深部矿井大变形巷道围岩结构控制与效果评价方法研究

    Study on surrounding rock structure control and effect evaluation method for large-deformation roadways in deep mines

    • 摘要: 以晋城西部矿区某煤矿5309工作面运输巷道为工程背景,旨在构建一套适用于深部软岩巷道的围岩稳定性综合评价体系与支护优化方法,并通过数值模拟与现场监测验证其有效性。首先系统分析了巷道围岩的地质条件与矿压显现特征,明确煤体应力、顶板离层量、两帮移近量与钻粉率指数作为评价巷道稳定性的核心指标。采用熵值法对这4项指标进行客观赋权,其权重分别为0.15、0.40、0.34和0.11,据此建立多指标综合评价模型,并提出“全长锚固高强锚杆+注浆锚索”复合支护方案作为优化措施。通过FLAC3D数值模拟软件建立三维巷道模型,对比分析支护优化前后的围岩位移场、应力场与塑性区分布。模拟结果显示:优化支护后巷道横向位移最大值由0.163 m降至0.132 m,降幅达19.02%;竖向位移最大值由0.096 m降至0.073 m,降幅为23.96%;顶板下沉量降低26.09%,两帮移近量降低18.52%,塑性区范围显著减小,表明支护结构能够有效增强围岩的整体稳定性与自承能力。在现场应用方面,研究制定系统的矿压监测方案,包括煤体应力、顶板离层、两帮移近量与钻粉率指数的周期性监测。监测数据表明:支护优化后顶板离层量最大值由35 mm降至26 mm,降幅25.71%;两帮移近量最大值由185 mm降至96 mm,降幅48.11%;钻粉率指数平均值由2.2 kg/m降至1.43 kg/m,降幅35%。基于熵值法构建的综合评价模型计算显示,巷道稳定性等级由“低”提升至“高”,验证了支护方案的有效性。

       

      Abstract: Taking the transportation roadway of the 5309 working face in a coal mine in the western Jincheng Mining Area as the engineering background, this study aims to construct a comprehensive evaluation system for surrounding rock stability and a support optimization method suitable for deep soft rock roadways, and verify their effectiveness through numerical simulation and on-site monitoring. First, the study systematically analyzed the geological conditions and strata pressure behavior characteristics of the roadway surrounding rock, and identified coal stress, roof separation, rib convergence, and drilling cuttings index as the core indicators for evaluating roadway stability. The entropy weight method was used to objectively assign weights to these four indicators, resulting in weights of 0.15, 0.40, 0.34, and 0.11, respectively. Based on this, a multi-index comprehensive evaluation model was established, and a composite support scheme of “full-length anchored high-strength bolts + grouting anchor cables” was proposed as an optimization measure. A three-dimensional roadway model was established using FLAC3D numerical simulation software to compare and analyze the surrounding rock displacement field, stress field, and plastic zone distribution before and after support optimization. The simulation results show that after optimized support, the maximum lateral displacement of the roadway decreased from 0.163 m to 0.132 m, with a reduction rate of 19.02%; the maximum vertical displacement decreased from 0.096 m to 0.073 m, with a reduction rate of 23.96%; roof subsidence decreased by 26.09%, rib convergence decreased by 18.52%, and the plastic zone range was significantly reduced, indicating that the support structure can effectively enhance the overall stability and self-bearing capacity of the surrounding rock. In terms of on-site application, a systematic strata pressure monitoring scheme was formulated, including periodic monitoring of coal stress, roof separation, rib convergence, and drilling cuttings index. Monitoring data show that after support optimization, the maximum roof separation decreased from 35 mm to 26 mm, with a reduction rate of 25.71%; the maximum rib convergence decreased from 185 mm to 96 mm, with a reduction rate of 48.11%; the average drilling cuttings index decreased from 2.2 kg/m to 1.43 kg/m, with a reduction rate of 35%. Calculations using the comprehensive evaluation model based on the entropy weight method show that the roadway stability level was improved from “low” to “high”, verifying the effectiveness of the support scheme.

       

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