大直径盾构下穿施工对近邻地面构建筑物的影响分析研究

摘要

针对大直径盾构下穿近邻地面设施施工工况, 建立考虑地层-隧道-构筑物相互作用的三维有限元模型, 真实的模拟了盾构施工过程, 系统的分析了盾构掘进对地层和构建筑物的沉降影响、刀盘位置对构建筑物的影响;进一步研究了不同位置桩的桩基承载力受盾构开挖的影响.结果表明:地面及构建筑物的沉降影响主要集中在隧道顶部, 影响宽度约为隧道宽加两倍隧道埋深;刀盘正上方的地层沉降速率最大;受盾构施工影响, 桩顶桩基承载力增大, 桩底桩基承载力减小, 当桩位于隧道正上方时, 桩顶和桩底的桩基承载力的变化最大.所得结论为减小大直径盾构下穿施工对近邻地面构建筑物的影响有一定的指导作用.%Under conditions of large diameter shield tunnel going below of the construction of surface facilities, establish the dimensional finite element model considering Layer-Tunnel-structure interaction, simulate the shield tunnel construction process realistically, systematic analysis of the shield tunneling impact on the settlement of the formation and structure of the building, the cutter location impact on the structure of the building, further study of the pile foundation in different positions of the pile by the influence of shield tunnels. The results show that settlement on the ground and the structure of the building is mainly concentrated in the top of the tunnel, the effect of the width is about tunnel width plus twice the depth of the tunnel; formation sedimentation rate is the maximum when just above cutterhead; affected by the shield tunnel construction, the bearing capacity at the pile top increases, the bearing capacity at the pile bottom decreases, when the pile is located directly above the tunnel, the bearing capacity at pile top and the pile bottom is maximum. The conclusion has a guiding role to reduce the influence that the large diameter shield construction is below of the construction of surface facilities.