地铁车站隧道群近接既有桥梁结构施工的安全影响分析

Study on the Influence of the Construction of Metro Station Tunnel Group on the Adjacent Existing Bridge Structure

随着城市轨道交通建设的发展,地铁隧道近接既有桥梁结构施工越来越多。北京地铁19号线以及12号线换乘车站北太平庄站,在北太平桥处南侧与北太平桥长距离并行施工,且北京地铁19号线区间隧道为小净距隧道,南北向垂直横穿北太平桥。地铁车站隧道群的施工不可避免地对北太平桥产生扰动,从而引起桥梁上部结构的附加沉降,影响通车运营。文章以车站隧道群近接既有桥梁结构施工为例,以桥梁现有结构状态为基础,研究了桥梁极限位移变形,提出了桥梁的附加变形标准,基于FLAC^(3D)建立三维数值模型,对地铁车站隧道群近接桥梁结构施工引起的附加变形及受力进行了全过程的分析和计算,对桥梁加固措施的安全性进行了评价。结果表明,桥梁结构的附加变形能够满足要求,现场监测数据也证明了其安全性。

With the development and construction of urban rail transit,more and more tunnels are constructed near the existing bridge structure.Beitaipingzhuang interchange station of Beijing metro line 19 and 12 is located at the south of Beitaiping bridge and parallel to Beitaiping bridge in long distances.The running tunnel of metro line 19 crosses the Beitaiping bridge with small spacings from north to south.The construction of tunnel group will inevitably disturb the Beitaiping bridge,which causes the additional deformation of the bridge.Based on the structural state of the Beitaiping bridge,the max additional deformation was studied and the additional deformation standard of the bridge was proposed.A three-dimensional numerical model was established based on FLAC3 D,to analyze the additional deformation and stress caused by tunnel group construction adjacent to bridge structure and evaluate the safety of the bridge reinforcement measures.The results show that the additional deformation of bridge structure can meet the requirements,and the field monitoring data also proves its safety.