沟壑地区浅埋煤层采空区煤自燃危险区域研究

Study on Danger Zone of Coal Spontaneous Combustion in Goaf of Shallow Buried Coal Seam in Gully Area

沟壑地区浅埋煤层上覆岩层厚度不均匀,采动影响造成地表开裂形成台阶式下沉趋势,造成地表裂隙漏风,长时间漏风供氧致采空区遗煤自燃氧化条件良好,威胁矿井安全生产。以典型的某矿沟壑地貌浅埋煤层中11B602工作面为研究对象,现场观测地表裂缝发育几何形貌及大尺度漏风裂缝分布特征,并采用数值模拟研究采空区漏风规律,划分煤自燃危险区域。研究表明:工作面对应地表存在拉伸型和开裂型等裂缝,且风流由地表漏向采空区;受地表漏风影响,采空区内整体O_(2)浓度升高,两巷位置O_(2)浓度大于8%,采空区内由地表向两道漏风引起的煤自燃危险区域为进风侧100~151 m、回风侧14~85 m。通过采取井上下综合防治的措施,有效控制了地表漏风和采空区遗煤自燃,保障了工作面的安全生产。

The overlying strata thickness of shallow buried coal seam in the gully area is not uniform,and the mining influence causes the surface cracking to form a stepped subsidence trend,which causes the air leakage of the surface cracks.The long-term air leakage and oxygen supply cause the spontaneous combustion and oxidation conditions of the residual coal in the goaf to be good,which threatens the safe production of the mine.The 11B602 working face in a typical shallow buried coal seam with gully landform in a mine is taken as the research object.The geometric morphology of surface crack development and the distribution characteristics of large-scale air leakage cracks are observed on site,and the air leakage law of goaf is studied by numerical simulation,and the dangerous area of coal spontaneous combustion is divided.The research shows that there are tensile and cracking cracks on the surface of the working face,and the air leakage from the surface to the goaf;affected by surface air leakage,the overall O_(2) concentration in the goaf increases,and the O_(2) concentration in the two lanes is greater than 8%.The coal spontaneous combustion danger zone caused by air leakage from the surface to the two lanes in the goaf is 100-151 m on the inlet side and 14-85 m on the return side.By taking comprehensive prevention and control measures,the surface air leakage and spontaneous combustion of residual coal in goaf are effectively controlled,and the safe production of working face is guaranteed.