沉管隧道底板减重方案下结构受力分析

Structural Force Analysis Under the Weight Reduction Scheme of the Bottom Plate of Immersed Tunnel

为了减小沉管隧道管节重量,提高管节在浮运过程中的干舷高度,减少浮运航道疏浚量,提出将原底板的截面形式进行转换的管节减重方案。后使用有限元模拟软件对截面转换前后的隧道结构受力进行计算分析,研究截面转换对沉管隧道结构受力的影响。计算结果表明:底板截面形式转换后,顶板与侧墙处的结构内力大小几乎不受影响;底板跨中处由于结构自重减小,地基反力作用相对增强,导致底板跨中处弯矩相应增大;底板中墙端与侧墙端处由于底板跨中所分配荷载相对变大,所承担弯矩有一定程度上的减小。该计算结果为沉管隧道管节进一步优化设计提供了参考。

In order to reduce the weight of the pipe section of the immersed tube tunnel,increase the freeboard height of the pipe section during the floating process,and reduce the amount of dredging of the floating channel,a scheme for reducing the weight of the tube section by converting the section form of the original bottom plate is proposed.Then,the finite element simulation software was used to calculate and analyze the stress of the tunnel structure before and after the section conversion,and to study the influence of the section conversion on the stress of the immersed tunnel structure.The calculation results show that:after the section form of the bottom plate is converted,the internal force of the structure at the top plate and the side wall is almost unaffected;at the mid-span of the tunnel floor,due to the reduction of the self-weight of the structure,the reaction force of the foundation is relatively enhanced,resulting in a corresponding increase in the bending moment at the mid-span of the floor;due to the relatively large distributed load at the mid-span of the bottom plate at the end of the bottom wall and the end of the side wall,the bending moment assumed is reduced to a certain extent.The calculation results provide a reference for the further optimization design of the immersed tunnel tube.