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东滩煤矿1306轨道顺槽掘进期间,实体煤帮出现大变形破坏,挤压鼓出严重。采用离散元数值模拟分析了深井综放沿空掘巷掘进期间基本顶断裂位置的变化及围岩应力、位移的演化规律。揭示了实体煤帮大变形破坏机制:沿空掘巷诱发围岩大结构中关键块体的回转沉降,导致基本顶断裂线向实体煤侧转移。顶板结构的变化引起实体煤侧支承压力的显著升高并产生大范围的高应力挤压区,使实体煤侧表现出大变形与强流变的破坏特征。基于对实体煤帮变形破坏机制的分析,提出高强让压长锚索联合锚网的实体煤帮控制技术。数值模拟与现场试验表明,实体煤帮采用破断力为600 kN,让压点为260~300 kN的φ22 mm×6800 mm长锚索加强支护后,水平大变形得到有效控制,实体煤帮变形量控制在300 mm内,保证了巷道在掘进期间的稳定性。
During the tunneling of 1306 orbit of Dongtan Coal Mine, there was a great deformation and failure of the solid coal gangue, which resulted in serious squeezing. The discrete element numerical simulation was used to analyze the variation of the basic roof fracture location and the evolution of surrounding rock stress and displacement during the driving of the fully mechanized top coal caving mining face in deep fully mechanized caving face. The mechanism of large deformation and failure of solid coal gang was revealed: the settlement of key blocks in the surrounding rock mass induced by roadway driving along the gob led to the transfer of the basic roof fracture line to the solid coal side. The change of the roof structure causes the significant increase of bearing pressure on the solid coal side and produces a wide range of high-stress crush zone, so that the solid coal side exhibits large deformation and strong rheological failure characteristics. Based on the analysis of the deformation and failure mechanism of solid coal gang, the control technology of solid coal gangue with high strength and pressured anchor cable combined with anchor net is proposed. The numerical simulation and field tests show that the solid horizontal coal gangue can be effectively controlled by strengthening the support with a φ22 mm × 6800 mm long anchor cable with a breaking force of 600 kN and a pressure point of 260-300 kN. The amount of control within 300 mm, to ensure the stability of roadway during excavation.