基于牛顿运动学的盾构隧道管片上浮机理与控制

Mechanism and Control of Segment Floating of Shield Tunnel Based on Newtonian Kinematics

盾构隧道施工中,管片局部或整体上浮现象时有发生。为研究盾构隧道管片上浮机理,避免出现管片上浮、错台现象,在分析上浮位移特征的基础上,提出管片上浮运动模型,认为上浮过程主要分为2个阶段,第1阶段为匀加速上浮阶段,第2阶段为匀减速上浮阶段;对脱出盾尾后的隧道管片进行了详细的力学研究并提出相应的计算公式,考虑了上浮过程中浆液的动态上浮力、黏滞阻力、环间摩阻力以及螺栓剪力等,基于牛顿运动学推导出管片上浮量的理论解析解。结合北京地铁新机场线08标段盾构隧道工程,验证了上浮量理论解析解的准确性,通过分析影响管片上浮的主要因素,提出了相应的抗浮措施。

In the shield tunnel construction,the partial or overall floating of segments occurs frequently.In order to study the mechanism of segment floating in shield tunnels and avoid floating and stagger phenomenon of segments,a segment floating model is proposed based on the analysis of the characteristic of segment floating. It is considered that the segment floating process can be divided into two stages: the first stage is uniform acceleration and the second stage is uniform deceleration. Detailed mechanical research and corresponding calculation formulas are proposed for the tunnel segment after the shield tail.The dynamic buoyancy,viscous resistance,frictional resistance between rings and bolt shear force of the slurry in the process of floating are considered. The theoretical analytical solution of the segment buoyancy is derived based on Newton kinematics. Combined with the shield tunnel project of the 08 bid section of Beijing Metro New Airport Line,the accuracy of analytical solution of buoyancy theory is verified. By analyzing the main factors affecting the segment buoyancy,the corresponding anti-floating measures are put forward.