基于颗粒流理论的煤与瓦斯突出数值模拟研究

Numerical Simulation of Coal and Gas Outburst Based on Particle Flow Theory

针对煤与瓦斯突出机理的复杂性,基于颗粒流离散元理论,利用PFC3D(particle flow code)软件对煤体进行340组单轴压缩及巴西劈裂试验,建立了煤体宏观参数与颗粒流数值模拟所需细观参数之间的关系。基于寺河矿煤样单轴压缩和抗拉物理实验的实测宏观参数,推算出模拟煤与瓦斯突出所需的细观参数。在PFC3D流固耦合理论的基础上,利用PFC模拟软件进行了煤与瓦斯突出的数值模拟,再现了煤体的堆积过程。研究表明:在突出准备阶段,煤壁深部瓦斯压力较高,突出孔洞附近瓦斯压力梯度较高;发动及发展阶段,平衡状态被破坏,形成口小腔大的突出孔洞,破坏范围由巷道高度的中间位置向顶底板处扩展;在突出过程中,工作面前方煤体靠近煤壁的暴露面处的最大主应力向量逐渐偏离垂直方向,且应力向量连线形成一个凸向煤壁深部的圆弧。

In view of the eomplexity of coal and gas outhurst mechanism and based on the particle flow discrete ele-ment theory, 340 uniaxial compression and Brazilian test wcre conducted on coal by using PFC3D （particle flow code）. The relationship between tie coal＇s macroscopic mechanical parameters and microscopic parameters needed by the particle flow numerical simulation was established. Based on the measured maeroscopie parameters of uniaxial compression and tensile physies experiments on coal sample in Sihe coal mine, the microscopic parameters required by the sinulation of coal and gas outburst. Based on the fluid solid coupling theory of PFC3D, the coal find gas OUt burst numerical simulation was carried out with the help of PFC software and the accumulation process of coal was reproduced, The results show that in the preparatory stage of outburst, the gas pressure in the depth of coal seam is high and the gas pressure gradient near the outburst hole is big. During the launch and development stage, with the break of balanee a small outburst holes with big cavities are formed and the damage expands from the middle to the roof and floor of coal wall. In the outbursting stage, the maximum principal stress vector of the exposed surface of coal in front of the working face gradually deviates from the vertieal direction, and the stress vector attachment forma deep circular arc convex to the coal wall.