基于岩石变形声发射实验结果讨论岩石失稳的可预测性

Predictability of Rock Steady Failure Based on Result of Experiment of Sound Emission as Rock Distortion

根据室内岩石变形声发射实验结果,计算了声发射序列的地震非均匀度GL值,并以此探讨了岩石破裂失稳的可预测性。在双轴压缩、等速率加载条件下,含障碍体断层、挤压雁列断层和Ⅲ型剪切断层等非连续岩石标本在临近滑动失稳前,声发射活动均出现了显著的均匀—非均匀的状态变化,表现为GL值出现持续大于1的异常变化,GL值异常的位置与破裂成核部位相重合,并与断层走向一致;改变统计窗长、窗内分割数及能级统计下限计算声发射序列的GL值,结果表明,GL值计算结果具有一定的稳定性。综合分析认为,地震非均匀度(GL值)可以较好地刻画岩石失稳前夕因破裂成核导致的声发射活动在时间分布上的状态变化,GL值持续异常是岩石失稳的显著性标志,对预测岩石失稳具有较好的指示意义。

Based on experiment result of sound emission as rock distortion indoors, the earthquake non-uniformity GL value of sound emission sequence is calculated and thus the predictability of rock steady failure is discussed. Under the condition of double axes compressing and equal velocity loading, nearly before slide steady failure of non-continuous rock samples, such as fault con- taining obstacle, compressive en echelon fault and If-model shear fault etc. , all the sound emission activities appear obvious change in state, from uniformity to non-uniformity. It shows that the GL values vary abnormally, which is continuously larger than 1. The location of anomaly of GL value superposes with the position of rupture in core nucleating, with the same strike of the fault. The result indicates that the calculated results of GL value are steady in some degree, no matter the GL values of sound emission sequence are calculated at with different statistic window lengths, division number within the window or lower statistic limit of energy level. It is thought, through synthetic analysis, that earthquake non-uniformity （GL value）can well describe the state change on time distribution of sound emission activities ,caused by rupture in core nucleating, just before steady failure of rock. Continuous anomaly in GL value is a notable indication to rock steady failure and useful for predicting rock steady failure.