Chongqing Research Institute, China Coal Technology and Engineering Group, Chongqing ,China

为解决高突煤层快速掘进及安全高效回采问题，提出沿工作面走向布置底抽巷，利用超高压水力割缝增透技术预抽煤巷条带瓦斯，同时用作回采期间Y型通风方式的回风巷。采用底板滑移线场理论计算、FLAC3D数值模拟计算底板破坏深度，确定底抽巷的层位距离4号煤层底板约14 m；数值模拟巷道开挖扰动应力集中区在两帮5 m范围内，避免巷道应力集中区叠加，界定了底抽巷布置范围，其后建立每排钻孔总长度表达式，并进行最优解求解为125 m，最终确定水平距离轨道巷约10 m。结果表明：底抽巷水力割缝卸压增透实现轨道巷条带15 d抽采达标；回采期间底抽巷和运输巷顶底板变形量分别在约20 cm和15 cm后基本稳定，保障了工作面安全高效回采。

In order to solve the rapid heading and safe and high efficient mining in the high gassy-outburst seam of Xintian Coal Mine, a floor gas drainage gateway headed along strike direction of the coal mining face was provided. An ultra high hydraulic slotting and permeability improved technology was applied to the gas pre-drainage along the seam gateway. Meanwhile,during the mining period, the seam gateway could be applied as an air return gateway with a Y type ventilation mode. The theoretical calculation of the floor slip line field and the FLAC3D numerical simulation were applied to calculate the floor failure depth and to determine the layer location of the floor gas drainage gateway with a distance of about 14 m to the floor of No.4 seam. The excavation disturbance stress concentration zones of the numerical simulation gateway were within a 5 m scope along the two sidewalls of the gateway. A superposition of the stress concentration zone in the gateway could be avoided. The layout scope of the floor gas drainage gateway was defined. And the total length expression of each borehole raw was established and the best solution was conducted as 125 m. Finally, the horizontal distance to the transportation gateway was determined as about 10 m. The results showed that the hydraulic slotting, pressure released and permeability improvement of the floor gas drainage gateway could realize the 15 days gas drainage target of the transportation gateway. The deformation volume of the roof and floor in the floor gas drainage gateway were about 20 cm and 15 cm and late the gateways were stabilized. Thus，a safety and high efficient mining of the coal mining face could be ensured.