浅埋超大直径盾构隧道千斤顶推力对衬砌管片受力变形的影响研究

为研究浅埋超大直径盾构隧道在不同千斤顶推力及偏移作用下的衬砌结构受力及变形规律，运用有限元软件ABAQUS建立考虑水土压力、盾尾刷反力、千斤顶推力的盾构隧道衬砌管片三维模型，并分析衬砌管片在盾构直行、上行、下行以及左行条件下发生偏角时的衬砌内力及变形情况。结果表明： 1）千斤顶推力对衬砌管片的影响范围主要为前8环，明显反应在前3环，且环内最大错台位置主要集中在封顶块位置附近； 2）盾构掘进方向主要影响该方向的管环位移，对垂直方向的管环位移基本无影响； 3）拱顶/拱底主要受俯仰偏角影响，不受横摆偏角作用，拱腰则对横摆偏角更为敏感，受俯仰偏角影响较小； 4）当千斤顶发生俯仰偏角时，向下偏角极易引起前几环管片的应力激增； 5）当千斤顶发生横摆偏角时，同侧偏角更易引起该侧管片的位移及应力激增。

Impact of Jack Thrust on Force and Deformation of Segment Linings for Shallow Buried Shield Tunnel with Super Large Diameter

In order to study the structural force and deformation laws of shallow buried shield tunnel with super large diameter under different jack thrusts and deflections, a three dimensional model of shield tunnel lining segments considering water and soil pressure, shield tail brush reaction force, and jack thrust is established with finite element software ABAQUS. The internal force and deformation of lining segment are analyzed when the lining segment is deflected under the conditions of straight, upward, downward, and leftward movement of the shield. The results show that: (1) Jack thrusts mainly influence the first 8 rings of lining segment, in which the first 3 rings is more obvious, and the largest dislocation position in the ring is mainly concentrated near the capping; (2) The tunneling direction of shield mainly affects the displacement of the rings in this direction, instead of that in vertical direction; (3) The vault/bottom is mainly affected by vertical deflection angle and not affected by the lateral deflection angle, and the waist is more sensitive to lateral deflection angle and is less affected by vertical deflection angle; (4) When the vertical deflection angle occurs, the downward deflection angle is very easy to cause stress surge in the first few ring segments; (5) When the lateral deflection angle occurs, the ipsilateral deflection angle is more likely to cause displacement and stress surge in side segments.