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以张双楼矿西一采区生产地质条件为工程背景,基于应力偏量、等效应力、Mises强度准则、能量释放速率分析了煤岩冲击失稳的充要判别准则,揭示了采区煤柱覆岩结构、应力偏量、矿震事件随工作面回采演化规律,并探讨了矿震扰动下采区煤柱冲击危险防治方法.结果表明:煤岩冲击失稳充要条件为开采活动及矿震扰动引起的应力偏量超过煤岩体强度极限,且单位时间内煤岩系统释放弹性能量与矿震应力波输入能量之和大于煤岩系统稳态破坏消耗能量;随着采区工作面持续开采,采区煤柱两侧覆岩形成“T”型悬臂结构并不断损伤破坏;以标量应力偏量第二不变量J2表征应力偏量σ′_(ij),煤柱区应力偏量前期呈“M”型分布并逐渐向单峰型转变,屈服破坏区逐渐向煤柱中部扩展;以矿震频次、能量、震源位置表征应力波扰动σ_(ij)~d,矿震扰动以低能量事件为主,且主要集中于正回采工作面及采区煤柱区域.根据分析结果,提出矿震扰动下采区煤柱切顶爆破、扩大采区煤柱宽度、跨上山开采、大直径钻孔卸压等防冲方法.
Based on the engineering geological conditions of the first mining area in Zhanglianglou Coal Mine, based on the stress bias, equivalent stress, Mises strength criterion and energy release rate, the criterion for determining the impact instability of coal and rock is analyzed, Pillar overburden strata structure, stress offset, and the event of mining with the evolution of working face, and explored the methods to prevent and control the coal pillar impact hazard under mining disturbance.The results show that the necessary and sufficient conditions of coal rock impact instability are the mining activity and The stress deviations caused by the mining disturbance exceed the strength limit of coal and rock mass, and the sum of the energy released by coal rock system and the input energy of the seismic stress wave is larger than the steady-state energy consumption of coal-rock system during the unit time. Continuous mining, mining area on both sides of the coal pillar to form a “T ” type cantilever structure and continuous damage damage; the second invariant of the scalar stress bias J2 characterize the stress bias σ ’_ (ij) The partial deviations were distributed in a “M” shape and gradually shifted to a single peak, and the yield failure zone gradually extended to the middle of coal pillar. The stress wave disturbance σ_ (ij) ~ d and mine location Shock disturbance is dominated by low energy events, and the main set Yuzheng face and coal pillar area of mining area.According to the analysis results, it is proposed that cut-off of coal pillar in mining area with mining-induced disturbance should be widened, and the anti-punching methods such as mining pillar width, cross-mountain mining and large diameter borehole pressure relief should be expanded .