岩石应力应变全过程的声发射及分形与混沌特征

Acoustic emission,fractal and chaos characters in rock stress-strain procedure

试验研究了岩石应力-应变全过程的声发射特征,得到岩石试件在初始压密和弹性阶段撞击数少、能量低、振幅小、无事件数产生;应变硬化阶段撞击数骤增、能量高、振幅大、有大量事件数产生;应变软化阶段撞击数骤减、能量低、振幅小、有事件产生。因岩石每个变形阶段产生的声发射特征不同,则可以用声发射方法研究岩石的微观损伤演化和预测现场工程岩体的宏观断裂失稳过程。根据岩石声发射损伤三维定位的试验研究结果,其损伤的发展具有分形特征和统计自相似性,且岩石声发射事件数的演化过程可以用触发—生长—触发的链式生长模型来描述,通过事件数可以观察岩石微裂纹的演化过程,且岩石微裂纹的演化可用Logistic方程来描述,因而岩石的损伤演化具有分叉和混沌特征。

All characters of acoustic emission in the procedure of rock stress-strain have been studied experimentally.In initial consolidation and elastic phase,it is found out that hits seldom happens,energy keeps low,amplitude is small and no event is produced.In strain hardening phase,hits instantly increases,energy go up,amplitude enhanced and events happen.In strain softening phase hits decreased,energy became low,amplitude went back small and events happen.Due to the differences among acoustic emission characters in individual rock-transforming phases,acoustic emission method can be used to study micro-damage evolvement and predict macro-destabilization of engineering rockmass on spot.Based on research result of 3D damage localization in rock acoustic emission,the development of damages characterizes in fractal and statistic self-similarity.Besides,the event evolvement in rock acoustic emission can be described with chain growing model： activation-growth-activation.Through event number,the evolvement of tiny cracks in rocks is observed,and described it with Logistic equation logistic.Rock damage evolvement has furcation and chaos characters.