关键词: 煤层预抽, 残余瓦斯含量, 保护层, 原始瓦斯含量

Abstract: In view of the many factors of coal seam pre-pumping, it is not possible to accurately predict the distribution of residual gas content, based on the theory of coal & rock physical strength to analyze the influence factors of residual gas content distribution, and based on the PingQing coal mine 117802 back-mining work surface as the research object, the residual gas content distribution law and control mechanism under the influence of different factors. The results show that the residual gas content of the back-mining surface is discrete and high-concentration distribution, mainly controlled by the pre-pumping time and combined stress action of mining activities and geological formations, and the residual gas content shows obvious characteristics of the compound stress action area, which decreases regularly from the concentrated stress to the discharge area, in order: narrow coal column concentrated stress, wide coal column concentrated stress , the mining area - coal column area - fault zone co-influence, the extraction area discharge pressure and the mining area - fault zone joint discharge pressure; the residual gas content and the pre-pumping time show a negative correlation, the average value after 2 to 6 months of pre-pumping is greater than 8 m3/t, the average value after the pre-pumping 7 to 10 months is less than 8 m3/t.