新建铁路隧道上跨既有隧道结构安全影响分析研究

ANALYSIS AND RESEARCH ON THE SAFETY IMPACT OF OVERCROSSING EXISTING TUNNEL STRUCTURES IN NEWLY BUILT RAILWAY TUNNELS

以既有屏峰山隧道与新建平公山隧道交叉区段的施工为例,采用数值模拟方法,分析了上跨施工对既有隧道变形和结构受力的影响。研究结果显示,新建隧道施工对既有隧道的位移、轨面沉降变形和钢轨高差影响较小,符合相关规范要求。同时,新建隧道的施工导致既有隧道二次衬砌轴力减小、结构弯矩增大,但其最小安全系数为5.81,高于规范要求的最低值3.6,不影响既有隧道的安全运营。该研究结果对于上跨既有线路施工具有重要指导意义。

Taking the construction of the cross section between the existing Pingfengshan tunnel and the new Pinggongshan tunnel as an object,the impact of the upper span construction on the deformation and structural force of the existing tunnel was analyzed by using numerical simulation method.The results show that the construction of the new tunnel has less impact on the displacement,deformation of track surface settlement and rail height difference of the existing tunnel,which is in line with the relevant specification requirements;at the same time,the construction of the new tunnel leads to a reduction in the axial force of the secondary lining of the existing tunnel and an increase in the structural bending moment,but the minimum safety coefficient of 5.81,which is higher than the minimum value of 3.6 required by the specification,and it does not affect the safety of the operation of the existing tunnel.The research results have important guiding significance for the construction of overpasses on existing lines.