渗透压-应力耦合作用下煤体常规三轴试验的颗粒流模拟

为了研究在渗透压-应力耦合作用下围压和瓦斯压力对煤体变形破坏规律的影响，借助PFC2D软件进行了340组抗压及抗拉试验模拟，建立了煤体宏观力学参数与细观参数之间的关系。利用平行黏结模型和推导得出的细观参数，对煤体进行了不同围压和瓦斯压力条件下常规三轴试验的颗粒流模拟，并将模拟结果与物理试验结果进行对比及误差分析，对煤体宏观力学参数的变化规律进行了总结。分析结果表明，经过推导得到的宏细观参数关系，可以控制模拟结果的误差在10%之内，能较好地模拟煤体的力学特征；围压增大时，煤体的抗压强度、残余强度及弹性模量呈增大趋势，泊松比以及煤体的破裂角度变小，与物理试验所得围压对煤体的刚度和强度起增强作用的结论一致；瓦斯压力的升高会导致煤体抗压强度，残余强度及弹性模量减小，泊松比以及煤体破裂角度变大，验证了物理试验中瓦斯压力对煤体强度具有劣化作用的结论。

Simulation of conventional triaxial test on coal under hydro-mechanical coupling by particle flow code

In order to study the deformation and destruction law under hydro-mechanical coupling of coal, the relationship between macroscopic mechanical parameters and microscopic parameters of coal is discussed seriously by compression and tension test numerical simulation with PFC2D. Simulation of conventional triaxial test under different confining pressures and gas pressures are performed on coal with parallel bonded model and the inferred relationship. The comparative error is analyzed between test results and simulated results; and the changing law of coal macroscopic mechanical parameters is summarized. The results show that: The relationship inferred by numerical simulation can simulate the coal mechanical characteristics well and control the error less than 10%. With the improvement of confining pressure, the compressive strength, residual strength and elastic modulus show a trend of increase, and the Poisson’s ratio and the angle of coal fracture decrease, so as to prove that the confining pressure can strengthen the stiffness and strength of coal. That the compressive strength, residual strength and elastic modulus continuously decrease and the Poisson’s ratio and the angle of coal fracture increase with the gas pressure increasing shows the weaken effect on the stiffness and strength of coal.