盾构隧道纵向等效弯曲刚度的简化计算模型及影响因素分析

Simplified calculation model for longitudinal equivalent bending stiffness of shield tunnel and its influence factors' analysis

盾构法隧道在国内的应用越来越广泛,早期建造的盾构隧道在工后沉降较大时出现较大的纵向变形问题,考虑隧道结构特征的设计模型及其刚度计算逐渐得到重视。在考虑管片螺栓等结构特征基础上,建立可考虑环缝张开的三维纵向结构计算模型。研究结果表明,与管片环接缝相关的影响因素,如螺栓的数量、螺栓的预紧力以及管片环宽度对纵向弯曲刚度有效率影响较大,随着纵向螺栓数量和管片环宽度的增加而线性增加,随着螺栓预紧力的增加而非线性快速增加,而管片环的横向弯曲刚度有效率影响较小。研究成果为盾构隧道纵向设计提供了关键参数。

As shield tunnelling method is applied widely, the longitudinal uneven settlement of shield tunnel has emerged because of the comparatively large settlement after construction, and the designing method has been emphasized gradually, which can consider the longitudinal structure characteristics of shield tunnel. For the purpose of determining the longitudinal equivalent bending stiffness, a 3D calculation model has been established, considering the longitudinal bolts＇ characteristics and the ring seams＇ true splaying states. The results show that some factors related to the ring seam, for example the amount of longitudinal bolts, the assembly pretightening force and segment ring width, influence the longitudinal bending stiffness largely, which increases linearly with the amount of longitudinal bolts and the segment ring width, and which nonlinearly increases with the assembly pretightening force. Other factors related to the longitudinal seam, for example the transverse effective rigidity ratio, influence it less. The results provide key parameters for the longitudinal design method of shield tunnel.