花岗岩脆性破裂过程的声发射前兆特性及RFPA模拟研究

Study on the Precursors Characteristics of Acoustic Emission and RFPA Simulation in the Process of Brittle Fracture of Granite

以花岗岩为研究对象,进行单轴压缩下岩石脆性破坏声发射试验,并利用RFPA模拟岩石破裂声发射演化特征,得出如下结论:在岩石屈服点或峰值应力附近,声发射振铃累计计数会突然增加,声发射能量出现激增;模拟的声发射活动在显裂纹出现之前,有异常汇聚现象;位移矢量在模型破裂位置出现条带异常混乱现象,而应力矢量形成的条带网络与裂纹扩展趋势保持一致。结果表明模拟声发射累计计数曲线出现异常抬头的时间点晚于模拟荷载曲线出现异常下降的时间点,可作为模型破坏前兆信息。

Taking granite as a research object, the acoustic emission experiments of brittle fracture caused by uniaxial compres- sion loading were carried out, and the evolutionary characteristics of acoustic emission in the process of the rock failure were simulated by RFPA. Thus, there were conclusions obtained as follows. Firstly, the cumulative count of the rock acoustic emis- sion ringing would suddenly increase, and the energy of acoustic emission proliferated at the yield point or near by the peak stress of the rock. Then, the simulated acoustic emission had an anomalous convergence phenomenon before the occurrence of open cracks. Finally, the displacement vector occurred the phenomenon that strip was anomalous and chaotic in the failure posi- tion of the model, but the strip network produced by the stress vector was consistent with the expansive trend of cracks. The results showed that the time that the accumulative count curve of simulated acoustic emission occurred anomalous rise was later than the time that the simulated loading curve occurred anomalous drop, which could be regarded as a destruction precursor of the model.