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为研究大同矿区特厚煤层采出空间大和远距离侏罗系煤层群重叠煤柱共同作用下的强矿压显现机制,采用通用离散元程序(UDEC)数值模拟方法,分析重叠煤柱作用下的工作面采动应力规律。应用高精度微震监测技术,得到侏罗系煤层群开采影响下的综放工作面覆岩运动与矿压显现的关系。研究表明,工作面回采至侏罗系煤柱对应区域时,工作面超前支承压力比在非煤柱区域提高了25%~33%;侏罗系煤柱重叠区域,在“煤柱-覆岩联动”和“煤柱-采动应力耦合”共同作用下,工作面矿压显现更为强烈;在临近采空区和侏罗系覆岩共同作用下,沿空巷道矿压显现强烈。工作面开采扰动、临近采空区覆岩运动和侏罗系重叠煤柱的耦合作用,是石炭系综放工作面矿压显现剧烈的根本原因。用提出的基于地面钻孔压裂重叠煤柱弱化的强矿压显现顶板控制技术,可削弱重叠煤柱对工作面开采的影响,减轻特厚煤层综放开采采场矿压的显现强度。
In order to study the mechanism of strong pressure on the coal seam under the action of overlapping coal pillars with large coal seam and long distance Jurassic coal seams in the extra-thick coal seam of Datong mine, a universal discrete element program (UDEC) numerical simulation method was used to analyze the effects of Face mining stress law. The application of high-precision microseismic monitoring technology to get the relationship between the overlying strata movement and the occurrence of mine pressure under the influence of the mining of the Jurassic coal seams. The research shows that when the working face is dredged to the corresponding area of Jurassic coal pillar, the advance bearing pressure of working face is increased by 25% -33% compared with that in non-coal pillar area. In the overlap area of Jurassic coal pillar, Rock pressure appears more intense under the joint action of “rock linkage” and “coal pillar-mining stress coupling”. Under the joint action of the mined-out area and the Jurassic strata, the underground mine roadway pressure appears strong. The disturbance of working face mining, the coupling of overlying strata movement near the mined-out area and the Jurassic overlapping coal pillar are the fundamental reasons for the drastic underground pressure in the fully mechanized top coal caving mining face. The proposed roof control technology based on the strong mineral pressure weakened by the overlying coal pillar in surface fracturing can weaken the influence of overlapping coal pillar on the mining face and reduce the apparent strength of strata pressure in the fully mechanized top coal caving mining face.