煤与瓦斯突出过程的细观机制研究

 煤与瓦斯突出过程是地下煤矿开采中的一个很复杂的动力灾害问题。在综合收集整理国内外煤与瓦斯突出模拟研究基础上，以颗粒法为基础，建立数值模型和模拟过程，对煤与瓦斯突出过程中相关的微裂纹和位移演化、应力和速度场演化、瓦斯压力和颗粒分层刚度比等细观机制进行模拟和研究。研究结果表明：采用颗粒法模拟所得出的煤与瓦斯突出过程是一个相对很快的动力过程，发生的时间极短，煤岩体损伤主要以拉裂纹为主，剪切裂纹主要集中在瓦斯突出前端，而拉裂纹则深入到煤岩体中的更深部位；同时研究认为瓦斯压力对煤岩体损伤有很大影响，当瓦斯压力相对较小时，剪切裂纹主要在分布侵入体前端，而拉裂纹则沿着侵入煤岩体贯入一定的深度。当瓦斯压力相对较大时，剪切裂纹与拉裂纹贯入深度基本一致，且在煤岩体的损伤中，剪切裂纹比例随之增大；最后对模型中的分层刚度比与裂纹分布形态和应力分布进行了研究，当分层刚度比不相同时，其裂纹传播速度和形态都不相同。这些研究对于认识瓦斯突出机制和瓦斯突出防治提供了理论基础。

Study of meso-mechanism of coal and gas outburst

Coal and gas outburst is a very complex dynamic disaster in underground coal mining process. In this paper，a numerical model was established based on the theory of particle flow to simulate the development of micro-cracks，displacement，force and velocity fields，and to investigate the microscopic mechanism of gas pressure and layer-stiffness ratio. The simulation results show that the coal and gas outburst is a relatively quick process. The shear cracks were mainly concentrated in the front tip of outburst，the tensile cracks occurred deep inside the coal. The gas outburst has great influence on the coal and rock damage. When the gas pressure is relatively small，the shear cracks occur at the front and the tensile crack reached deeper. When the gas pressure is relatively large，the shear cracks and tensile cracks penetrate into the same depth. The damage of coal and rock and the shear crack ratio increases. When the layer-stiffness ratios is not the same，the speed and shape of crack propagation are not the same.