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采用有限单元法对暗挖平顶直墙结构的过街地道进行施工阶段分析,按照设计施工步骤对分部开挖后的地层沉降及衬砌内力进行分析,并着重探讨施工过程的衬砌结构力学体系转换,并对此类工程进行风险源分析及提出了对应的工程措施。分析结果表明,超浅埋过街地道需通过地层加固措施控制地表沉降以及保证上部既有管线安全;过街地道的开挖能够保证下部地铁隧道的安全;拆除临时支护使得边墙轴力增大约2～3倍,衬砌弯矩增大约4～5倍;开挖进尺以0.5～1.0 m,左右导坑间距以6～8 m为宜。
The finite element method was used to analyze the construction stages of the overpassed tunnels with undercutting and straight-through wall structures. The strata settlement and internal lining force after excavation were analyzed according to the design and construction steps. The mechanical structure transformation of lining structure during construction , And carries on the risk source analysis to this kind of project and puts forward the corresponding engineering measures. The results show that underground tunnels with super-shallow burial need to control surface subsidence through strata reinforcement measures and ensure the safety of the existing upper pipelines. Tunnel excavation can ensure the safety of the lower subway tunnels. The removal of temporary support increases the axial force by about 2 ~ 3 times, the lining bending moment increases about 4 ~ 5 times; excavation footage to 0.5 ~ 1.0 m, left and right guide pit spacing to 6 ~ 8 m is appropriate.