盾壳挤压上浮盾构隧道引起环缝凸榫损伤研究

Research on Damage of Ring-Joint Tenon of Uplift-Movement Shield Tunnel Caused by Extrusion of Shield Tail

盾构隧道施工过程中存在上浮问题,会出现盾构机尾部局部挤压管片的现象,引起环缝凸榫破损。受损环缝凸榫成为服役盾构隧道薄弱部位,增加环缝渗漏水等盾构隧道病害的发生概率。针对该问题,建立了11环盾构隧道三维有限元模型,分析了盾尾挤压位置和盾构隧道上浮程度对盾构隧道环缝凸榫的破坏作用。研究结果表明:(1)盾构隧道上浮越严重,受盾尾挤压作用引起的盾构隧道结构变形越大,环缝凸榫法向接触应力最大值呈增大趋势。(2)盾尾挤压位置越靠近环缝,盾构隧道相邻环变形差异越大,环缝凸榫法向接触应力增大速率越快。(3)盾构隧道上浮较小时,环缝凸榫不存在损伤。随着盾构隧道上浮增加,环缝凸榫受拉损伤因子增加。

During the construction process of shield tunnels,uplift-movement issues may occur,leading to partial squeezing of the segments at the tail of the shield machine and causing damage to the protruding tenons of the segment joints.The damaged protruding tenons become vulnerable areas in service for shield tunnels,increasing the likelihood of occurrence of tunnel defects such as leakage through segment joints.In this study,an 11-ring shield tunnel three-dimensional finite element model was established to analyze the destructive effects of the tail squeezing position and the degree of tunnel uplift-movement on the protruding tenons of the segment joints.The research findings are as follows:(1)the more severe the tunnel uplift-movement,the greater the deformation of the tunnel structure caused by the tail squeezing,and the maximum normal contact stress of the protruding tenons of the segment joints shows an increasing trend.(2)The closer the tail squeezing position is to the segment joints,the greater the deformation difference between adjacent rings of the tunnel,and the faster the increase rate of the normal contact stress of the protruding tenons of the segment joints.(3)When the tunnel uplift-movement is relatively small,there is no damage to the protruding tenons of the segment joints.However,as the tunnel uplift-movement increases,the tensile damage factor of the protruding tenons of the segment joints also increases.