对称和非对称载荷下声发射特征的数值模拟研究

Numerical simulation research of acoustic emission characteristics under symmetrical and asymmetrical compressive loads

利用自行开发的岩石破裂过程分析RFPA2D系统,研究了对称载荷和非对称载荷下岩样的破坏过程以及破坏过程中所呈现的声发射特征。数值模拟结果演示两种条件下由微破裂诱致宏观破坏的演化过程以及和微破裂相关的声发射事件源的空间分布特征和事件序列特征。数值模拟结果指出,和对称载荷压缩实验相比,两者的最大区别在于在非对称载荷压缩实验中局部的剪切破坏的发生以及一个更加局部化的声发射事件源分布。从物理意义上讲非对称载荷实验提供了在预定破裂路径下研究脆性破坏的方法,从声发射研究方面来说非对称实验比对称实验能更好地观察声发射事件源的局部化。

Failure process and acoustic emission(AE)characteristics accompanied by the failure process of rock specimens under symmetrical and asymmetrical compressive load conditions were simulated by Rock Failure Process Analysis(RFPA 2D )system,which was developed by the authors.The simulated results reflect macroscopic failure evolution process induced by microscopic fracture and the spatial and temporal distribution characteristics of acoustic emissions event hypocenter.Based on the simulated results,it was pointed out that the great difference between two loading scenarios is the occurrence of localized shear rupture plane and a more localized distribution of acoustic emissions event hypocenter.From the physical point of view,the asymmetrical tests represent a new approach in understanding the brittle failure of rock under controlled laboratory conditions with the path of the propagating rupture front known.From the point of AE research,a localization of AE event hypocenter can be better observed in the asymmetrical test than in the symmetrical test.