覆岩离层注浆技术通过压实采空区内的破碎岩体，改变了采空区的流场特性和自燃“三带”的分布情况。为了探讨屯兰矿 22301综采工作面离层注浆件下采空区遗煤自燃风险范围，基于实测和数值模拟相结合的方法，对该工作面采空区内存在的自燃“三带”进行准确划分；并提出了注浆钻孔的空隙率三维数学模型，评估不同注浆钻孔位置对采空区流场的影响。结果表明：修正后的空隙率三维数学模型能更好地反映注浆后采空区的气体流场，其模拟结果与现场实测结果的残差精度提高22%；相比于未注浆情况，离层注浆后采空区受到压实作用，有效抑制采空区自然发火的危险性，并导致工作面漏风风流向上汇聚，使采空区垮落带较高位置的氧气体积分数增加；注浆钻孔的布置参数对采空区流场将产生影响，其影响关联度依次为钻孔间距、钻孔排数、钻孔影响半径。

Overburden separation grout filling (OSGF) technology compacts the fragmented rock mass in the goaf and changes the seepage characteristics and distribution of the “three zones” of spontaneous combustion in the goaf. In order to investigate the range of spontaneous combustion risks of residual coal in the goaf under the OSGF in the 22301 fully-mechanized caving face of the Tunlan Coal Mine, based on a combination of field measurement and numerical simulation, accurate demarcation of the spontaneous combustion “three zones” in the goaf was carried out. A three-dimensional mathematical model of borehole porosity was also proposed to evaluate the influence of different OSGF borehole locations on the goaf airflow field. The results show that the modified three-dimensional mathematical model of porosity can better reflect the gas flow field in the goaf after OSGF, and the residual accuracy of its simulation results is improved by 22% compared with the field measurement. Compared with the situation without OSGF, the danger of natural ignition in the goaf is effectively inhibited due to the compaction effect after OSGF. Meanwhile, the air leakage flow converges upward, resulting in an increase of oxygen concentration at higher positions in the caving zone of the goaf. The layout parameters of grouting holes will have an impact on the flow field of goaf, and the correlation degree is the spacing of holes, the number of holes and the influence radius of holes.