煤层群上下保护层开采围岩应力时空演化规律及应用研究  

Study on spatial and temporal evolution law of surrounding rock stress in mining of upper and lower protective layers of coal seams group and its application

作　　者：刘军 张宪尚[1,2] 张士岭 LIU Jun;ZHANG Xianshang;ZHANG Shiling(China Coal Technology Engineering Group Chongqing Research Institute,Chongqing 400039,China;State Key Laboratory of Gas Disaster Detecting,Preventing and Emergency Controlling,Chongqing 400039,China)

机构地区：[1]中煤科工集团重庆研究院有限公司,重庆400039 [2]瓦斯灾害监控与应急技术国家重点实验室,重庆400039

出　　处：《中国安全生产科学技术》2023年第6期66-73,共8页Journal of Safety Science and Technology

基　　金：国家自然科学基金青年科学基金项目(52204261)。

摘　　要：为实现煤层群上下保护层开采被保护层卸压瓦斯高效抽采,采用数值模拟方法研究上下保护层开采后围岩应力分布及演化规律,根据卸压范围分布实现卸压瓦斯抽采钻孔精准布置。研究结果表明:上下保护层双重开采,有效降低被保护层的应力,卸压范围增大。下保护层开采后被保护层倾斜上下边界卸压角分别为87°、72°,走向卸压角为63°;上保护层开采后被保护层倾斜上下边界卸压角分别为76°、79°。卸压抽采钻孔瓦斯浓度从卸压前的30%~40%增加到卸压后90%以上,单孔瓦斯流量从卸压前0.03~0.08 m^(3)/min增加到卸压后的1.1~1.85 m^(3)/min,瓦斯纯流量呈现数10倍增加,但工作面推过150 m左右,抽采数据快速降低,卸压瓦斯抽采存在显著的空间和时间效应。研究结果可促进多重保护层开采卸压瓦斯抽采技术发展。In order to realize the efficient extraction of pressure relief gas from the protected layer in the mining of the upper and lower protective layers of coal seams group,the numerical simulation method was used to study the distribution and evolution law of surrounding rock stress after the mining of the upper and lower protective layers.According to the distribution of pressure relief range,the precise arrangement of boreholes for the pressure relief gas extraction was realized.The results showed that the dual mining of the upper and lower protective layers could effectively reduce the stress of the protected layer and expand the pressure relief range.After the mining of lower protective layer,the pressure relief angles of the inclined upper and lower boundaries of the protected layer were 87°and 72°,and the pressure relief angle of the direction was 63°.After the mining of upper protective layer,the pressure relief angles of the inclined upper and lower boundaries of the protected layer were 76°and 79°.The boreholes of pressure relief gas extraction concentration increased from 30%~40% before pressure relief to more than 90%after pressure relief,and the single hole gas flow increased from 0.03~0.08 m^(3)/min before pressure relief to 1.1~1.85 m^(3)/min after pressure relief.The pure flow of gas increased dozens of times,but the working face was pushed over about 150 m,the extraction data decreased rapidly,and there were significant spatial and temporal effect in the pressure relief gas extraction.The results can provide support for promoting the development of pressure relief gas extraction technology for the mining of multiple protective layers.

关 键 词：上下保护层 煤层群 围岩应力 演化规律 卸压抽采 

分 类 号：X936[环境科学与工程—安全科学]