黄土隧道下穿地表既有建筑物沉降变形控制研究

Research on Settlement Deformation Control of Existing Surface Buildings Underpassed by Loess Tunnel

黄土隧道在施工过程中容易出现较大变形,尤其当黄土隧道下穿地表既有建筑物时,暗挖施工必然会引起地表建筑物的沉降或变形。依托西延高铁赵家塬隧道下穿创新创业基地办公楼工程,运用有限元软件Midas-GTS进行数值模拟,分析隧道开挖、支护过程对办公楼沉降变形的影响。研究表明:在开挖面接近办公楼正下方时,办公楼沉降变形速率逐渐增大;在开挖面到达办公楼正下方时沉降变形速率达到最大,办公楼沉降值约占总沉降值的70%;在隧道穿过办公楼之后,办公楼沉降速率逐渐减小并趋于收敛。与洞内支护结构变形情况对比,办公楼的最大沉降值更接近相应的规范控制标准值,在施工中应加强对办公楼沉降变形的监控量测。

Loess tunnels are prone to large deformation during construction,especially when loess tunnels underpass existing surface buildings,underground excavation construction will inevitably cause settlement or deformation of surface buildings.Relying on the office building project of Innovation and Entrepreneurship Base underpassed by Zhaojiayuan Tunnel of Xi'an-Yan'an HSR,this paper uses the finite element software Midas-GTS for numerical simulation,and analyzes the influence of tunnel excavation and support process on settlement deformation of the office building.The study shows that the settlement deformation rate of the office building gradually increases when the excavation face is close to the position right below the office building;the settlement deformation rate reaches its maximum when the excavation face reaches right below the office building,and the settlement value of the office building accounts for about 70% of the total settlement value;after the tunnel passes through the office building,the settlement rate of the office building gradually decreases and tends to converge.Compared with the deformation of the support structure in the tunnel,the maximum settlement value of the office building is closer to the corresponding specification control standard value.The monitoring and measurement of the settlement deformation of the office building shall be strengthened during construction.