褶曲构造区回采工作面冲击危险性分析与防治

    Analysis and prevention of rock burst hazards in fold structure mining faces

    • 摘要: 褶曲构造区回采工作面冲击危险性受到多因素耦合作用。通过对鲍店煤矿褶曲构造区7304工作面及其相邻的7302和73上11工作面微震监测预警信息进行分析并相互验证能够及时发现诱因并化解冲击风险。针对7304工作面回采过程中的应力增幅预警,运用7302、73上11工作面的微震监测数据对7304工作面回采掘进的冲击地压前兆特征加以定量分析,研究煤体应力异常增高导致冲击危险性增强的原因。研究结果表明:厚层坚硬顶板、相邻工作面开采扰动、褶曲构造、开采技术条件等各因素对工作面应力增幅异常存在不同程度的影响,微震事件的数量、频次和定位信息能够反映不同因素的作用范围和影响程度;结合7302与7304工作面微震事件平面分布规律,发现七采区西翼工作面受背斜构造轴部区域影响明显,微震事件明显上升,最大日总能量2.48×105 J,褶曲构造背斜轴部区域的高水平应力和其与采动活动的相互作用是导致工作面应力增幅预警的主要控制因素;针对褶曲构造区条件,工作面推进速度保持在5刀/d(约4.0 m/d),开采强度较大,最大日平均总能量达到1.1×105 J。根据7304工作面的旋转开采布置特点及背斜地质构造特征,针对褶曲构造区背斜区域采取迎头卸压与两帮卸压的大直径钻孔卸压技术和加强支护协同控制技术以降低冲击危险。

       

      Abstract: The impact risk of the mining face in the fold structure construction area is often subject to the coupling effects of multiple factors. By analyzing and mutually verifying the micro-seismic monitoring and early warning information of the 7304 working face and its adjacent 7302 and 73 upper 11 working faces in the folded structure area of Baodian Coal Mine, the causes can be discovered in time and the impact risks can be defused. For the early warning of stress increase during the mining process of the 7304 working face, the micro-seismic monitoring data of the 7302 and 73 upper 11 working faces were used to quantitatively analyze the precurential characteristics of rock burst during the mining and tunneling of the 7304 working face, and to study the reasons for the abnormal increase in coal body stress resulting in the enhanced risk of rock burst. The research finds that various factors such as thick-layer hard roof, mining disturbance of adjacent working faces, folded structure, and mining technical conditions have different degrees of influence on the abnormal stress increase of the working face. The number, frequency and location information of micro-seismic events can reflect the action range and influence degree of different factors. Combining the planar distribution laws of micro-seismic events in the 7302 and 7304 working faces, it is found that the working face on the west wing of the seventh mining area is significantly affected by the axial area of anticline structure, and the micro-seismic events increase significantly. The maximum daily total energy is 2.48×105 J. The high-level stress in the axial region of the folded structure anticline and its interaction with mining activities are the main controlling factors leading to the early warning of stress increase in the working face. For the fold structure zone conditions, the advancement speed of the working face is maintained at 5 cuts /d(approximately 4.0 m/d), the mining intensity is relatively high, and the maximum daily average total energy reaches 1.1×105 J. According to the rotational mining layout characteristics of the 7304 working face and the geological structure features of the anticline, for the anticline area in the folded structure zone, the large-diameter borehole pressure relief technology of head pressure relief and two-sided pressure relief, as well as the coordinated control technology of strengthened support, are adopted to reduce the risk of impact.

       

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