一种改进的盾构隧道双层衬砌计算模型及其工程应用

An improved model for shield tunnels with double-layer linings and its application in engineering

提出一种改进的盾构隧道双层衬砌计算模型,该模型可以反映接头抗弯刚度的非线性以及管片与二次衬砌接触面压剪弹簧失效机理。采用该模型对狮子洋隧道衬砌的力学行为进行了分析,结果表明:①管片结构最大正负弯矩随接头抗弯刚度增大而增大,而二次衬砌内力及管片结构最大轴力受接头抗弯刚度影响较小;②若不考虑管片与二次衬砌接触面的接触弹簧失效,将会使得计算结果量值偏大;③当盾构隧道所处岩层均匀时(t/D=0或1,t为结构范围内软弱层的厚度,D为隧道直径),全环各个位置处接头刚度值差别不大,当岩层不均匀时,接头抗弯刚度的取值差异分布显著;④径向弹簧、切向弹簧受力的最大值与平均值随着t/D的增加呈增大的趋势。

An improved model for shield tunnels with double-layer linings is proposed.It can reflect the nonlinear characteristic of bending stiffness of segment joints and the failure mechanism of compression and shear springs between segments and secondary linings.The internal force of linings of Shiziyang tunnel is analyzed using this model.The results show that:(1)The increment of bending stiffness of the segment joints can increase the values of the maximum positive and negative bending moments of the segments,while it has slight effect on the internal force of the secondary linings and the maximum axial force of the segments.(2)The internal force is larger than that in reality if the failure mechanism of springs between segments and secondary linings is not considered in the model.(3)The bending stiffness of joints varies slightly if the structure is situated in uniform strata(t/D=0 or 1,t is the distance from the tunnel top to the stratum interface,D is the diameter of tunnel),while its value varies sharply if the structure is situated in nonuniform strata.(4)The maximum and average forces of compression and shear springs will increase with the increment of t/D.