不同抽采条件对采空区煤自燃“三带”的影响研究

Study on the effect of different extraction conditions on“three zones”of coal spontaneous combustion in goaf

为研究建北矿4204工作面高瓦斯煤层不同抽采条件对采空区煤自燃“三带”分布及危险区域的影响,采用理论分析、数值模拟、现场原位观测等方法,利用CFD模拟软件,通过建立钻孔抽采、上隅角埋管抽采方式下的采空区渗流模型,模拟不同抽采条件下采空区氧浓度场分布规律。采用预埋束管监测系统对采空区氧浓度场分布规律进行现场观测,确定了采空区现场煤自燃“三带”的分布情况,并与模拟结果进行了对比分析,结果较为一致。根据工作面实际情况确定了最小安全推进速度,并提出减少遗煤、两隅角封堵、进风侧注氮与回风侧注浆等针对性的防灭火技术措施,可为瓦斯抽采与采空区遗煤自燃耦合治理方案一体化提供指导。

In order to study the influence of different extraction conditions of coal seam with high gas content on“three zones”and dangerous zone of coal spontaneous combustion in goaf of 4204 working face in Jianbei Coal Mine,based on theoretical analysis,numerical simulation,in situ observation and other research methods,by using CFD simulation software,the seepage model of goaf under drilling drainage and upper corner buried pipe drainage was established to simulate the distribution law of oxygen concentration field in goaf under different drainage conditions.The distribution law of oxygen concentration field in goaf was observed by using pre-buried beam tube monitoring system,and the distribution of“three zones”of coal spontaneous combustion in goaf was determined and compared with the simulation results,the results were consistent.According to the actual situation of the working face,the minimum safe propulsion speed was determined,and the corresponding fire prevention and extinguishing technical measures were put forward,such as reducing residual coal,blocking two corners,injecting nitrogen on the inlet side and grouting on the return air side,which provided guidance for the integration of the coupling control scheme of gas extraction and spontaneous combustion of goaf.