Mesoscopic numerical simulation of acoustic emission experiment in rock compression failure under different confining pressures
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摘要: 采用顆粒流軟件PFC2D從細觀上對側限壓縮下的非均勻花崗巖巖樣進行了聲發射(AE)時空特征研究.結果表明,隨著圍壓的增加,巖樣破壞的峰值荷載提高,破壞形式由突發失穩逐漸轉變為漸進式破壞.巖樣聲發射的峰值出現時間和巖樣的峰值破壞不同步,存在一定的滯后,大約出現在峰后90%峰值荷載處.在巖樣破壞前均存在聲發射的相對平靜期,圍壓的大小不僅對聲發射的時序特征有顯著影響,而且聲發射相對平靜期也隨著圍壓的增加而延長.通過對應變能的追蹤,發現在聲發射相對平靜期存在應變能被吸收的現象,驗證了在巖石破壞過程中存在損傷愈合過程.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.
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Key words:
- granite /
- acoustic emission（AE） /
- rock mechanics /
- failure analysis /
- confining pressure /
- strain energy
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