盾构穿越既有铁路的地表沉降分析

以天津地铁3号线铁东路站～北站盾构区间隧道为背景,通过现场实测和数值模拟的方法,对盾构施工穿越既有铁路引起的地表沉降规律进行了研究。现场实测数据表明:沿隧道轴线方向不同位置的地表位移变化较大,对于双线隧道施工,后建隧道对先建隧道的土体扰动影响较大。结合现场监测数据及各项施工参数设置,采用ANSYS有限元分析软件对隧道下穿既有铁路的施工过程进行了数值模拟。在此基础上,通过模拟与实测数据的对比分析,总结了盾构隧道施工引起的既有铁路纵向和横向地表沉降规律,为类似工程的设计和施工提供参考依据。

Analysis of Surface Subsidence by Shield Construction Through Existing Railway

Based on a certain section of shield tunnel of line No.3 of Tianjin Metro,the ground surface subsidence caused by the shield construction across the exisiting railway was investigated by the way of site monitoring and numerical simulation.The actual measured data shows that surface displacement at different position along the tunnel axis varies considerably.For the two-lane tunnel construction,the building tunnel has a great impact of soil disturbance on the built tunnel.Combined with the monitoring data and various construction parameters,finite element simulation of the construction process of tunnel going beneath the existing railway was conducted with ANSYS.By comparison with simulation results and experiment data,the regularity of the longitudinal and transverse surface subsidence is summarized,which can provide a reference for the design and construction of similar projects.