复合地层条件下水下盾构隧道衬砌结构受力特征研究

针对工程中常用的无衬垫接头抗弯刚度非线性的特点，采用描述接头轴力、弯矩及转角关系的解析公式，提出盾构隧道衬砌结构受力计算的迭代计算方法。基于南京市纬三路过江通道的工程背景，分析了接头抗弯刚度的取值对盾构隧道衬砌结构受力及变形的影响，对工程中遇到的典型土岩复合地层中衬砌结构的受力进行了计算。计算表明，所提出的迭代计算方法简便易行，收敛较快，复合地层中衬砌结构的受力分布与均一地层中相差较大。复合地层的作用使得衬砌结构内力分布更不均匀，可能使得某一部分管片内力显著增大，设计时需要针对实际地层分布形式进行计算。

Mechanical Analysis of Segment Lining of Underwater Shield Tunnel in Composite Strata

An analytical solution on the relationship of axial force, moment and rotation of segment joints is employed in a proposed iterative algorithm for mechanical analysis of segment lining of shield tunnel, in which the nonlinear characteristic of bending stiffness of segment joints is fully considered. Under the background of Nanjing Weisanlu Yangtze River tunnel, the influence of bending stiffness of segment joints for the numerical solution of segment lining is analyzed. The mechanical behavior of segment ling in typical composite strata is also studied. Conclusions drawn are as follows: The proposed method is very convenient, the moment distribution of segment lining in composite strata is much different from that in the uniform strata. The composite strata increases the nonuniform distribution of moment in segment lining and may lead to remarkable increase of segment moment. Therefore the distribution of the actual strata should be considered in the design calculation. The proposed method and results of the analysis in this paper is valuable for the design of similar projects in practice.