含软弱夹层的层状围岩隧道开挖稳定性分析

Stability Analysis on Excavation of Layered Surrounding Rock Tunnel with Weak Interlayer

针对含软弱夹层的层状围岩隧道施工与运营过程中病害频发等问题,依托海螺峪隧道工程建立了含软弱夹层的层状围岩隧道开挖计算模型,并根据实际工程情况研究了软弱夹层厚度、隧道相对位置关系和层状围岩节理倾角θ对隧道开挖围岩变形的影响。结果表明:所建模型能较好地模拟含软弱夹层地层状围岩隧道开挖围岩力学响应。围岩变形值随着软弱夹层厚度、相对位置关系的变化逐渐增大,而与层状围岩节理倾角的变化呈对称分布,且对称轴接近90°;通过敏感性分析得出,以软弱夹层厚度对隧道围岩变形影响最为显著,其后依次为相对位置关系、节理倾角。

Aiming at the problems of frequent diseases in the construction and operation of layered surrounding rock tunnel with weak interlayers,a calculation model of layered surrounding rock tunnel excavation with weak interlayers was established based on the engineering background of Hailuoyu Tunnel,and the influence of the thickness of weak interlayers,the relation between the relative position of the tunnel and the joint angleθof layered surrounding rock on the deformation of surrounding rock during tunnel excavation was studied according to the actual engineering situation.The results show that the model can simulate the mechanical response of the layered surrounding rock tunnel with weak interlayer,and the deformation value of the surrounding rock increases gradually with the change of the thickness of the weak interlayer and its relative position,and is symmetrically distributed with the change of the joint dip angle of the layered surrounding rock,and the axis of symmetry is close to 90°.The sensitivity analysis shows that the thickness of soft interlayer has the most significant influence on the deformation of tunnel surrounding rock,followed by the relative position and joint dip angle.