地铁超深竖井及超小曲率半径隧道施工技术

以北京地铁3号线东四十条站改扩建施工为背景,阐述了复杂城市环境下超深地铁竖井、深埋大断面马头门及超小曲率半径曲线形隧道的施工技术方案,运用FLAC3D对该方案下的地表沉降及支护结构应力-应变规律进行研究,并与现场检测数据进行对比.结果表明:施工引起的地表沉降控制效果较好,地表沉降影响范围基本控制在竖井井口5m之内;施工过程中竖井井壁支护结构的水平收敛变形量、拉应力和剪应力值均会随着马头门施工的进行而不断增大,但施工结束后井壁结构的变形及应力仍然控制在设计范围内.模拟结果与监测数据基本吻合,研究成果可为今后此类工程提供一定的参考.

Research on the Construction of Ultra-Deep Subway Shaftand Small Curvature Radius Tunnel

This paper takes the reconstruction of Dongsishitiao Station of Beijing Metro Line 3 as the background, the key technologies for the construction of ultra-deep subway shafts, large-section tunnel portal which is deep-buried and curved tunnels with ultra-small radius in complex urban environments are described. FLAC3D is used to study the ground settlement and the mechanical rule of the supporting structure under the above construction plan. Results show that: the ground settlement caused by construction is controlled excellently, and the influence range of ground settlement is basically controlled within 5m from the wellhead; during the construction process, the horizontal convergence, the tensile stress and the shear stress in supporting structure of the shaft wall will increase continuously with the construction progresses, but they are all controlled within the design range after the construction is completed. The simulation results are basically consistent with the monitoring data, and the research results can provide a certain reference for similar projects in the future.