废弃露天采坑回填对井工巷道稳定性的影响分析  

Analysis on the influence of backfilling of abandoned open-pit on underground roadways stability

作　　者：李凤明[1] 蓝航 韩科明 韩震 LI Fengming;LAN Hang;HAN Keming;HAN Zhen(Land Reclamation&Ecological Restoration Research Institute,China Coal Research Institute,Beijing 100013;Ecological Environment Technology Co.,Ltd.,Beijing 100013,China)

机构地区：[1]煤炭科学研究总院土地整治与生态修复研究院,北京100013 [2]中煤科工生态环境科技有限公司,北京100013

出　　处：《煤炭科学技术》2021年第12期11-19,共9页Coal Science and Technology

摘　　要：为保证高寒高海拔地区露井联合矿区废弃露天采坑回填时和回填后其下方浅埋井工巷道的稳定性,分析了影响巷道稳定性的主要因素,包括:回填体载荷、施工车辆载荷及其动载、采坑积水后水体载荷及地面井下间的水力联系,通过分析采坑纵、横剖面井工巷道和采坑底部的垂直距离,确定了一区段回风斜巷为重点评价对象,圈定了评价范围。分析认为冷季时,冻土层的存在起到了隔水作用;暖季时,虽然存在季节性冻融影响,但地面井下之间的水力联系本身较弱,也不会因为采坑回填而加强。采用弹性力学理论计算了回填体载荷、施工车辆载荷及其动载和采坑蓄水后水体载荷产生的最大附加应力随深度变化值,采用极限平衡理论计算了巷道极限承载的覆岩高度,以最大附加应力达到该点自重应力10%时的深度为附加应力影响深度,通过比较最大附加应力影响深度与巷道极限承载覆岩高度之和与实际覆岩厚度的大小,得出在只考虑回填体载荷和车辆施工载荷条件下,一区段回风斜巷虽能保持整体稳定,但局部安全覆岩厚度不足1 m;考虑采坑积水水体载荷后,一区段回风斜巷起坡点以上60 m范围内巷道将整体处于不稳定状态。根据分析结果,提出了地面减小施工载荷扰动的工艺措施和井下注浆锚索加强支护和监测相结合的巷道保护方法。In order to ensure stability of the shallow underground mine roadway underneath it during and after the backfilling of the abandoned open pit in the open-pit combined mining area in the high-cold and high-altitude area,the main influence factors of roadways stability are analyzed,including:backfill body load,construction vehicle load,water body load and the hydraulic connection of surface to the roadways.By analyzing vertical distance between the vertical and transverse sections of the mining roadway and the bottom of the mining pit,a section of the return air inclined road is determined as the key evaluation object,delineating the scope of evaluation.The analysis suggests that in cold seasons,the existence of the frozen soil layer acts as a water barrier.Although there is a seasonal freezing and thawing effect in warm seasons,the hydraulic connection between the ground and underground is weak and will not be strengthened by the backfill of the pit.The elastic mechanics theory is used to calculate the load of the backfill,the load of the construction vehicle and its dynamic load,and the maximum additional stress caused by the water load after the pit is impounded.The value of the maximum additional stress with the depth is calculated.The depth at which the maximum additional stress reaches 10%of the self-weight stress at this point is the additional stress impact depth.By comparing the sum of the impact depth of the maximum additional stress and the ultimate bearing overburden height of the roadway with the actual overburden thickness,it can be concluded that the return air inclined roadway in No.1 section can maintain the overall stability,but the thickness of the local safety overlying rock is less than 1 m;after considering the water load of the mining pit,the roadway within a range of 60 m above the starting point of the return air inclined roadway will be in an unstable state as a whole.Based on the results,a roadway protection method that combines the technological measures to reduce the disturbance of the

关 键 词：露天采坑 回填 巷道稳定性 附加应力 施工扰动应力 

分 类 号：TD353[矿业工程—矿井建设]