盾构隧道衬砌整环力学机理模型

MODEL OF MECHANICAL BEHAVIOR WITH WHOLE SEGMENTAL LINING OF SHIELD TUNNEL

  • 摘要: 目前未见有普遍适用的理论公式来表征盾构隧道衬砌结构参数的内在联系。该文首先提出了用“代表性区段”体现整环结构弯曲刚度特征的思想,然后建立了通缝和错缝条件下管片环拼装力学机理模型,接着运用力学模型推导出弯曲刚度有效率和弯矩提高率等参数的取值公式和相互关系式,最后验证了公式的正确性。研究表明:力学模型能够推导出弯曲刚度有效率、管片体弯矩提高率、管片接头弯矩减少率、衬砌结构参数之间的关系公式;管片接头弯矩减小率未必等于管片体弯矩提高率,表明传统采用单一弯矩提高率值的做法不够科学;匀质圆环法还能给出环间接头径向最大剪力取值,并且其结果较为可靠;参数取值公式中有两个重要的中间参数,与环向相对刚度和径向相对刚度具有相似性,应予重视。参数取值理论公式的提出,对揭示盾构隧道整环拼装内在力学本质有着重要价值。

     

    Abstract: There is no universally applicable theory formula to characterize the inner contact of structural parameters of a shield lining structure at present. First, the “representative section” reflects bending stiffness of an entire ring lining structure was proposed, and an assembly mechanical model of a segmental ring with a sequence and staggered arrangement was built. Then the relation formulas for the effective ratio of bending rigidity and the transfer ratio of bending moment were derived by using the mechanical model. Finally, correctness of these formulas was verified. The study shows that the mechanical model can derive relation formulas for the effective ratio of bending rigidity, the bending moment transfer ratio of a segment body and a segment joint, and the parameters of a segment lining structure. The bending moment transfer ratio of a segment body may not equal the parameter of a segment joint, and this shows that the single value of a transfer ratio of bending moment is unscientific. A uniform rigidity ring model can also obtained the radial maximum shear parameter of a ring joint. We found that two intermediate parameters are very important, which similar to the circumferential and radial relative stiffness parameters of a lining structure. The parameter formulas proposed have an important value for the revealing inner mechanical nature of the entire ring lining structure of a shield tunnel.

     

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