深部弱胶结软岩工作面矿压显现规律及巷道围岩控制

    Mining pressure behavior and roadway surrounding rock control in deep weakly cemented soft rock working face

    • 摘要: 为研究深部弱胶结软岩工作面矿压显现规律、巷道围岩破坏特征及稳定性控制方法,以黄陇矿区某典型深部矿井弱胶结软岩工作面为研究对象,综合运用理论分析、FLAC3D与UDEC数值模拟及现场实测的方法,开展区段煤柱合理宽度、采场超前支承压力演化特征和巷道围岩控制技术研究。基于极限平衡理论建立煤柱宽度计算模型,理论确定区段煤柱合理宽度为7.84~9.05 m。FLAC3D模拟结果显示,13207工作面和13205工作面回采过程中,受工作面采矿地质条件影响,13205工作面超前支承压力峰值达47.8 MPa,应力集中系数最大2.39,明显高于13207工作面。UDEC数值模拟结果显示,原支护方案下巷道顶底板、左右帮变形量依次为282.3 mm、44.3 mm、221.7 mm、81.0 mm,顶底板移近量累计326.6 mm,左右帮移近量累计302.7 mm,断面收缩率为13.6%,具有一定的围岩控制效果。针对二次采动影响及原支护方案下巷道围岩非对称变形突出问题,提出非对称优化支护方案。UDEC模拟结果显示,优化支护方案下巷道顶底板、左右帮变形量依次为177.6 mm、29.7 mm、101.2 mm、54.2 mm,顶底板移近量累计207.3 mm,左右帮移近量累计155.4 mm,较原支护方案分别再降低36.5%和48.7%,断面收缩率小于8%。同时,现场实测结果表明,巷道顶板下沉量小于200 mm,两帮移近量小于150 mm,巷道围岩变形得到了有效控制,研究成果可为黄陇矿区弱胶结软岩工作面安全高效回采提供一定借鉴。

       

      Abstract: To investigate the law of mining pressure behavior, the characteristics of roadway surrounding rock failure, and the stability control methods of deep weakly cemented soft rock working faces, a typical deep mine weakly cemented soft rock working face in the Huanglong Mining Area is taken as the research object. By comprehensively adopting the methods of theoretical analysis, FLAC3D and UDEC numerical simulation, and field measurement, this study carries out research on the reasonable width of section coal pillars, the evolution characteristics of advanced abutment pressure in stope, and the surrounding rock control technology of roadways. Based on the limit equilibrium theory, a calculation model for coal pillar width is established, and the reasonable width of the section coal pillar is theoretically determined to be 7.84-9.05 m. The FLAC3D simulation results show that during the mining process of the 13207 and 13205 working faces, affected by the mining geological conditions of the working faces, the peak value of advanced abutment pressure in the 13205 working face reaches 47.8 MPa, with a maximum stress concentration coefficient of 2.39, which is significantly higher than that of the 13207 working face. The UDEC numerical simulation results indicate that under the original support scheme, the deformation values of the roof, floor, left rib, and right rib of the roadway are 282.3 mm, 44.3 mm, 221.7 mm, and 81.0 mm, respectively. The cumulative convergence of the roof and floor is 326.6 mm, the cumulative convergence of the left and right ribs is 302.7 mm, and the section shrinkage rate is 13.6%, indicating a certain control effect on the surrounding rock. Aiming at the prominent problems of asymmetric deformation of roadway surrounding rock under the influence of secondary mining and the original support scheme, an asymmetric optimized support scheme is proposed. The UDEC simulation results show that under the optimized support scheme, the deformation values of the roof, floor, left rib, and right rib of the roadway are 177.6 mm, 29.7 mm, 101.2 mm, and 54.2 mm, respectively. The cumulative convergence of the roof and floor is 207.3 mm, and the cumulative convergence of the left and right ribs is 155.4 mm, which are further reduced by 36.5% and 48.7% compared with the original support scheme, respectively, and the section shrinkage rate is less than 8%. Meanwhile, the field measurement results show that the roof subsidence of the roadway is less than 200 mm, and the convergence of the two ribs is less than 150 mm, indicating that the deformation of the roadway surrounding rock has been effectively controlled. The research results can provide a certain reference for the safe and efficient mining of weakly cemented soft rock working faces in the Huanglong Mining Area.

       

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