考虑收敛变形的通缝拼装盾构隧道纵向等效抗弯刚度计算分析

为了研究运营地铁通缝拼装盾构隧道长期沉降过程中衬砌结构横向变形对其纵向变形和受力的影响,基于上海轨道交通8号线西藏北路站—中兴路站运营盾构隧道现场试验监测数据,对等效连续化模型进行修正,考虑隧道收敛变形对结构纵向变形的影响,并将该计算方法与现有计算方法进行对比分析。结果表明:1)弯曲状态下,环缝位置不考虑剪切作用时,随着隧道收敛变形的增加,拱底环缝张开量最大值、管片拉压应力和螺栓拉应力均略有减小。2)结构纵向变形曲率半径越小,隧道收敛变形对其影响越显著。3)在大曲率半径隧道结构纵向变形状态下,隧道收敛变形对结构纵向变形的影响可以忽略;不考虑轴向拉伸导致结构纵向变形条件下,结构弯曲导致的拱底环缝张开量较小。

Computational Analysis on Longitudinal Equivalent Stiffness of Shield Tunnel with Straight Joints Considering Convergence Deformation

The shield bored tunnel from North Tibet Road Station to Zhongxing Road Station on No. 8 Line of Shanghai Metro has straight segments joints. In the paper, the deformation of the lining structure of the shield bored tunnel is monitored, the equivalent continuous model is modified, the influence of the tunnel convergence deformation on the longitudinal deformation of the lining structure is considered, and comparison and contrast is made between the calculation method with consideration of the convergence deformation and the existing calculation methods, so as to study the influence of the transverse deformation of the lining structure on the longitudinal deformation and stress of the lining structure during the operation of the Metro system. The results show that: 1) Under bending conditions, the maximum opening of the ring joints at the invert, the tensile stress and compression stress of the segments and the tensile stress of the bolts decrease as the tunnel convergence deformation increases, without considering the shear at the ring joints. 2) The influence of the tunnel convergence deformation on the lining structure increases as the curve radius decreases. 3) Under the condition of the longitudinal deformation of the tunnel structure with large curvature radius, the influence of the tunnel convergence deformation on the longitudinal deformation of the lining structure can be ignored; Without considering the longitudinal deformation of the lining structure induced by axial tensioning, the opening of the ring joints at the invert caused by the structure curvature is small .