超大直径盾构隧道穿越并列布置建筑群影响分析

Influence Analysis of Super-large Diameter Shield Tunnel Passing Through Building Complexes with Parallel Layout

以上海市超大直径盾构隧道北横通道下穿建筑群工程为研究背景,采用数值模拟和现场监测相结合的方法,对隧道穿越过程中建筑沉降进行分析,并在此基础上根据现场建筑排列特点建立并列布置建筑群,通过设计4种不同穿越工况,研究盾构穿越建筑群时地表沉降和隧道上方单幢建筑沉降受周围建筑影响规律。研究结果表明:侧穿区域内建筑对地表沉降曲线影响较小,下穿区域内建筑引起地表沉降曲线呈现非对称“V”形;建筑群对地表沉降主要影响区域为隧道轴线两侧2D范围,施工过程中应对该范围进行重点监测;侧穿区域内建筑对隧道轴线另一侧建筑沉降有抑制作用,下穿区域内的建筑对隧道上方建筑扰动较大;隧道穿越建筑前,纵向方向的建筑群对该建筑的隆起变形有抑制作用,穿越后,纵向方向的建筑群对该建筑的沉降影响更大;建筑纵向倾斜率随盾构开挖进程变化较大,盾构穿越过程中应重点关注建筑纵向倾斜变化。

Based on the super-larger shield tunnel in the project of North-Cross Tunnel in Shanghai passing under building complexes,the settlement of the building caused by the construction of tunnel is analyzed by the methods of numerical simulation and field monitoring,and on this basis,a parallel layout of building complexes is established according to the characteristics of building layout on the site.By comparing four different crossing conditions,the settlement of the ground and the single building influenced by the surrounding buildings when the shield crossed the building complexes were analyzed.The result show that the buildings in the side-passed area have little influence on the surface settlement curve,while the buildings in the under-passed area cause the surface settlement curve to present an asymmetric “V” shape.The main influence area of surface settlement caused by different buildings is 2D range on both sides of the tunnel axis,which should be monitored during the construction.Buildings in the side-passed area limit the settlement of building on the other side of tunnel axis,and the underpass area buildings have an obvious influence on the other buildings settlement.Before the tunnel passes through the building,the longitudinal direction of the building complexes have a suppressive effect on the uplift deformation of this building,and after the tunnel passes through,the longitudinal direction of the building complexes have a greater influence on the settlement of this building.The longitudinal inclination rate varies greatly with the progress of shield construction.During the crossing construction,the longitudinal inclination of the building should be focused on.