切顶沿空留巷 U+L 型通风采场煤自燃风险判定研究.

In order to explore the risk of spontaneous combustion of coal in the U+L type ventilation air area of the first mining surface along the roof cutting gob-side entry retaining, the engineering background of the 11101 working surface of layer 9-1# in the east area of the Mengxi Checkerboard Well Coal Mine was carried out. Through closed oxygen consumption experiments, it is determined that the oxygen consumption capacity of coal samples is weak, the oxygen consumption rate of coal samples is slow under different oxygen volume fractions, and the suffocation oxygen volume fraction(critical value of coal oxygen consumption)is 15%. The pressure difference and air leakage distribution between the two ends of roof cutting gob-side entry retaining and the working surface were determined by on-site measurement, the oxygen distribution data of the return air side was obtained by the actual measurement of the buried pipe at the site, and a similar simulation experimental bench was built for the roof cutting gob-side entry retaining in the mining area to obtain the leakage movement law of the stope. The characteristics of the leakage and spontaneous combustion oxidation distribution of the goaf area along the empty retention lane of the cut top were explored by CFD simulation, and the 3 areas of the goaf area that may have spontaneous combustion hazard were located near the open eye, close to the 5～10 m along the empty space lane and behind the working surface. Under the conditions of nitrogen injection in the tail lane and grout plugging and leak prevention and fire extinguishing measures along the boundary of the empty lane, the risk of converting the spontaneous combustion mode of the U+L ventilation air area into the spontaneous combustion mode of the U-type ventilation air area can be determined. The maximum width of the spontaneous combustion oxidation belt in the goaf area of the Checkerboard Well Mine is 80 m, the minimum safe propulsion speed is 1.2 m/d, and there is no risk of spontaneous combustion, which provides guidance for the engineering fire prevention. [ABSTRACT FROM AUTHOR]