明挖隧道施工对并行高铁的影响分析

Impact of a Cut and Cover TunnelConstruction on the Adjacent Nanning-Guangzhou High-Speed Rail

明挖隧道与在建南广高铁近似平行,铁路轨道距隧道基坑边线最近约20.5m,需考虑隧道施工对高铁的影响。首先综合各类规范及现有工程经验,确定安全影响评判标准;其次选取典型支护断面(距离近,基坑深,地质差),采用有限元法模拟隧道施工过程,分析在有无铁路荷载作用两种工况下隧道施工对邻近铁路路基的影响;最后,利用分析结果及评判标准,评价明挖隧道施工时铁路的安全状况。

A segment of cut-and-cover tunnel is parallel to the existing Nanning-Guangzhou high speed rail which is under construction.The distance from the edge of the track to the edge of the excavation is 20.5meters.It is concluded that impact of the cut-and-cover tunnel construction on the existing high speed rail should be evaluated.The safety evaluation criteria are established from the various design codes and existing construction practice.A typical section that represented the worst case scenario（distance between the excavation and the rail track,large excavation depth and unfavorable subsurface conditions）was selected for the finite element analysis.The influence of the active and inactive rail track on the cut-and-cover tunnel excavation were simulated.