仰拱闭合距离对软弱围岩隧道施工变形控制研究

Deformation Control Research on Influence of Inverted Arch Closing Distance in Soft Surrounding Tunnel Construction

针对铁路隧道工程施工安全技术关于仰拱与掌子面的距离在Ⅴ级围岩不得超过40 m的规定,采用MIDAS GTS软件,探讨仰拱闭合与掌子面距离分别为30 m(工况1)和60 m(工况2)时,对隧道施工变形控制的影响。结果表明:仰拱闭合距离缩短,拱降和水平收敛均减小,初期支护的内力减小,围岩的应变减小;仰拱跟进距离减小,围岩的稳定性更好。同时,为隧道现场仰拱施工提供理论指导。

Under the regulation of Railway Tunnel Construction Safety that the distance between inverted arch and tunnel face on the Level V surrounding rock shall not exceed 40 m,the influence on deformation control in tunnel construction has been explored with software MIDAS GTS under the working conditions of 30 m and 60 m distances between inverted arch closure and tunnel face.Results show that when the distance of inverted arch closure is reduced,vault subsidence and horizontal convergence both decrease,the internal force of primary support gets lessened and the strain of the surrounding rock gets weaker; When the inverted arch following distance is reduced,the stability of the surrounding rock is better.This also offers some theoretical direction for the field working of inverted arch tunnel construction.