地铁隧道穿越既有桥梁施工安全评估

Safety Assessment of Subway Tunnel Crossing Existing Bridge Structure

近年城市轨道交通基础设施大规模建设,使得地铁隧道近接既有桥梁结构施工项目数量与日俱增。新建地铁施工导致周边土体扰动可能会对既有桥梁运营带来安全隐患,因此,需对地铁穿越桥梁工程进行安全评估。本文以北京地铁19号线区间隧道穿越某立交南幅桥工程为依托,探讨新建地铁隧道穿越既有桥梁施工安全评估思路和方法,通过对桥梁数值模型基础采用施加强制位移的方式,计算确定桥梁允许变形值;基于岩土有限元分析软件对新建地铁下穿既有桥梁施工引起的附加变形进行分析,并对施工加固措施进行安全评价。

In recent years,with the large-scale construction of urban rail transit infrastructure,the projects of new subway tunnel closely passing through existing bridges are increasing day by day.The disturbance of the surrounding soil mass caused by the construction of the new subway may bring potential safety hazards to the operation of the existing bridge.Therefore,it is necessary to conduct safety assessment for the subway crossing bridge project.Based on the construction of the section tunnel of Beijing Subway Line 19 crossing the South Bridge of an overpass,this paper discusses the ideas and methods of the construction safety assessment of the new subway crossing the existing bridge,and calculate and determine the allowable deformation value of the bridge by applying the method of forced displacement to the bridge numerical model foundation;through the geotechnical finite element analysis software,the additional deformation caused by the construction of the new subway under the existing bridge is analyzed,and the safety of the construction reinforcement measures is evaluated.