唐岳松,孙文超,李增强,等. 冲击地压矿井充填开采工作面采动应力激增与跌落机制[J]. 煤炭学报,2024,49(S1):1−14. doi: 10.13225/j.cnki.jccs.2023.0639
引用本文: 唐岳松,孙文超,李增强,等. 冲击地压矿井充填开采工作面采动应力激增与跌落机制[J]. 煤炭学报,2024,49(S1):1−14. doi: 10.13225/j.cnki.jccs.2023.0639
TANG Yuesong,SUN Wenchao,LI Zengqiang,et al. Mining induced stress surge and drop mechanisms in backfilling panel of a coal burst mine[J]. Journal of China Coal Society,2024,49(S1):1−14. doi: 10.13225/j.cnki.jccs.2023.0639
Citation: TANG Yuesong,SUN Wenchao,LI Zengqiang,et al. Mining induced stress surge and drop mechanisms in backfilling panel of a coal burst mine[J]. Journal of China Coal Society,2024,49(S1):1−14. doi: 10.13225/j.cnki.jccs.2023.0639

冲击地压矿井充填开采工作面采动应力激增与跌落机制

Mining induced stress surge and drop mechanisms in backfilling panel of a coal burst mine

  • 摘要: 高应力、多断层是深部矿井冲击地压灾害频率走高的主要原因,充填开采作为降载减冲的最直接手段,依然无法根除冲击地压灾害的发生。为降低冲击地压对冲击倾向性煤层安全开采的影响,采用现场实测、理论分析和室内试验手段研究深部充填开采条件下采动应力激增与跌落机制,探究坚硬顶板预裂爆破与大直径钻孔协同卸压效果。在高应力、多断层、不等宽煤柱和开采扰动多因素叠加影响下,充填开采工作面采动应力存在集中、激增与跌落现象,集中程度小于2.0,非断层影响区超前采动影响范围达到30 m,断层影响下增加至50 m,断层与煤柱叠加影响下增加至70 m;断层活化和围岩破坏引起应变能瞬间释放,转变为破坏煤岩动能,转换率达到17%;揭示了动载应力波产生原理,动载应力波与静态应力场叠加引起采动应力状态骤变;叠加前后若煤岩始终处于破碎状态,则它呈现压实硬化力学行为,发生应力激增现象;若煤岩由完整过渡至破碎状态,则它呈现脆性松脱力学行为,发生应力跌落现象;若煤岩始终处于完整状态,则它呈现弹性回弹力学行为,发生动载冲击现象。微震监测未发现105 J以上的大能量事件,表明充填体支撑下坚硬顶板未发生大范围破断;断层导致微震事件非对称分布,进风巷侧呈现高频低能分布模式,回风巷侧呈现低频高能分布模式,因此,回风巷发生2次冲击地压监测预警,进风巷发生1次冲击地压监测预警;提出了坚硬顶板爆破预裂与大直径钻孔协同卸压技术,顶板岩层形成了大尺度爆破裂隙,有效控制了应力集中程度和应力增长速度,降低了深部开采冲击地压灾害风险。

     

    Abstract: High stress and multi faults lead to rising burst frequency in deep coal mine. Though backfilling mining serves as the most straightforward method for stress-decreasing and burst-preventing, it fails to eliminate coal burst completely. In order to decrease the influence of coal burst on safety mining of deep-buried seam with bursting liability, stress surge and drop mechanisms emerging in backfilling panel are studied with field measurement, theoretical analysis and laboratory test, and destressing effect of roof pre-blasting and large borehole drilling methods is analyzed. High stress, multi faults, width-changing pillar and mining disturbance leads to the emergence of stress concentration, stress surge and stress drop phenomenon in backfilling panel, but the concentration coefficient is smaller than 2.0. At the normal region, influence range reaches 30 m. It increases to 50 m when fault influence is considered and the value grows to 70 m if both fault and pillar influences are added to the panel. Fault activation and rock failure results in sudden release of strain energy, the mechanisms underlying the transition between strain energy and kinetic energy as well as dynamic stress wave are revealed. Note transition ratio reaches 17%. The superposition between dynamic stress wave and static stress field leads to sudden change in mining induced stress. Surrounding rock presents consolidation hardening behavior if it fails before load superposition, resulting in stress surge. Brittle caving behavior emerges if surrounding rock transits from intact into broken state, leading to stress drop. If surrounding rock still keeps intact after stress superposition, it presents elastic rebound behavior and experiences dynamic load. Large-scale rupture of hard roof is not observed due to supporting effect provided by backfilling materials and thus, microseismic energy associated with single event is smaller than 105 J. But microseicmic events presents asymmetrical distribution due to fault influences. They present high frequency and low energy mode at maingate side while low frequency and high energy mode is observed at tailgate side. As a result, burst monitoring pre-warning happens two times in the latter roadway and one time is observed in the former one. Hard roof pre-blasting and large borehole drilling methods are used to decrease mining-induced stress. Large-scale blasting fractures are formed in roof strata, which control stress concentration degree and stress increase speed effectively. Thus, coal burst danger is significantly decreased in deep mining.

     

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