking,validating that damage healing exists in the rock failure process.