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井下采空区对主斜井稳定性影响研究

Influence of underground goafs on main inclined shaft stability

  • 摘要: 随着矿山开采向深部持续进行,浅部未治理采空区可能对矿山重要井巷工程构成潜在安全威胁,直接影响矿山现有工程设施的利旧,增加投资成本。为充分利旧某矿山主斜井,采用基于倾斜摄影测量技术的工程地质调查、岩体质量分级、扩展Mathews稳定性图解法及数值模拟等多种手段,系统分析了主斜井保安矿柱范围内采空区的稳定性及其对主斜井的安全影响,并给出治理措施。研究结果表明:1号采空区已超过极限跨度,塌落概率约10 %;2~4号采空区整体稳定性较好,仅存在轻微破坏概率,塌落概率为0,但2号采空区位于主斜井正下方,一旦塌落将对主斜井的长期安全运行构成显著威胁;数值模拟计算得到采空区围岩最大主应力约15 MPa,顶板最大位移为4.6 mm,塑性区厚度为1~2 m,整体处于稳定状态;主斜井围岩变形计算结果显示,倾斜、曲率和径向变形特征值均低于规范规定的允许临界值,满足安全运行要求。综合稳定性分析结果,鉴于1号和2号采空区存在安全威胁,建议对其实施充填治理,以降低对主斜井的安全风险;对3号和4号采空区采取封堵措施,防止人员误入。经治理后,可满足主斜井利旧安全要求。研究采用了“工程地质调查−岩体质量分级−经验图解法−数值模拟”综合分析过程,从定性与定量2个角度,系统评估了采空区的稳定性及其安全影响。该研究路线可为矿山评价类似工程问题提供方法借鉴。

     

    Abstract: As mining operations continue to extend to greater depths, untreated shallow goafs may pose potential safety threats to important mine shaft and roadway projects, directly affecting the reuse of existing mine infrastructure and increasing investment costs. To facilitate the reuse of an existing main inclined shaft, this study systematically analyzed the stability of goafs within its protective pillar and their effects on shaft safety using engineering geological surveys based on oblique photogrammetry, rock mass quality classification, the extended Mathews stability graph method, and numerical simulation. Corresponding treatment measures were proposed. The results indicate that Goaf No. 1 has exceeded its limiting span, with a collapse probability of approximately 10 %. Goafs Nos. 2−4 exhibit good overall stability, with only a low probability of failure and no predicted probability of collapse. However, Goaf No. 2 is located directly beneath the main inclined shaft, and its collapse would pose a significant threat to the long-term safe operation of the shaft. Numerical simulation shows that the maximum principal stress in the surrounding rock of the goafs is approximately 15 MPa, the maximum roof displacement is 4.6 mm, and the plastic zone is 1−2 m thick, indicating that the goafs are generally stable. Calculations of deformation in the rock surrounding the main inclined shaft show that the characteristic values of tilt, curvature, and radial deformation are all below the permissible limits specified in the relevant standards, thus meeting the requirements for safe operation. Based on the comprehensive stability analysis and the safety threats posed by Goafs Nos. 1 and 2, backfilling of these goafs is recommended to reduce the safety risks to the main inclined shaft. Sealing measures are recommended for Goafs Nos. 3 and 4 to prevent accidental entry. After treatment, the safety requirements for the reuse of the main inclined shaft can be met. This study adopted an integrated analytical procedure combining engineering geological investigation, rock mass quality classification, an empirical graphical method, and numerical simulation to systematically evaluate the stability of the goafs and their effects on shaft safety, both qualitatively and quantitatively. This research approach provides a methodological reference for evaluating similar engineering problems in other mines.

     

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