研究目的:新建工程上跨既有铁路隧道施工越来越多,需严格考虑对下方铁路隧道的附加位移、附加应 力、平顺度等多方面影响和施工步的动态作用结果;而理论解是难以考虑复杂地形和施工过程的。结合上杭县北站新区内拟建的新站北路上跨赣龙复线铁路工程,应用三维有限元数值分析，探讨上方公路施工对下方铁路隧道的影响，以指导设计,并为类似工程提供参考。
研究结论:通过基于实际地形条件及隧道衬砌设计的三维模型研究得出：铁路隧道的最大附加位移在1mm左右，最大附加内力为1810 kN*m/m;公路路堑开挖面最大水平位移为41.0mm左右。认为在做好有效施工组织和监控量测的前提下,可保证铁路的运营安全。建议施工中应尽量分段、分区、分层、对称地进行路堑开挖，并根据监测数据进行施工步的适当调整,以进一步降低施工带来的不利影响。
Research purposes: With more and more new highways overpassing the existing railway tunnels，it is necessary to carefully consider the multifaceted influences of the highway on the additional displacement，the additional stress and the regularity of the existing railway tunnel. The dynamic effect of the construction should also be considered. With the theoretical solution, it is difficult to consider the complex terrain and dynamic construction process. Combined with the construction of the highway overpassing the the railway tunnel of the Ganzhou-Longyan Railway in the Xinzhanbei Road in the new district of Shanghang County，the three dimensional finite element was used to analyze the influence of the highway construction on the railway tunnel in order to guide the engineering design and provide the references to the similar projects.
Research conclusions: From the research on the actual terrain condition and the 3D FEM model for the design of the tunnel lining, it was seen the maximum additional displacement of the railway tunnel was about lmm, the maximum additional stress of the tunnel was 1810 kN*m/m and the maximum horizontal displacement of the highway excavation face was about 41.0mm. On the premise of well doing the works of construction organization and monitoring, the safe operation of the railway could be archived. It was also proposed that the excavation could be symmetrically conducted section by section，zone by zone and layer by layer and the appropriate adjustments of the construction procedures could be made according to the monitoring data to further reduce adverse effect on the tunnel.
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