被保护松软厚煤层工作面煤自燃危险性分析与防治技术

Risk analysis and control technology of coal spontaneous combustion in the working face of protected soft thick coal seam

随着煤层开采深度逐渐增加,保护层开采成为有效降低被保护煤层瓦斯突出的关键方案,但易造成被保护煤层漏风严重,煤自燃危险性加剧。针对被保护煤层回采工作面采空区煤自燃综合防治问题,通过分析被保护煤层膨胀变形量、裂隙发育情况、采空区蓄热环境、层间立体漏风等危险扰动因素,确定了被保护煤层采空区煤自燃危险区域分布范围;现场采集工作面煤体,通过对煤体自燃产气与放热测试,获得了煤自燃特征参数;制定了自然发火多方位监控分级预警与立体化综合治理双重防治机制;采取了大规模灌浆封堵与凝胶充填密封由“整体”到“局部”的漏风封堵,及采空区危险区域预防性注氮与工作面联合均压防灭火“动静结合”的煤自燃防治措施。数值模拟分析及现场监测结果表明:被保护煤层采空区煤自燃得到有效抑制。

With the gradual increase of coal seam mining depth,the protective seam mining has become a key scheme to effectively reduce coal spontaneous combustion.Aiming at the comprehensive prevention and control of coal spontaneous combustion in the goaf of protected coal seam mining face,the distribution range of coal spontaneous combustion risk area in the goaf of protected coal seam was determined by analyzing the risk disturbance factors such as expansion deformation of protected coal seam,fracture development,thermal storage environment of goaf and interlayer three-dimensional air leakage.The coal body of the working face was collected on site,and the characteristic parameters of coal spontaneous combustion were obtained through the test of gas production and heat release of coal spontaneous combustion.The dual prevention and control mechanism was formulated for multi-directional monitoring,classification and early warning and three-dimensional comprehensive management of spontaneous combustion;the coal spontaneous combustion prevention and control measures by air leakage sealing of large-scale grouting sealing and gel filling sealing from“whole”to“local”,“dynamic and static combination”of preventive nitrogen injection in dangerous areas of goaf and joint pressure equalization and fire extinguishing in working face were adopted.Numerical simulation analysis and field monitoring results showed that the coal spontaneous combustion in goaf of protected coal seam was effectively inhibited.