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新建盾构隧道施工过程对既有隧道的变形影响研究对既有隧道的保护具有重要的意义。应用复变函数保角映射理论和Schwarz交替法相结合的方法,首先推导浅埋新建盾构隧道施工过程对既有隧道变形影响的解析解,推导过程中考虑了地层初始应力场以及新建隧道施工过程中不同阶段的影响;接着,应用Matlab数学工具,编制了推导的解析解公式的计算程序,计算了新建盾构隧道施工过程中既有隧道的变形。结合上海人民路越江隧道工程的地质条件,分析了新建隧道开挖过程中盾尾注浆和盾尾脱出两个过程对既有隧道变形影响的附加应力及位移。结果表明,既有隧道变形受到两隧道净间距的大小的影响显著,随着净距的减小,既有隧道洞边径向变形急剧增大。新建隧道施工中盾尾脱开导致既有隧道洞顶变形最大,而盾尾注浆导致既有隧道右侧洞腰变形最大。不同洞径和相同埋深时,随着洞径的增大既有隧道受到新建隧道开挖的影响越大。相同洞径和不同埋深下,既有隧道受到新建隧道开挖影响的变化较小。
The research on the influence of the new shield tunnel construction on the deformation of the existing tunnel is of great significance to the protection of the existing tunnel. By using the method of conformal mapping with complex function and Schwarz alternating method, the analytical solution of the influence of the construction process of the shallow shield tunnel on the deformation of the existing tunnel is deduced. The initial stress field of the formation and the construction process of the new tunnel are considered Then, the mathematic tools of Matlab are applied to develop the calculation program of the analytic solution formula, and the deformation of the existing tunnel during the construction of the new shield tunnel is calculated. Combined with the geological conditions of the Shanghai Renmin Road Crossing River Tunnel Project, the additional stresses and displacements on the existing tunnel deformation caused by the two processes of shield tail grouting and shield tail tailing were analyzed. The results show that the deformation of the existing tunnel is significantly affected by the net spacing of the two tunnels. As the clearance distance decreases, the radial deformation of the tunnel tunnel edge increases sharply. In the new tunnel construction, the shield tail is disengaged and the deformation of the existing tunnel roof is the largest, while the shield tail grouting causes the deformation of the existing tunnel tunnel to the maximum on the right side. With different hole diameters and the same depth, the existing tunnels will be more affected by the excavation of the new tunnel as the hole diameter increases. The same tunnel and different depths, the existing tunnel by the new tunnel excavation less affected.