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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。
In order to study the effect of confining pressure and gas pressure on the deformation and failure of coal under osmotic pressure-stress coupling, 340 sets of compressive and tensile tests were simulated with PFC2D software, and the macroscopic mechanical parameters and mesoscopic parameters The relationship between. By using the parallel bond model and the derived mesoscopic parameters, the particle flow simulation of coal under different confining pressures and conventional triaxial tests under gas pressure was carried out. The simulation results were compared with the physical test results and error analysis was carried out. The macro-mechanical parameters of coal body are summarized. The analysis results show that after the derivation of the relationship between the macro and micro parameters, the error of the simulation results can be controlled within 10%, which can well simulate the mechanical characteristics of coal; when the confining pressure increases, the compressive strength, The residual strength and elastic modulus increase, the Poisson’s ratio and the rupture angle of coal become smaller, which is consistent with the conclusion that the confining pressure in physical experiment enhances the rigidity and strength of coal; the increase of gas pressure will lead to The compressive strength, residual strength and elastic modulus of coal decrease, Poisson’s ratio and coal rupture angle become larger, which proves the conclusion that the gas pressure has a deteriorating effect on the strength of coal in physical experiment.