基于声发射监测的巴西盘试样破裂过程

Acoustic Emission Monitoring for Failure Process of Brazilian Disc Samples

应用声发射及盖格尔定位算法,实验研究了不同巴西盘岩样加载破裂失稳过程.结果表明:声发射事件主要由于裂纹扩展产生,在初始加载阶段直至裂纹萌生之前,其声发射活动不是很明显;一旦岩样出现初始裂纹,在相应的应力点声发射事件明显增多;在微裂纹扩展的非稳定阶段至岩石破坏瞬间,声发射活动变得异常活跃,声发射事件变化率最大.由此直观反映了巴西盘试验过程初始裂纹的产生、扩展空间位置及扩展方向,即大部分试样的破坏是从一加载端开始,而少数试样的初始裂纹是在岩样的内部产生.同时,声发射事件定位也是岩样内部应力场演化过程的宏观表现,这对于深入研究岩石破裂失稳机制很有意义.

The acoustic emission（AE） and Geiger location algorithm were used to experimentally investigate failure process of different Brazilian disc samples under loading conditions.The results showed that AE events are mainly resulting from the propagation of crack.In the period beginning with loading up to crack initiating the AE activities are unobvious,but the AE events increase obviously once the initial crack occurs at the relevant stress monitoring point.Then,the microcracks are propagated unstably more and more,until finally the rock fails,and in such a period the AE activities increase unusually,i.e.,AE events come up to its highest rate of change.Therefore,the experiments visually showed the occurrence of initial crack in samples and propagating space/orientation.For most of the samples failure begins from a loading position,and for the rest the initial crack occurs within the samples.Moreover,the location of AE events reflects the macro-evolution of the interior stress field,which is of significance to the investigation on the destabilization mechanism of rock failure.