深部灰岩劈裂破坏的声发射损伤表征

Acoustic Emission Damage Characterization of Deep Limestone under Brazilian Splitting Load

深入研究深部岩石的损伤破裂信息对于岩体稳定性监测和预警具有重要的指导意义。通过进行深部灰岩巴西圆盘劈裂声发射试验,分析了声发射实测全波形的演化特征,并在信号频域内提取了波形主频,以及在时域内计算了波形特征参数RA-AF值。研究结果表明,利用声发射实测全波形可以将岩石损伤过程划分为微损伤萌生阶段、裂纹扩展阶段和结构破坏阶段。低幅值波形主要表现为连续型特征,高幅值波形则主要表现为突发型特征。声发射频谱结构与岩石的损伤量和损伤程度密切相关,主频的聚类分布特征与岩石的微观和宏观破坏相对应。基于声发射主频的RA-AF分界线有助于促进声发射信号在表征岩石破裂模式方面从定性分析向定量分析的转变。

Research on damage fracture information identification of deep rocks is an important guide for rock stability monitoring and early warning.The evolution characteristics of the measured full waveform of acoustic emission collected from the test were analyzed by conducting acoustic emission tests of deep limestone under Brazilian splitting load.The dominant frequency of the waveform was extracted in the frequency domain of the signal,and the RA-AF values of the characteristic parameters were calculated in the time domain.The results show that the rock damage process can be subdivided into micro-damage initiation stage,crack expansion stage and structural damage stage by the acoustic emission full waveform characteristic.Low-amplitude waveforms are mostly continuous signals,while high-amplitude waveforms are mostly burst signals.The structure of the acoustic emission spectrum is closely related to the amount and degree of damage,and the dominant frequency has the characteristics of clustered distribution,which can correspond to the microscopic and macroscopic damage of the rock.The RA-AF boundary based on the division of the dominant frequency of acoustic emission promotes the transformation of the fracture mode of rock characterized by acoustic emission signals from qualitative analysis to quantitative analysis.