含瓦斯煤岩体固-气-热耦合数值分析

摘要

The increased mining depth gives a special prominence to the research into the characteristic and law underlying the multi-factor coupling interaction in coal and rock.The study involves performing numerical calculation, combined with the development of the multiple physical field coupling mathematical model of coal and rock containing gas and using COMSOL software;establishing the physical model by setting certain physical parameters and boundary conditions;and thereby delving further into multiple physical field coupling.The result demonstrates that the a sharp increase occurs in gas concentration in the working face the moment coal wall is exposed, followed by a slow drop over time;an increase in gas pressure following the an increased load is explained by a drop in porosity and permeability due to the increased load;and in the coal and rock of high gas pressure and low permeability, the gas pressure gradient rise is most likely to occur near the excavation surface, contributing to the occurrence of coal and gas outburst.%随着煤矿开采深度的增加,研究煤岩体中多因素相互耦合作用的特点和规律尤为重要.结合所建立的含瓦斯煤岩体的多物理场耦合数学模型,利用COMSOL 软件进行数值求解,通过设定一定的物理参数和边界条件构建物理模型,进行多物理场耦合研究.结果表明:在煤壁刚暴露的瞬间,工作面空间瓦斯浓度急剧增大,但随着时间的推移又慢慢变小.瓦斯压力随着载荷的增大而增大,其原因是孔隙率和渗透率随载荷的增大而降低所导致.在瓦斯压力大、透气性低的煤岩体中,瓦斯压力梯度最容易在掘进面附近区域升高,从而造成煤与瓦斯突出的发生.