岩爆孕育发生过程中的微震活动规律研究

Space Evolution Regularity of Microseism During the Development of Rockburst

为提高采用微震监测技术预报岩爆的准确率,基于最小耗能原理,通过理论分析,花岗岩室内试验和数值分析等方法,揭示了岩爆的孕育发生机理,提出了岩爆发生的准则,建立了岩爆的孕育发生过程的本构方程,探讨了由声发射频次确定的损伤演化曲线与岩爆的损伤演化曲线之间的关系,揭示了应力、能量积累转移与微震活动空间分布规律之间的内在联系.研究结果表明:岩爆的孕育过程是以损伤耗散为主的储能过程,发生过程是以塑性耗散和弹性能释放为主的能量释放过程;同时满足裂纹扩展完成准则和极限储能准则时发生岩爆;由声发射频次确定的损伤演化曲线与岩爆的损伤演化曲线有很好的一致性;通过监测微震活动空间分布规律可揭示岩爆孕育发生过程中应力和能量分布情况,为建立岩爆预报模型提供依据.

Based on the least energy consumption principle,the method of laboratory test for granite,theoretical and numerical analysis are adopted to improve the accuracy of predicting rockburst induced by microseism.The mechanism of the development of rockburst is revealed and the criterion of rockburst occurrence is proposed.The constitutive equations of the process of rockburst development are established.The relationship between damage evolution curve determined by frequency of acoustic emission（AE） and damage evolution curve of rockburst is studied.The relationships among accumulation and transition of stress,accumulation and transition of energy and distribution of AE activity are analyzed.The result shows that the nature of rockburst development is the progress of energy storage in the form of damage dissipation.The nature of rockburst development is the progress of energy release in the form of plastic energy dissipation and elastic energy release.When both the criterion of crack accomplishment and the criterion of limit energy storage are met,the rockburst occurs.The damage evolution curve determined by frequency of AE is consistent with that of rockburst.According to the monitor results of microseism,the distributions of stress and energy in rockburst development is obtained.The study provides a theoretical basis for rockburst prediction.