不同基坑开挖顺序下地铁变形特性数值分析

Numerical Analysis of Subway Deformation Characteristics under Different Excavation Sequences

为了研究深大基坑开挖对临近地铁变形的影响,以天津某基坑为研究对象,运用PLAXIS3D数值分析软件,模拟分析了三种开挖工况下地铁变形特性。结果表明:深大基坑开挖导致的地铁车站及隧道水平位移大于竖向位移,但竖向位移的不均匀变化是导致车站及隧道开裂的主要原因;不同的卸载路径会导致不同的地铁变形特性,按照由远及近的开挖原则,选择合理的基坑开挖顺序,可以有效地减少地铁变形。

To study the influence of deep excavation on the deformation of adjacent subway, a foundation pit in Tianjin was taken as the object to simulate and analyze the deformation characteristics of subway under three excavation cases with PLAXIS3D numerical analysis software. The result shows that deep excavation causes horizontal displacement of adjacent subway station and tunnel greater than the vertical displacement thereof, but the uneven variation of vertical displacement is the main reason of the cracks at the station and tunnel;different unloading paths will lead to different deformation characteristics of the subway, according to the principle of excavation from far to near, proper selection of excavation sequence to be designed can reduce the deformation effectively.