井间高位岩层联动诱冲机制及防冲方法初探

Preliminary study on coal bump mechanism induced by co-movement of higher strata and coal bump control method between two mines

  • 摘要: 相邻矿井开采过程中相互扰动明显,冲击地压灾害频发。为研究巨厚砾岩和逆冲断层控制作用下,相邻矿井之间的相邻工作面开采互扰诱发冲击机理以及两工作面冲击地压协同防控方法,以义马矿区耿村煤矿13230工作面和千秋煤矿21121工作面为实际工程背景,对13230工作面回采期间地表沉降变化、冲击显现特征和支架压力特征、21121东部缆车下山钻孔应力特征以及井间区域微震事件高度变化特征和地应力特征展开现场实测分析。 研究表明,井间相邻工作面非同时期开采形成非对称“T”形覆岩空间结构,井间宽煤柱留设和高位巨厚砾岩条件下,该空间结构发生类似杠杆运动的“撬动”现象,即井间率先采空侧高位岩层下沉运动诱发滞后回采工作面高位岩层整体抬升运动;联动效应对滞后回采工作面垂直应力环境产生扰动且扰动范围有限,13230工作面回采初期垂直应力相对较低,断层活化的高水平应力导致煤体发生典型水平滑移式冲击事故,随13230工作面推进距离增大,水平方向冲击的强度与频度明显降低而垂直方向的冲击占比增加;基于工程实测和室内试验结果,提出井间以阻断高位砂砾互层为核心的弱链增耗防冲方法和采空区高强度充填为核心的吸能稳构防冲方法,实现井间工作面冲击地压的协同防控。 随着我国煤矿逐渐转入高强度集约型开采和深部开采,由高位覆岩联动造成的多工作面之间的应力互扰现象将长期存在,旨在弱化覆岩结构体联动效应的防冲方法与技术是未来单一矿井乃至大型矿区大范围多工作面联合防冲的发展趋势。

     

    Abstract: In the mining process of adjacent mines,each other’s disturbance is obvious and coal bump disasters occur frequently. In order to study the mechanism of coal bump induced by mining disturbance between two adjacent working faces in two adjacent mines and the coordinated control method of coal bump in two working faces under the control of huge thick conglomerate and thrust fault,taking the 13230 face of Gengcun Mine and the 21121 face of Qianqiu Mine in Yima mining area as an actual engineering background,this paper analyzes the surface subsidence,coal bump be- havior and support pressure during the 13230 face’s mining operation,the borehole stress of cable-car dip in the east of the 21121 working face,and the height of micro-seismic events and in-situ stress distribution of two mines’ bounda- ry area. The results show that the asymmetric T-shaped spatial structure is formed in the asynchronous mining process of the two faces,under the condition of coal pillar and higher massive conglomerate in the mine-boundary area,which occurs a prying phenomenon similar to the leverage—high-level strata above goaf side induces an overall uplift move- ment of the corresponding strata above later mining side. Co-movement effect of high-level strata disturbs the vertical stress environment of later mining face and the disturbance range is limited. The vertical stress of the 13230 face is rel- atively low at the beginning of mining and high horizontal stress of fault activation causes typical bump accident with the horizontal slip of coal body. As the increase of mining length of the 13230 face,the intensity and frequency of coal bump of horizontal direction decrease obviously but high proportion in vertical direction. Based on the results of engi- neering and laboratory test,the synergistic prevention method of “ chain-weakening and consumption-increasing” with the core of cutting higher sandstone-conglomerate interbedding and the “ energy-absorbing and structure-stabilizing” with the core of high-strength filling in goaf is proposed to achieve the coordinated control of coal bump between two mines. With China’ s coal mines gradually turning into intensive mining and deep mining,the phenomenon of stress disturbance between multiple working faces caused by higher overburden’s co-movement will exist for a long time. The coal bump prevention method and technology aimed at weakening co-movement effect of overburden structure is the development trend of cooperative prevention among multi-working faces in single mine and even large mining area in the future.

     

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