| Shield tunnel segment is the first layer of lining to support the stability of the tunnel, which is generally made of reinforced concrete material. With the development of computer technology in recent decades, the finite element method is widely applicated in engineering construction fields, which is also applied to the mechanical properties analysis and cross section design of shield tunnel segment.The analytic method and the finite element method are introduced and compared to calculate the internal force of shield tunnel segment. The influence of segment and ground parameters to segment is analysed using finite element method, especially the ground loss ratio. Research shows that the internal force value of segment will increase with the increasing of segment depth and diameter. The internal force of segment will decrease with the increasing of Poisson’s ratio. The internal force of segment will decrease with the increasing of ground loss ratio.The existing section checking theory is improved to analyzing the relationship of the limit bending moment and axial force of reinforced concrete segments and the real stress state of steel bars in compressive area. Research shows that reinforcement in compression zone does not reach the yield strength. Bending moment of the variation of the axial force in Wuhan subway and Shanghai subway shield tunnel segment is calculated. Research shows that bending moment will increase with the increasing of axial force. The most unfavorable load combination of the actual segment is the combination of maximum bending moment and minimum axial force.The section design of the Qiongzhou Strait Tunnel segment is analysed. The research shows that the reinforcement scheme of Qiongzhou Strait submarine tunnel should consider the combination of minimum axial force and maximum bending moment. The Qiongzhou Strait Tunnel Segment should use the segment with thickness of 700mm and width of 1000mm. The final match reinforcement scheme is given. |
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