类矩形盾构隧道T块相对拼装误差对立柱影响及其控制指标研究

Influence of Relative Erection Error of T Segments on Column and Its Control Indexes for a Quasi-Rectangular Shield Tunnel

相比圆形盾构隧道,类矩形盾构隧道在结构形式与拼装方式上有其特殊性。文章依托宁波轨交3号线类矩形盾构段工程,针对管片拼装过程中上下T块间存在的相对累积误差(六个方向自由度),建立了T块—立柱的三维有限元模型,分析了立柱在最不利荷载及姿态下的破坏机理,得出了立柱不会发生整体偏压破坏只会发生局部受压破坏的结论;并以混凝土主体(除边缘20mm外)不发生受压破坏及产生超过0.2mm的受拉裂缝作为标准,通过对单自由度及多自由度T块相对误差组合下的计算分析,提出了相应工况下的T块相对误差控制指标,可为施工控制提供依据。

In this paper,considering that quasi-rectangular shield tunnel has its own specificity on the structure and erection compared with the common circular shield tunnel and taking the quasi-rectangular shield tunnel section of Ningbo Metro line 3 as an example,a 3D finite element model of T segments and column was established aiming at the relative accumulated errors between the upper and the lower T segments during erection(six-direction DOF);the failure mechanism of column under the most unfavorable loading and attitude was analyzed,with the results showing that local compressive failure rather than overall non-symmetry compressive failure may occur on the column;a control indicator was proposed for the relative erection error of T segments based on a calculation analysis of relative error combinations of T segments under single DOF or multi-DOF,provided that compressive failure will not occur in concrete(except for 20 mm edge) and tensile cracks will be not more than 0.2 mm.