地铁风道近接下穿既有地铁车站引起的结构变形

为保证北京某新建地铁风道工程近接施工安全,借助FLAC3D软件对该风道CRD工法的施工过程进行动态数值模拟。计算模型为地层结构模型,土体材料模型采用摩尔-库仑准则。结果表明:既有地铁车站最大沉降量为2.54 mm,发生在该车站东南出入口及风道结构转接的位置,车站与出入口的连接处最大沉降量为0.63 mm。靠近新建地铁风道开挖一侧的既有车站出入口侧墙最大水平位移为0.49 mm,车站与出入口连接处的纵向最大水平位移为0.28 mm。新建地铁风道工程对既有地铁车站整体结构变形影响较小,既有车站最大沉降量及轨道最大差异沉降值均在安全范围内。该研究为地铁工程的设计与施工提供了有益参考。

Deformation caused by nearby existing subway station with under crossed air duct

Aimed at ensuring the safety of the air duct construction of a newly built subway station in Beijing,this paper introduces the use of FLAC3D to perform the dynamic numerical simulation of CRD method-based construction of subway air duct project.This method involves stratigraphic structure model as the computational model and the soil material model is Mole-Coulomb criterion.The results suggest that the existing station is subject to the largest settlement of 2.54 mm,occurring at the southeast entrance of the station and the transferring location of the air duct structure,leaving the connection place of the station and the entrance exposed to the largest settlement of 0.63 mm,and the entrance side wall near the excavation place of subway air duct is subject to the horizontal displacement of 0.49 mm.The connection place of the station and the entrance experiences the largest horizontal displacement of 0.28 mm.The air duct construction exerts a less effect on the overall deformation of the station structure,keeping both the largest settlement of the existing station and the differential settlement of the track within the safety range.This research offers the useful reference for the design and construction of the subway project.