山地城市隧道开挖对既有建筑物的影响研究

城市浅埋暗挖隧道施工下穿既有建筑物的工程安全问题越来越受到重视。以重庆曾家岩嘉陵江大桥工程南侧主线隧道下穿、侧穿市政府办公楼,邻近戴笠公馆等建筑物为工程背景,通过FLAC3D建立了三维办公楼框架模型、三维地质地层模型和三维曲线连拱隧道模型,对双连拱隧道开挖过程中的邻近建筑物的变形规律及开挖后地表建筑物的变形和受力进行了分析。研究表明:下穿隧道开挖过程中,框架结构桩基的沉降变形值受距隧道轴线的距离及开挖步的影响较大,而水平变形值受开挖步的影响较大,受距隧道轴线距离的影响较小;隧道开挖将使框架结构底部地基梁的轴向力和弯矩发生较大变化,使桩的轴向力略微增加,弯矩略微变化。

Influence of Tunnel Excavation on Existing Buildings in Mountainous City

The safety problem of urban subway tunnel construction under the existing buildings is being paid more and more attention.Based on the main line tunnels of the south side of the Jialing River Bridge in Chongqing,wearing under an office buildings,closing the Dai Li mansion and others,a three-dimensional framework model,a three-dimensional geological formation model and a three-dimensional curved multi-arch tunnel model were established by FLAC3D,to analyze the deformation of the double-arch tunnel after excavation and the deformation of adjacent buildings in the excavation process.The study shows:during tunnel excavation process,the settlement deformation of the pile foundation is influenced by the distance from the tunnel axis and the excavation step,while the horizontal deformation is greatly influenced by excavation step and slightly influenced by the distance from the tunnel axis;Tunnel excavation will cause a large axial force and bending moment variation of the foundation beam at the bottom of the frame structure,slightly increase the axial force of the pile,and slightly affect the bending moment of pile.