深部小煤柱沿空布置工作面高强度开采下的防冲管控

Anti-impact control under high-intensity mining of deep small coal pillars arranged along goaf

为了确保纳林河二号煤矿深部小煤柱沿空布置工作面的安全高效回采,通过深入分析3-1煤层上覆岩层关键层结构、见方期间采场出现的高静载、强动载冲击要素后,重点采用地表沉降手段对控制地表沉降的主关键层7的破断问题进行观测,同时采用微震监测系统对控制临空顺槽的近距离的亚关键层1和亚关键层2的破断事件进行监测,形成了“高位防震、低位消冲”的冲击风险管控模式。在10刀/d的高强度开采工程背景下,“高位防震”管控中发现了最大下沉值的移动速度V_(ΔH-max)和最大下沉速率的移动速度V_(V-max)两项关键指标与工作面回采速度基本一致,消除了高位矿震风险。“低位消冲”中发现了近距离岩层破断基本呈现“能频同步”的现象,确保了顶板岩层能量处于均衡平稳的释放状态,为今后类似条件下的冲击地压回采工作面煤矿采空区矿震、冲击风险管控、产能调控提供了一条新的路径。

In order to ensure the safe and efficient mining of the deep small coal pillar along the gob in the No.2 coal mine of Nalinhe,after in-depth analysis of the key layer structure of the overlying strata of coal seam 3-1 and the high static load and strong dynamic load impact factors in the stope during the excavation,the surface subsidence method is mainly used to observe the breaking of the main key layer 7 controlling the surface subsidence.At the same time,the micro earthquake monitoring system is adopted to monitor the breaking events of sub critical layer 1 and sub critical layer 2 that control the short distance of the overhead side-roadway,forming the impact risk control mode of“high-level earthquake prevention and low-level eliminating impact”.Under the background of the high-intensity mining project of 10 cut/D,the two key indexes on the movement speed V_(ΔH-max) of the maximum subsidence value and the moving speed V_(V-max) of the maximum subsidence rate are basically consistent with the mining speed of the working face in the“high-level earthquake prevention”control,eliminating the risk of high-level mine earthquake;The phenomenon of“energy frequency synchronization”was found in the“low level eliminating impact”,which ensured that the energy of the roof rock was released in a balanced and stable state.The study provides a new route for goaf earthquake and burst control and mining capacity adjustment in the mining working face with rock burst under similar conditions.