既有盾构隧道抬升模型试验研究

Study on Model Test of Existing Shield Tunnel Uplift

隧道抬升纠偏是治理隧道沉降的有效办法,但抬升纠偏易导致收敛过大,引起隧道二次损伤。鉴于此,设计一种既有盾构隧道抬升模型试验系统,通过设置独立的纵向接头进行纵向结构模拟,以考虑隧道纵向接头对整体刚度的削减作用。综合考虑顶升量大小、抬升角度、截面刚度等影响因素,研究在抬升纠偏时隧道的竖向位移与截面变化规律。结果表明:低于45°的抬升角可避免隧道在抬升过程中产生过大变形;抬升位置靠近隧道纵向接头时,抬升主动环与相邻被动环的位移差将降低,隧道纵向位移曲线变缓;增设内部支撑可以促使隆起模式从断面变形过渡到整体隆起。

Tunnel uplift correction is an effective way of controlling tunnel settlement,but uplift correction is likely to cause overconvergence and thus secondary damage of the tunnel.In light of this,an existing shield tunnel uplift model test system is designed.Separate longitudinal joints are installed to conduct longitudinal structure simulation,in order to examine how the longitudinal joints in the tunnel will reduce the integral stiffness.With comprehensive consideration of the influencing factors including uplift magnitude,uplift angle and stiffness of section,the variation pattern of vertical displacement and cross-section of the tunnel during uplift correction is investigated.As the re⁃sults indicate:keeping an uplift angle less than 45°will prevent excessive deformation during tunnel uplift;when the uplift position is near the longitudinal joint of the tunnel,the displacement difference between the active uplift ring and the adjacent passive uplift ring will decrease,and the longitudinal displacement curve of the tunnel be⁃comes gentle;installation of internal support will cause the uplift model to change from section deformation to global uplift.