单轴压缩下横观各向同性岩石破裂过程声发射特性的离散元模拟

DEM Simulation of Acoustic Emission Characteristics in the Failure Process of Transversely Isotropic Rocks Under Uniaxial Compression

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2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。随着层面倾角的增大,岩石的单轴抗压强度和弹性模量呈先减小后增大,层面倾角90°时的强度甚至超过了0°时的强度。

A research has been conducted, with the discrete element method introduced, on the failure process under uniaxial compression and the acoustic emission characteristics of transversely isotropic rocks with different orientation angles. The experimental results show that the difference in orientation angle of transversely isotropic rocks results in various acoustic emission characteristics. A coupling relation has been found between acoustic emission characteristics and the corresponding stresses, with the spatial response of acoustic emissions occurring mainly at the interface of two kinds of rocks. Differences between mechanical properties of transversely isotropic rocks result in a stress concentration at the interface of inter-stratified rock mass where a crack initiation may first occur, which expands into the nearby area and then causes macroscopic cracks to form, finally resulting in the total failure of the entire specimen. With the increase of orientation angles, the uniaxial compression strength and modulus of elasticity decrease initially and then increase. The compression strength reaches its peak when =90°, where it exceeds the corresponding compression strength when =0°.