浅埋深高强度开采工作面顶板结构时空演化规律研究

    Research on spatial-temporal evolution of roof structure in shallow buried depth high-intensity mining working face

    • 摘要: 为揭示浅埋深高强度开采工作面顶板结构演化规律,以布尔台煤矿12上302工作面为工程背景,综合采用物理相似模拟、多基点位移观测、钻探与钻孔窥视等方法,系统研究了工作面顶板结构的演化过程,揭示了工作面侧向顶板断裂特征,并探讨了临空巷道强烈矿压显现的载荷传递机制。模拟结果表明:在浅埋深高强度开采条件下,顶板断裂演化可划分为悬臂梁、铰接岩梁和短臂“F”形3个阶段;工作面顶板初次垮落步距为40.5 m,周期垮落步距为15.2~27.8 m,平均为18.5 m;高位与中位厚层顶板的覆岩结构由长臂“F”形向短臂“F”形转变;在周期来压阶段,低位厚层顶板呈现悬臂梁结构,而中位和高位厚层顶板则表现为铰接岩梁结构。多基点位移观测显示,工作面的超前影响范围约为57 m;顶板位移经历了缓慢增大、急剧增大和稳定增大3个阶段,分别对应相似模拟试验中的悬臂梁弹性变形、铰接结构滑移失稳以及高位结构压实过程,据此确定了顶板断裂的动态演化过程及其断裂步距。现场实测获得了侧向顶板的断裂结构参数:低位厚层顶板的侧向悬顶长度为13.05 m,中位厚层顶板的侧向悬顶长度约为17.12 m。基于上述研究成果,提出了工程建议:可通过实施“采高动态调控 + 分阶段差异化支护 + 多参量智能预警”的顶板协同控制策略,有效缓解浅埋深高强度开采条件下的强矿压显现,保障巷道围岩稳定性。

       

      Abstract: To reveal the structural evolution law of roof strata in shallow-buried depth working faces with high-intensity mining, this paper takes the 12-upper 302 working face of Buertai Coal Mine as the engineering background. Combined with physical similarity simulation, multi-base displacement observation, drilling and borehole peeping methods, the roof structural evolution process is systematically investigated. The fracture characteristics of lateral roof strata are clarified, and the load transfer mechanism of intense mine pressure behavior in gob-side entry is discussed. The simulation results show that roof fracture evolution under shallow-buried depth high-intensity mining is divided into three stages: cantilever beam, articulated rock beam and short-arm F-shape. The initial caving interval of the working face roof is 40.5 m, and the periodic caving interval ranges from 15.2 m to 27.8 m with an average value of 18.5 m. The overburden structure of middle and upper thick roof strata transforms from long-arm F-shape to short-arm F-shape. During periodic weighting, the lower thick roof presents a cantilever beam structure, while the middle and upper thick roof form articulated rock beam structures. Multi-base displacement observation indicates that the advanced mining influence scope reaches approximately 57 m. Roof displacement undergoes slow increase, sharp increase and stable increase stages, corresponding respectively to elastic deformation of cantilever beam, sliding instability of articulated structure and compaction of high-position structure in simulation tests. The dynamic fracture evolution process and fracture interval of roof strata are determined accordingly. Field measurement obtains lateral roof fracture structural parameters; the lateral hanging roof length of lower thick roof is 13.05 m, and that of middle thick roof is about 17.12 m. Based on the research findings, engineering countermeasures are proposed. The collaborative roof control strategy consisting of “dynamic mining height adjustment, staged differentiated support and multi-parameter intelligent early warning” can effectively mitigate severe mine pressure behavior under shallow buried depth and high-intensity mining.

       

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