考虑纵缝接头刚度折减的盾构管片性能研究

Study on the Performance of Shield Segment Considering the Reduction of Longitudinal Joint Stiffness

盾构隧道管片在纵缝接头处薄弱易损,研究其力学性能需考虑此部位的刚度折减。基于对原型管片、开槽管片在纵缝接头刚度上进行等效计算,构建一种可准确模拟纵缝接头刚度折减的双侧开槽盾构管片模型。同时,加入匀质圆环管片作为对照组,以覆土堆载模型试验为手段,研究接头刚度折减对管片受力变形的影响,以探明在考虑接头刚度折减条件下盾构隧道管片的力学性能,并结合数值模拟对模型试验可行性进行验证。结果表明:纵缝接头处刚性折减较大程度减小了管片横向刚度,从而加剧了管片收敛变形;纵缝接头刚度折减对管片轴力并无显著影响,但会导致弯矩包络线发生明显上移,使管片截面弯矩最大值增加近10%。

In the study of the mechanical properties of shield tunnel segments,it is necessary to consider the stiffness reduction of the segments at longitudinal joint because they are weak and vulnerable.Based on equivalent calculation of the longitudinal joint stiffness of the prototype segment and the slotted segment,a two-side slotted shield segment model which could accurately simulate the longitudinal joint stiffness reduction was obtained.At the same time,homogeneous ring segments were added as the control group,and the influence of joint stiffness reduction on the mechanical deformation of the segments was studied by means of the overburden model test,so as to explore the mechanical properties of shield tunnel segments under the consideration of joint stiffness reduction.The feasibility of the model test was verified by combining the numerical simulation results.The results show that:(1)the rigidity reduction at the longitudinal joint reduces the transverse stiffness of the segment to a large extent,thus aggravating the convergence deformation of the segment.(2)The stiffness reduction of longitudinal joint has no significant effect on the axial force of segment,but it will cause the bending moment envelope to shift up significantly,which increases the maximum bending moment of segment section by nearly 10%.