关键词: 盾构隧道, 盾构切桩, 管片作用力, 控制措施

Abstract: To obtain the vertical load and vertical bearing capacity of the residual pile after removing the bridge pile foundation by shield cutting, the structural safety of bridge and shield tunnel after the pile cutting is evaluated, and the calculation and analysis on the force of residual pile on segment is conducted. First, the influence factors of residual pile on segment force after pile cutting by shield, including pile length reduction, construction disturbance and vertical stiffness change of bridge pile, are analyzed. Then, on the basis of influence factors mentioned above, the calculation formula for residual pile bearing capacity and vertical load is established, and is applied to project practice. The results show that the bearing capacity of the residual pile in this project cannot meet the vertical load requirement, which leads to grounting reinforcement of the foundation around the residual pile. The calculation results of foundation after grouting reinforcement show that the bearing capacity of the residual pile can meet the vertical load requirement, which ensures the safety of the segment and the upper bridge structure. Finally, according to the theoretical and practical analysis, the construction control measures to reduce the force of the residual pile on shield tunnel segment are proposed, including reducing the construction disturbance, improving the lateral friction of the pile and strengthening the rebars and bolts of segment.

Key words:  shield tunnel; pile cutting, pile foundation force on segment, control measures