深部高应力巷道变形特性与支护时机

Deformation characteristics and support timing of deep high stress roadway

  • 摘要: 岩石的赋存环境及结构特征决定了岩石的强度准则,从而影响围岩的力学特征与变形特性。依托云南某矿山深部接替工程,以岩石强度准则为基础,分析围岩力学及变形特性,对巷道合理二次支护时机进行研究,以降低深部巷道高地应力环境下围岩呈现出的明显流变性能对巷道支护效果的影响。结果表明:以偏差绝对值之和为目标得出广义H-B准则平均拟合偏差mf最小;对摆佐组围岩进行力学及变形特性分析,最大塑性区半径及范围、最大巷道周边位移随围岩应力的增加近似呈线性增加,且随支护阻力增大逐渐减小;原岩应力大于36 MPa时,围岩流变现象显著,围岩应力增至51 MPa时,随支护阻力增加,巷道周边位移降低明显,但收敛变缓;引入蠕变损伤变量,以稳定蠕变速率为判据,得出当前巷道围岩应力41.5 MPa下巷道合理二次支护时机为开挖后133 h。

     

    Abstract: The rock occurrence environment and structural characteristics determine its strength criteria, and affects the mechanical and deformation characteristics of surrounding rock. This paper relies on the deep replacement project of a mine in Yunnan, based on the rock strength criteria, and analyzes the mechanics and deformation characteristics of surrounding rock and the reasonable secondary support time of roadway to decrease the influence of the roadway support effect because of the obvious rheological properties present under high ground stress. The results showed that the min-average simulated deviations mf was generalized H-B criterion which was aimed at the sum of deviation absolute value. The mechanical and deformation characteristics of Baizuo surrounding rock, the maximum plastic area radius and the range were analyzed, the maximum displacement around the roadway approximately linearly increased with the surrounding rock stress, and gradually decreased with the increased support resistance; while the original rock stress was more than 36 MPa, the rheological phenomenon of surrounding rock was obvious, when it reached to 51 MPa, the displacement around roadway obviously decreased with the increased support resistance, but the convergence slowed down; By introducing creep damage variables and criteria of stable creep rate, it was obtained that the reasonable secondary support timing of the roadway under the rock stress of 41.5 MPa is 133 h after excavation.

     

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