基于壳-弹簧模型的预制地下管廊横向抗震分析

Lateral seismic analysis of precast utility tunnels using the shell-spring model

利用ABAQUS有限元软件,采用壳单元模拟预制装配式地下管廊,非线性弹簧模拟管段承插口接头的力学行为,非线性地基弹簧模拟土-结构间相互作用,文中提出一种适用于预制管廊横向抗震分析的壳-弹簧计算模型。以天津市某拟建地下管廊为例,对4个计算工况进行了横向抗震分析。结果表明,壳-弹簧模型内力较梁-弹簧模型均有所增大,轴力、剪力、弯矩分别增大17.4%、22.7%和27.9%;考虑管段间钢绞线预应力时,内力在幅宽上有明显变化且在承插口接头处明显增高;引入管廊结构材料塑性后,管廊层间变形显著增大,且较之线弹性模型增大了68.7%。文中的壳-弹簧模型可反映预制综合管廊结构的弹塑性行为及接头钢绞线预应力影响,对预制综合管廊抗震设计有一定指导作用。

By using ABAQUS finite element software,the shell element is used to simulate the precast utility tunnel.The nonlinear spring is used to simulate the mechanical behavior of the bell and spigot joint,as well as the nonlinear soil spring is used to simulate the soil-structure interaction.A shell-spring model considering the influence of prestress of precast joint is proposed for lateral seismic analysis of precast utility tunnels.Taking a precast utility tunnel in Tianjin as an example,the lateral seismic analysis of four working cases is carried out in this paper.The results show that the internal force of the shell-spring model is larger than that of the beam-spring model.The axial force,shear force and bending moment increase by 17.4%,22.7%and 27.9%respectively.When considering the prestress of steel strand between tunnel segments,the internal force changes significantly within the segment and increases significantly at the precast bell and spigot joint.The deformation between top and bottom slab of the utility tunnel increases significantly after introducing material plasticity into the utility tunnel model.Meanwhile,the shell-spring model with structural plasticity increases by 68.7%compared with that of the linear model.The shell-spring model in this paper can reflect the elastic-plastic behavior of precast utility tunnel and the influence of the prestress of steel strand,which has a certain guidance in the seismic design of precast utility tunnel.