真三轴条件下单裂隙砂岩破坏过程的颗粒流模拟

采用颗粒流程序从细观角度对在真三轴条件下含单裂隙砂岩的裂纹扩展贯通模式、破裂机理展开研究，重点讨论了不同中主应力对单裂隙砂岩裂纹扩展和其力学特性的影响.研究结果表明:在真三轴压缩条件下，中主应力有助于增大含裂隙砂岩的强度，但过高的中主应力会加快裂纹的扩展、贯通，从而形成宏观破裂面;当中主应力的作用方向与裂隙走向垂直时，裂隙岩石的破坏模式为垂直于裂隙走向形成宏观剪切破裂面，含裂隙砂岩在真三轴压缩条件下的破坏主要为伴随拉破坏的剪切破坏机制.

Particle Flow Simulation of Failure Process in Single Fissured Sandstone Under True Tri-axial Compression

A series of numerical simulations were conducted to analyze the crack propagation and failure mechanism of sandstone with an inner single fissure under true tri-axial compression by using the particle flow code. The effects of different intermediate principal stresses on the crack propagation and failure mechanical properties of fissured sandstone are discussed. Results show that under true tri-axial compression， the intermediate principal stress contributes to the increasing of the peak strength of the fissured sandstone， while a higher intermediate principal stress can accelerate the crack propagation thus form macroscopic fracture in the sandstone sample. When the direction of the intermediate principal stress is consistent with the strike of the inner-fissure， a shear fracture can form in the direction of the fissure strike. The failure of the fissured sandstone under true tri-axial compression is mainly the shear failure accompanied by tensile failure.