采动裂隙椭抛带动态演化及煤与甲烷共采

为研究采动覆岩裂隙演化及其中瓦斯的运移规律,通过物理相似模拟及数值模拟发现,煤层开采后采动覆岩裂隙形态可用椭抛带来表征。基于岩层控制关键层理论,建立了考虑采高及第一亚关键层与煤层顶板间距的采动裂隙椭抛带动态演化数学模型。运用环境流体力学,传质学,渗流力学,采动岩体力学等理论,得到采动煤体应力与卸压瓦斯渗流,纵向破断裂隙区瓦斯升浮,以及横向离层裂隙区瓦斯扩散等方程,构建出椭抛带中卸压瓦斯渗流-升浮-扩散综合控制模型。分析了椭抛带卸压瓦斯抽采机理,提出相应的煤与甲烷共采技术。通过山西天池煤矿抽采卸压瓦斯的现场实践,说明采动裂隙椭抛带是卸压瓦斯的储运区,将瓦斯抽采系统布置其中,可取得良好效果。

Dynamic evolution of mining fissure elliptic paraboloid zone and extraction coal and gas

In order to research the laws of fissure evolution and methane migration in overlying strata，the authors found that fissure forms of mining overburden rock after mining can be represented by elliptic paraboloid zone through physical similarity simulation and numerical simulation.Based on key strata theory in strata control，considering mining height and distance from the first sub-key strata to coal seam roof，mathematical model of dynamic evolution of mining fissure elliptic paraboloid zone was established.By using environmental fluid mechanics，mass transfer theory，fluid mechanics，mining rock mechanics，equations of mining coal stress and pressure relief gas seepage，gas floating in longitudinal breaking fissure zone，and gas diffusion in transverse separating layer fissures zone were got，and then comprehensive control model of pressure relief gas seepage-floating-diffusion in elliptic paraboloid zone was built.Analyzing extraction mechanism of pressure relief gas in elliptic paraboloid zone，extraction technology of coal and methane was proposed.Through extracting pressure relief gas in Shanxi Tianchi Coal Mine，we got that mining fissure elliptic paraboloid zone was a storage area of pressure relief gas，where gas drainage system can be placed to achieve a good effect.