峁底煤矿区段煤柱巷道锚网索支护效果与侧压控制技术研究

Research on Support Effect of Anchor Net Cable and Lateral Pressure Control Technology for the Section Coal Pillar Roadways in Maodi Coal Mine

  • 摘要: 针对区段煤柱巷道底鼓量580 mm、两帮变形420 mm、顶板下沉220 mm严重变形破坏问题,基于Mohr-Coulomb本构理论和FLAC3D数值模拟,研究了采动影响下区段煤柱应力分布规律,通过锚杆轴向刚度理论和锚网组合体剪切刚度分析,确定了顶锚杆长度2.4 m、排距1.0 m、棚距1.5 m的最优支护参数。针对扩容剪胀变形和塑性流变问题,提出了U型钢棚底岔角调整、支架规格优化和两帮开孔卸压的组合式侧压控制技术。现场应用3个月后,巷道底鼓量降至210 mm,两帮变形降至165 mm,变形速率由50 mm/d降至8 mm/d,应力集中系数由5.65降至2.85,维修次数减少65%,支护成本节省28.6%,实现了煤柱巷道的长期稳定。

     

    Abstract: In view of the serious deformation and damage problem of heaving floor amount of 580 mm,deformation of two sides of 420 mm,and roof subsidence of 220 mm in the section coal pillar roadway.Based on Mohr-Coulomb constitutive theory and FLAC3D numerical simulation,the stress distribution laws of section coal pillars under mining influence are studied.Through the axial stiffness theory of anchor rods and shear stiffness analysis of anchor net combination bodies,the optimal support parameters for the top anchor rod length of 2.4 m,row spacing of 1.0 m and shed spacing of 1.5 m are determined.Aiming at the problem of expansion,shear dilation,deformation,and plastic rheology,a combined type lateral pressure control technology of adjusting the bottom bifurcation angle of the U-shaped steel shed,optimizing the specification of the bracket and releasing the pressure by opening holes on both sides is proposed.After 3 months of on-site application,the heaving floor amount of the roadway decreases to 210 mm,the deformation of the two sides decreases to 165 mm,the deformation rate decreases from 50 mm/d to 8 mm/d,the stress concentration coefficient decreases from 5.65 to 2.85,the maintenance frequency reduces by 65%,and the support cost saves by 28.6%,which achieves long-term stability of coal pillar roadways.

     

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