In engineering practice, a large-diameter shield tunnel frequently extends through multi-layered strata. The behaviour of tunnels is more complex in multi-layered strata, but many designs are still constructed with the assumption that the soil is uniform. In this study, centrifuge tests and FEM analysis are conducted to investigate the mechanical behaviour of a large-diameter shield tunnel through multi-layered strata in terms of tunnel inner force and convergence. Two-layer strata and three-layer strata with different positions, inclinations, and thicknesses of the soft interlayer are considered, along with the relative stiffness of different layers. Both centrifuge tests and numerical simulation indicate that the relative stiffness of different layers and the position of the soft interlayer are the main factors affecting the behaviour of the tunnel in multi-layered strata. An increase in the relative stiffness leads to a significant reduction in the bending moment at the crown and springline. The maximum bending moment tends to appear in the soft layer. The distribution of inner force and convergence are asymmetrical owing to the inclination of the soil interface. Based on the results, some design suggestions are presented for large-diameter shield tunnels in multi-layered strata. Segment joints are discouraged near the soil interface and the ground around the tunnel can be considered to be soft soil when the interface is below the springline. In addition, the bending moment should be concerned carefully when the tunnel extends through the soft interlayer.

在工程实践中，大口径盾构隧道经常贯穿多层地层。隧道在多层地层中的行为更为复杂，但许多设计仍然假设土壤是均匀的。在这项研究中，离心机试验和有限元分析用于研究大直径盾构隧道穿过多层地层的隧道内力和收敛性的力学行为。考虑了软夹层位置、倾角、厚度不同的两层和三层地层，以及不同层的相对刚度。离心试验和数值模拟均表明，不同层间的相对刚度和软夹层的位置是影响多层地层隧道行为的主要因素。相对刚度的增加导致冠部和弹性线处的弯矩显着降低。最大弯矩往往出现在软层。由于土壤界面的倾斜，内力和收敛的分布是不对称的。在此基础上，提出了多层地层大直径盾构隧道的设计建议。在土壤界面附近不鼓励分段接头，当界面低于弹力线时，隧道周围的地面可以被认为是软土。此外，