正交下穿施工对上部既有隧道安全的影响研究

本文首先对新建隧道下穿上部既有地铁隧道的类型进行了划分,对此类工程既有隧道的变形特征进行了总结。进而,在假定隧道正交下穿施工引起的地层沉降槽符合高斯曲线、既有隧道与周边地层的变形趋势一致的基础上,基于弹性地基梁模型,推导了计算既有隧道受新建隧道垂直下穿施工影响而产生的纵向沉降曲线表达式、纵向应力计算公式以及既有隧道所能承受的极限沉降表达式。形成了定量评价新建隧道垂直下穿施工对上部既有地铁隧道纵向变形和内力影响的理论计算方法和思路。通过与具体工程实例监测结果的对比分析,上述方法所得计算结果与实测值吻合较好,可以满足工程使用要求,对今后类似工程的设计和施工很有借鉴意义。

Study on Longitudinal Deformation and Internal Forces of Upper Existing Metro Tunnel Caused by Undercrossing Tunneling

This paper summarizes the types of undercrossing tunneling projects, as well as the tunneling-induced deformation of the existing tunnel. It is assumed that the tunneling-induced deformation of the existing tunnel is similar to the ground settlement which accords with the Gaussians equation suggested by Professor Peck. Based on the theory of beam on elastic foundation, a method for analyzing the tunneling-induced longitudinal deformation and stress of the existing metro tunnel is presented, and a formula of the ultimate deformation is also deduced. A theoretical method that can assess the tunneling-induced longitudinal deformation and stress is presented in this paper, and this method has taken the soil-tunnel interaction into account. Compared with the in-site observed deformation data, it can be concluded that the data calculated by the formulas accords well with that of in-site observation. The theoretical method can meet the needs of projects. This paper has great reference value for the design and construction of similar projects in the future