花岗岩巷道岩爆声发射振铃计数波动规律研究

开展室内岩爆模拟试验,利用声发射仪监测岩爆过程。分析了岩爆过程声发射振铃计数波动变化规律,运用散点数据差分求导的计算方法,提出一个刻画振铃计数波动特征的指标——振铃计数变化率ξ,基于统计学原理,分析了岩爆过程ξ值的异常变化特征,捕捉岩爆发生前兆。研究表明:岩爆发生前声发射振铃计数会连续出现大幅度波动,声发射ξ值超出稳定阶段波动范围。将稳定阶段声发射ξ值波动范围作为岩爆预警阈值ξ₀,提取ξ>ξ₀时声发射信号作为岩爆前兆信息,进行岩爆灾害预警。水平应力越大,岩爆预警阈值ξ₀越大,岩爆前兆响应系数σ越小。

Study on the Wave Characteristics of Acoustic Emission Count in Rock Burst of Granite Tunnel

This paper carried out the rock burst simulation experiment and used acoustic emission to monitor the evolution process of rock burst, and used scatter data difference derivative calculation method to analyze the change rule of acoustic emission count in the process of rock burst evolution. Then an index to characterize was presented, the wave characteristics of acoustic emission count named the change rate of count, ξ. Based on the principle of statistics, the abnormal change of ξ value of rock burst process was analyzed and the precursor of rock burst was captured. The results show acoustic the emission count has significant and continuous fluctuations before rock burst and the acoustic emission exceeds the range of the steady phase. The wave range of the acoustic emission ξ value of the steady phase is used as the threshold of the rock burst warning, ξ₀. The acoustic emission signal which ξ is greater thanξ₀ is used as the precursor information of the rock burst. The horizontal stress is greater, the threshold value ξ₀ is larger and the precursory response coefficient σ is smaller.