【摘要】 低位坚硬顶板破断释能引起的强扰动是深部矿井冲击地压灾害的一大诱因。为降低冲击地压对深部开采的影响，以古城煤矿1123充填工作面为工程背景，采用理论分析、室内试验和现场实测等手段研究充填体支撑作用对坚硬顶板运动模式的影响，探究低位坚硬顶板的控制方法。厚顶煤碎胀下沉导致采空区充实率低于80%,大埋深、多断层、不等宽煤柱和临近采空区等因素叠加影响下，充填工作面仍然面临围岩大变形破坏、采动应力集中程度高、顶板强冲击载荷等矿压控制难题。因此，本文构建了充填体支撑作用下坚硬顶板结构力学模型，提出了坚硬顶板下沉曲面预测方法，探究了充实率对沉降曲面形态的控制作用，发现了充填体接顶范围、坚硬顶板内部拉应力与充实率之间的线性和负指数关系。微震监测结果表明：1123工作面能级达到10~4 J的大能量事件仅出现两次，微震事件主要分布于应力集中程度高的底板岩层，坚硬顶板岩层事件急剧减少；充填开采条件下1123工作面直接顶(顶煤)发生大变形破坏，坚硬基本顶及上位岩层以弯曲下沉运动模式为主。充填开采避免了坚硬顶板破断释能形成的动力扰动效应，但无法消除煤层压缩变形引起的应力集中现象。本文提出了一种坚硬顶板预裂爆破卸压方法，一次卸压幅度达到2.0～2.7 MPa,有效降低了静态应力场集中程度；开发了坚硬顶板运动模式的“空区充填-钻孔卸压-预裂爆破”多手段控制技术体系，有效抑制了1123工作面顶板强动载、煤层高静载现象的发生，降低了深部矿井坚硬顶板工作面的冲击地压风险。更多还原

【Abstract】 Strong disturbance induced by the sudden rupture of near-field hard roof serves as one of main influences of rock burst in deep coal mines. In order to migrate the threat of rock burst in deep mining, 1123 longwall panel of Gucheng mine is taken as the project background. The influence of the supporting effect provided by the backfilling body on the movement mode of near-field hard roof, as well as the associated control methods, are investigated and discussed by theoretical analysis, laboratory test and field measurement. The results indicate that the gob-filling ratio is lower than 80% under the quick roof subsidence due to the failure and dilation of thick top coal. As a result, the backfilling mining panel(1123) would still be confronted with strong mining pressure problems, such as the large deformation failure of surrounding rock, the mining-induced stress concentration and the dynamic impact of hard roof. Such problems are attributed to large buried depth, multi-fault structures, width-changed coal pillar and adjacent gob area. In this paper, a plate model is established for hard roof by considering supporting effect of the backfilling body. A prediction method is proposed for the subsidence curve, which is highly sensitive to the backfilling ratio. The linear and negative exponent relationships are identified respectively between the backfilling ratio and the contacting range of hard roof and backfilling body and the tensile stress within the hard roof. Seismic monitoring indicates that only two strong micro-seismic events with energy larger than 10~4 J are observed in 1123 panel. Most of events mainly locate in the floor strata due to high stress concentration degree and the number of events decreases drastically in hard roof strata. Such micro-seismic distribution implies that the immediate roof happens to be large deformation failure while the main hard roof and higher strata presents continuous bending and subsiding movement mode. Backfilling mining can migrate the dynamic disturbance induced by energy release in process of hard roof fracturing, but it fails to relieve large stress concentration in the strongly compressed coal seam. Accordingly, hard roof pre-blasting is utilized to release the high stress, and the destressing magnitude reaches 2.0～2.7 MPa, which effectively decreases the concentration degree of the static stress. The multi-controlling method is developed for the hard roof, including gob backfilling, borehole destressing and roof pre-blasting. The combined method could be applicable to relieve the high static stress and strong dynamic load in 1123 panel, which could reduce rock burst risk degree in deep coal mine underlying the hard roof.更多还原