盾构隧道衬砌变形中接头转动影响分析

为研究盾构隧道衬砌收敛变形中纵缝接头的影响，引入接头转动引起的收敛变形占衬砌总收敛变形的比值作为纵缝接头对衬砌变形影响的评价指标。基于接头初始装配角以及接头间的几何递推关系，提出一种用于计算盾构隧道纵缝接头转动产生收敛变形量的简易算法。首先，通过与多尺度混合分析结果对比验证所提出简易算法的有效性。然后，应用该方法对足尺管片试验结果以及三维精细化数值模拟结果中通/错缝拼装、接头位置、衬砌纵向力大小、重复加卸荷等因素对纵缝接头在隧道收敛变形影响的变化规律开展研究。结果表明：通缝拼装下，接头转动引起的收敛变形在管片总变形中占主导地位，而错缝拼装可以显著降低纵缝接头在衬砌收敛变形中的影响；接头越靠近弯矩最大处，接头转动对整体收敛变形的影响越大；纵向力的增加提高了管片的整体性，故接头转动引起的收敛变形占比随着纵向力的增加而减小；加荷后卸荷，由于管片自身弹性变形可恢复而接头转动无法恢复，卸荷阶段纵缝接头的影响增大。上述研究结果可为实际工程中的管片结构设计及隧道健康状态评价提供参考依据。

Influence of longitudinal joint rotation on deformation of shield tunnel lining

In order to study the influence of longitudinal joints on the convergence deformation of shield tunnel lining, the ratio of the convergence deformation caused by longitudinal joint rotation to the overall convergence deformation was introduced as an index to quantify the impacts of longitudinal joints on convergence deformation. On the basis of the initial assembling angle of longitudinal joints and the geometric recurrence relationship between joints, a simple algorithm for calculating convergence deformation caused by longitudinal joints in shield tunnel lining was proposed. First, the effectiveness of the proposed simple algorithm was verified by comparing with the results of existing multi-scale hybrid analysis. Then, with the results of full-scale loading test and 3D numerical simulation, the simple algorithm was applied to analyze the changes in the influence of longitudinal joints considering factors such as persistent/staggered fabrication, joint position, lining longitudinal force, and alternating loading and unloading. Results show that for persistently fabricated lining, the convergence deformation caused by joint rotation played a dominant role in the overall deformation, while staggered fabrication significantly reduced the influence of longitudinal joint rotation on the convergence deformation. The closer the joint was located to the maximum bending moment area, the greater the influence of longitudinal joint on the convergence deformation was. The increase in the longitudinal force enhanced the integrity of the segment, so the joint rotation-induced convergence deformation decreased with increasing longitudinal force. During the unloading process after loading, the influence of the longitudinal joint increased as the elastic self-deformation of segments could be recovered but the joint rotation-induced deformation retained. The research findings can provide useful guidance on segment structure design and tunnel health status evaluation in practical engineering.