封顶块位置对地铁隧道管环力学性能影响研究

在盾构隧道施工和运营期,封顶块位置对盾构隧道的整体结构受力及变形有显著影响,因此对其位置的合理选择进行研究非常必要。采用ABAQUS有限元软件建立壳—弹簧模型,对封顶块不同软土不同埋深及在不同位置下盾构隧道通用管片结构力学行为进行研究分析。结果显示:同种软土中,通用管片整体结构弯矩随着埋深增加,弯矩增大;同种埋深下,随着软土由坚硬到软弱,弯矩逐渐增大。通用环封顶块在拱顶和拱底时,结构弯矩最大,对结构安全最不利;其次为两侧拱肩位置;封顶块在两侧拱腰以上,拱肩以下时结构弯矩值最小,对结构安全最有利,其次为两侧拱腰偏下位置。研究结果可以对施工阶段封顶块点位选择提供指导,同时还能为设计阶段的管片优化设计提供理论参考。

Study on Influence of Position of Capping Block on Mechanical Performance of Metro Tunnel Pipe Ring

During the construction and operation of the shield tunnel, the position of the capping block has a significant impact on the overall structural stress and deformation of the shield tunnel. Therefore, it is necessary to study the reasonable selection of its position. The shell-spring model was established by ABAQUS finite element software. The mechanical behaviors of different sections of different soft soils of the capping block and the general segment of the shield tunnel were studied and analyzed. The results show that in the same kind of soft soil, the bending moment of the overall structure of the common segment increases with the depth, and the bending moment increases. Under the same burial depth, the bending moment increases with the soft soil from hard to weak. When the universal ring capping block is in the vault and the bottom of the arch, the structural bending moment is the largest, which is the most unfavorable for the structural safety; the second is the position of the arched shoulders on both sides; the capping block is above the arched waist on both sides, and the structural bending moment value is the smallest when the arched shoulder is below. It is most beneficial to structural safety, followed by the lower side of the arch waist. The research results can provide guidance for the selection of the top block in the construction stage, and provide a theoretical reference for the design optimization of the segment at the design stage.