大直径盾构隧道穿越建筑物群变形分析与控制措施

Analaysis of Deformation and Its Control Measures for Large-diameter ShieldTunnels Passing under Building Complexes

大直径盾构隧道掘进施工对土体造成扰动,导致地表产生沉降或隆起,继而严重威胁上部建筑物群的结构安全。文章依托某大直径盾构隧道穿越老旧小区密集建筑物群工程,首先利用二维有限元软件计算关键断面房屋的沉降变形,再对比三维有限元软件的计算结果,分析两种计算方法的适用范围;然后基于三维模型探究了不同初期荷载释放率对盾构穿越引起的地表和房屋变形的影响,最后利用Peck公式计算的理论地表沉降数据,梳理初期荷载释放率、地表沉降、地层损失率三者的内部联系并提出了控制变形的相关措施。研究结果表明,初期荷载释放率越小,地表及房屋沉降也越小,对应的地层损失也越小;对于控制地表变形,减小荷载释放率等同于减小地层损失率;初期荷载释放率、地表沉降、地层损失率这三者减小的量值呈线性关系。

The excavation construction of large-diameter shield tunnels would cause disturbance to the soils,resulting in ground settlement or heave,and thus bringing serious threats to the structural safety of the building complexes above.Based on a large-diameter shield tunnel passing under a dense group of building complexes in an old neigh⁃borhood,this paper first calculates the settlement deformation of the houses on key sections through 2D finite ele⁃ment software,and then compares the calculation results with those through 3D finite element software to analyze the applicability of the two calculation methods.Subsequently,on the basis of the 3D model,it studies the effects of different initial load release rates on the ground surface and house deformation caused by the shield tunnel construc⁃tion.Finally,by using the theoretical ground settlement data calculated by the Peck formula,it sorts out the internal correlation among the initial load release rate,the ground settlement,and the ground loss rate,and puts forward rele⁃vant measures to control deformation.The research results show that the smaller the initial load release rate is,the smaller the ground surface and house settlement as well as corresponding ground loss will be.In terms of ground de⁃formation control,the reduction of the load release rate is equivalent to decreasing the ground loss rate,and the de⁃creasing amounts of initial load release rate,ground settlement,and ground loss rate are in a linear correlation.