Research Article

Mechanical Behavior of the Special Segment Structure during Upward Shield Tunnel Construction

Table 1

Comparison of nine segment design methods.

NumberMethodsCircular jointsRadial jointsFeatures

1Uniform rigidity ring methodDo not considerDo not considerIt is widely used in Japan and is mostly used in sewer tunnels. Since the influence of the circular joints is not considered, it can be utilized to design segments with straight joints
2Improved uniform rigidity ring methodConsidered through reducing the lining stiffnessDo not considerThere may be problems in the calculation results of the axial force value calculated by this method in the range of 90∼180° with the vertical angle
3Average uniform rigidity ring methodConsidered through reducing the lining stiffnessConsidered through increasing or decreasing the bending momentIt can be used to design linings for small tunnels and relatively large tunnels. It can be utilized to design staggered segments
4Multihinge ring methodConsidered through a hingeConsidered through a hingeIt can be used to design linings in hard rock, and it can be utilized to design segments with straight joints
5Elastic hinge ring methodConsidered through a rotating springConsidered through a rotating springCompared with those of methods 1 and 3, the calculation results of method 5 are closer to the real value
6Beam-spring methodConsidered through a rotating springConsidered through a shear springIt can be used to design linings for large tunnels. It is suitable for large-scale tunnels
7Shell-spring methodConsidered through the discrete to joint units methodConsidered through the discrete to joint units methodIt considers the segment ring as a cylindrical shell. Theoretically, the internal force of the segment can be calculated more accurately, but it is difficult to determine the stiffness of the segment joint. If the unit is sufficiently small, it will lead to a sharp increase in the calculation amount
8Plate shell-joint element-foundation system methodConsidered through the block-to-block joint modelConsidered through the ring seam modelIt is a three-dimensional model, the segment ring is regarded as a flat shell, and the effect of the joint is considered by constructing the segment lining joint element model
9Flat shell-elastic hinge-foundation system methodConsidered through the elastic hinge modelConsidered through the elastic hinge modelIt is a three-dimensional model based on the Reissner–Mindlin plate element. The joint effects between each segment are considered through elastic hinge elements