单轴压缩下横观各向同性岩石破裂过程的声发射特性离散元模拟

摘要

This paper presents an investigation into the failure process of transversely isotropic rock with different orientation angles by distinct element method.Resuhs show that the difference in orientation angle of transversely isotropic rock results in various acoustic emission characteristics.Acoustic emission characteristics are related to stress state.Spatial response of acoustic emission occurs mainly at the interface.Due to the composite material properties of transversely isotropic rock,the complex relationship of stress and strain results in the interface becoming the most likely zone where cracks may first initiate and then propagate.The propagation of cracks expands into the nearby area and then causes macro-cracks to be formed,and finally results in the total failure of the entire specimen.Because of the different physical-mechanical properties of transversely isotropic rock,a complex stress state develops near the interface,including stress concentrations.Moreover,the orientation angle induces shear stress near the interface.Therefore,the interface becomes the most probable location of crack initiation and propagation.The initiation locations of cracks and propagation models largely determine the final failure pattern and are often tightly related with the interfaces.%采用离散单元法研究了横观各向同性岩石在不同层面倾角条件下的单轴压缩破坏过程及声发射特性.结果表明:由于层面倾角的变化,导致横观各向同性岩石破裂过程具有不同的声发射特性.声发射特性与应力存在一定的耦合关系.且声发射空间响应集中在两种岩石的交界面上.互层岩体由于层间力学属性不同,极有可能在交界面处引起应力集中,使得在交界面附近裂纹最先萌生,裂纹进一步向交界面两侧岩体中扩展,从而引起宏观裂纹的出现,最终引起岩体的破坏.裂纹的萌生位置和扩展模式直接决定了岩体的最终破裂形态.