不同开挖步骤引起浅埋隧道地表沉降的数值分析

地铁施工扰动地层,必然造成相应的地层变形。结合沿海地区软土地区浅埋暗挖矩形隧道施工,使用有限元软件对分部开挖进行非线性数值模拟,分析矩形隧道初期支护在开挖过程中的地表沉降变形。分析结果表明,浅埋软土矩形大跨隧道在开挖过程中,群洞效应的作用和施工方案有密切关系,在此基础上提出了控制地层变形的技术措施,在天津地铁1期工程施工中得到了充分的利用并且取得了良好的效果。

ANALYSIS ON THE GROUND DEFORMATION NUMERICAL IMITATES OF SHALLOW TUNNEL IN DIFFERENT EXCAVATION

Because the construction of metro tunnel at shallow depth damages stratum, stratum stress is freed and corresponding deformation is generated, and then the nonlinear mechanical action's stress field and displacement field are studied. With the excavation of littoral tunneling at depth shallow, finite software is adopted to simulate the excavation of tunnel using partial excavation method. Taking Tianjin metro tunnet at depth shallow in inshore area soft weak surround rock for example, the mechanism of rectangular tunnel primary support large deformation process was studied. The law and extend of the influence of these factors on ground surface settlement are presented. The analyze results have showed that the excavating process is a non-liner irreversible process tightly related with in the tunnel surrounding rock and primary support stress and strain. Subsequently, corresponding technologic measures of how to control large deformation in stratum were proposed and fully applied to the construction of Yingkoudao metro station in phase I project. Good effects were achieved in guiding tunnel construction,