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基于切顶短臂梁理论,分析无煤柱切顶自成巷技术原理,结合柠条塔矿施工经验,总结出“支、切、护、封”四步成巷工艺。通过建立联孔聚能爆破力学模型,分析无煤柱自成巷聚能爆破机制,得出联孔爆破损伤贯通判据条件,并结合试验巷道围岩特性,进行聚能切缝关键参数设计。综合运用理论分析、数值模拟及现场实测,对无煤柱自成巷切缝前后工作面和巷道矿压分布规律和演变机制进行系统研究。结果表明,由于切缝结构面切断巷道顶板与工作面顶板岩体间的应力传递路径,改变顶板岩层结构形态,工作面和巷道矿压分布发生明显变化。切缝对工作面矿压影响有一定范围,切缝影响区内周期来压强度有所减小,周期来压步距有所增大。切缝引起的充填结构的支撑作用是造成工作面顶板压力减小的直接原因,来压控制关键层上的有效荷载减小是导致来压步距增大的根本原因。受切缝影响,碎石帮顶板岩体将经历“垮落→压实→稳定”的演变过程,充分利用采空区碎胀矸石的自承载特性和巷道围岩的协同支撑作用,可有效减小支护强度,增强巷道稳定性。
Based on the theory of top-cut short boom, the technical principle of self-forming lane without pillars is analyzed. Based on the construction experience of Tieta Tower, the four-step roadway forming technology of “support, cutting, protection and sealing” is summarized. Through establishing the mechanical model of cohesive blasting, the paper analyzes the mechanism of self-forming blasting without coal pillar and obtains the criterion of penetrating blasting through the perforation. According to the characteristics of the surrounding rock of the test lane, the key parameters of the energy gathering kerf are designed. Comprehensively using theory analysis, numerical simulation and on-site measurement, systematically studied the distribution and evolution mechanism of underground pressure before and after cutting of coal pillar. The results show that due to the kerf structure cut off the stress transfer path between the roof and rock roof, change the rock roof structure morphology, the face and roadway pressure distribution changes obviously. The effect of kerfing on the pressure of face has a certain range, and the influence of kerf on the pressure in the zone decreases, and the pressure step in cycle increases. The supporting effect of the filling structure caused by the kerf is the direct cause of the decrease of the roof pressure on the working face. The reduction of the effective load on the control key layer is the root cause of the increase of the pressure step. Affected by the slits, the gravel-top rock mass will undergo the evolution of “caving → compaction → stability” and make full use of the self-bearing characteristics of the broken-out gangue in the goaf and the synergistic supporting effect of the surrounding rock of the roadway. Effectively reduce the support strength and enhance roadway stability.