异形盾构隧道衬砌结构计算模型和受力特征研究

首先通过原型整环管片力学试验研究了异形盾构管片环向接头转动刚度随隧道埋深增加的变化规律。基于试验成果建立了异形盾构管片壳-弹簧计算模型,并将原型试验结果与修正惯用法和壳-弹簧模型进行对比,给出了异形盾构管片内力分布模式,明确了修正惯用法作为异形盾构管片设计方法的可靠性,并将壳-弹簧模型推荐为能较为科学地反映异形盾构管片实际受力特征的计算模型。最后,基于壳-弹簧模型从经济和力学两个角度对异形盾构隧道与矩形和圆形隧道进行对比,证明了异形盾构应用于浅覆土地层的科学合理性。

Computational model and mechanical characteristics of linings of special-shaped shield tunnels

The change laws of rotational stiffness of ring joints with depth are analyzed based on the loading tests on three full-ring special-shaped shield linings. A computational model for shell-spring of special-shaped shield linings is established adopting the rotational stiffness of joints obtained from the prototype tests. The distribution mode of internal forces for special-shaped shield linings is determined. The test results obtained from the prototype tests are compared with those from the modified routine method and the shell-spring model. It is shown that the modified routine method as the common design method is effectively reliable, and the shell-spring model is recommended as the most effective computational model because the obtained mechanical characteristics of special-shaped shield linings are the closest to the reality. Finally, from the economical and mechanical perspectives, the application of special-shaped tunnels under shallow overburden condition is more scientific and reasonable in comparison to either the circular or the rectangular tunnels.