新建贵广铁路佛山隧道基坑超挖施工数值模拟分析

以新建贵广铁路佛山隧道基坑开挖为背景，结合现场实测数据，借助有限元计算软件Midas GTS分析该隧道桩撑支护段典型断面在正常开挖施工及超挖施工下基坑支护结构内力、水平位移、支撑轴力及地表沉降的差异。分析结果表明，超挖施工将显著地改变支护结构的受力状态及变形情况，增大坑周地表沉降，对基坑变形控制及坑周邻近建筑物产生不利影响。

Numerical Simulation Analysis on Over-break of Foundation Pit for Foshan Tunnel on New Guiyang-Guangzhou Railway

Taking excavation of foundation pit for Foshan Tunnel on the new Guiyang-Guangzhou Railway as the background,combining with the data measured at the site,and depending on finite element calculation software,Midas GTS,the difference of bending moment and horizontal displacement of retaining structure,strut axial force and surface subsidence between the modes of normal and over-break construction at the typical sections of pile-brace retaining structure in the tunnel is analyzed.The result shows that over-break construction mode significantly changes the stress and deformation conditions of retaining structure,as well as magnifies the surface subsidence around the pit.So,it is harmful for the deformation control in the foundation pit engineering and near buildings.