一种新的盾构隧道双层衬砌解析分析方法

A new analytical solution for shield tunnel with double lining

基于欧拉曲梁理论,提出一种新的盾构隧道双层衬砌结构解析分析方法。该方法用考虑层间滑移的双层曲梁模型模拟双层衬砌结构,并引入接头弹簧考虑外层管片衬砌的接头效应,然后利用状态空间法求得任意地层荷载和接头分布形式下结构的内力和变形。通过与已有解析解和数值模型的结果对比,验证所提出方法的正确性。利用该方法探讨不同的接头分布形式对双层衬砌结构内力和变形的影响,并研究不同接头刚度条件下,双层衬砌变形和内力随层间剪切刚度的变化规律。分析结果表明:(1)增大层间剪切刚度可以增强双层衬砌结构的整体刚度,并引起轴力增大和弯矩减小;(2)接头弯曲刚度的变化对结构弯矩和变形的影响很大,而对轴向压力的影响较小;(3)当接头拉压刚度过小时,层间剪切刚度大的双层衬砌结构会呈现较大的内缩趋势而出现有别于"横鸭蛋"型的变形模式。该研究成果可以为盾构隧道双层衬砌结构的设计提供参考。

Based on the curved Euler beam theory,this paper presents an analytical solution for the double lining structure of shield tunnels.Partial-interaction composite curved beam theory is employed to simulate the double lining,and mechanical springs are used to reflect the radial joints effect.The solutions for the internal forces and deformations can be derived by the state space method for arbitrary loadings and variable joint distributions.The solutions revalidated by a comparison with the results of the existing analytical method and numerical model.Using the present solutions,the influence of different joint distributions on internal forces and deformations of the lining are discussed,and the variation trends of internal forces and deformations varying with interlayer shear stiffness between inner and outer linings are also examined under different joint stiffness conditions.The results show that:(1)Increasing the interlaminar shear stiffness can enhance the overall stiffness of the double lining,while the axial force increases,and the bending moment decreases.(2)The bending stiffness of the joint has a significant influence on the bending moment and deformation,but has less influence on the axial force;(3)When the tension and compression stiffness of the joint is too small,the double lining with larger interlayer shear stiffness will be more likely to exhibit a deformation mode different from the‘elliptical’mode because of the greater tendency of the inward contraction.The results obtained from this study may provide useful guidance for design of the double lining structure of shield tunnels.