高应力破裂岩体地压显现及其控制技术
Ground pressure formation and control technique under high stress fragment rockmass
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摘要: 小官庄铁矿进路开挖以后支护巷道破坏严重,其围岩变形为无收敛变形的情况.为掌握其地压活动规律,应用岩石破裂过程分析系统,并考虑岩石本身的蠕变特性,模拟其采用无底柱分段崩落法进路开挖过程,对进路开挖过程巷道围岩应力变化进行数值分析.结果表明:随着进路开挖,进路会出现片帮、底鼓和顶板下沉等现象;在矿岩接触带出现高应力集中,导致两进路之间的间柱破坏严重,并随着进路开挖应力逐步向新开挖两进路之间的间柱转移;开挖顺序造成边界矿体出现高应力集中,导致边界矿体难采.采用锚网支护技术有效地控制了巷道围岩的变形破坏,确保开采的顺利进行.Abstract: Supporting drifts in Xiaoguanzhuang Iron Mine destroy badly and the deformation of surrounding rock is no convergence deformation after the drifts are excavated. According to this condition, the drift excavation process of sublevel caving without sill pillars was simulated by rock failure process analysis and the stress variation of surrounding rock was analyzed to grasp the law of ground pressure activities in consideration of rock' s creep characteristic. Simulation results indicate that the destruction form of rib spalling, floor heave and roof falling occur when the drifts are excavated. High stress concentration in the ore-rock contact zone leads to severe destruction of pillars between two drifts; with the excavation of drifts, it diverts into surrounding pillars of the newly caved. Because of excavation sequence, high stress concentration occurs in the boundary ores, which leads to difficulty in mining of boundary ores. Bolt-mesh supporting is applied to control the deformation and destruction of drifts, which can ensure mining activities safely and successfully.