针对断层区采掘时冲击矿压频频发生的严峻现状,运用理论分析、实验室试验、数值模拟以及工程实践等方法,研究断层区的冲击机制。主要研究内容及结论如下:(1)建立断层闭锁与解锁滑移的力学模型,理论推导得出上行解锁和下行解锁的判定公式,公式表明断层解锁与断层摩擦强度、断层倾角以及水平应力和垂直应力之比有关。(2)提出断层区断层煤柱型冲击矿压的概念,认为断层煤柱型冲击分为断层活化型冲击、煤柱破坏型冲击和耦合失稳型冲击,并阐释各自的冲击作用机制。(3)分析跃进矿25110工作面20次冲击震源分布规律、冲击影响因素和冲击作用机制,认为大部分冲击为断层滑移、老顶断裂和煤柱破坏诱发的断层煤柱型冲击。(4)从弱化断层滑移和减弱煤柱冲击破坏两方面提出针对25110工作面断层煤柱型冲击矿压的治理措施,现场实践表明,控制工作面推进速度可减少断层活化型冲击,提高巷道支护强度和爆破卸压、大直径钻孔卸压可有效降低冲击矿压灾害。
There are more rock bursts happen when coal mining comes near to the fault area. To solve this severe problem, a research on the burst mechanism in fault area has done by means of theoretical analysis, laboratory experiment, numerical simulation, engineering practice, and other methods. The main research contents and conclusions are as follows: (1) The mechanical model of fault locking and unlocking is established;and by theoretical derivation, the judge formula for up unlocking and down unlocking is obtained. The formula indicates that the fault unlocking is decided by fault friction strength, fault dip angle and the ratio between horizontal stress and vertical stress. (2) The concept of fault-pillar induced rock burst is proposed, and it is classified into three kinds: rock burst induced by fault slide, rock burst induced by coal-pillar failure and rock burst induced by the interaction of fault and coal-pillar. Moreover, the burst mechanisms of the three kinds are explained. (3) The burst source distribution rule, burst influence factors and burst mechanism of the 20 times rock bursts at coalface 25110 in Yuejin coal mine are analyzed~ and it is found that the majority of the rock bursts are fault-pillar induced rock burst resulting from fault slide, main roof failure and fault-pillar failure. (4) From the two aspects of weakening fault slide and coal-pillar burst, some control measures against fault-pillar induced rock burst at coalface 25110 are proposed. The engineering application presents that controlling mining speed can reduce fault slide induced rock burst and rock burst disasters can be reduced effectively by strengthening roadway supporting and releasing pressure through blasting and large diameter drilling.