基于不同接头模拟方法的沉管隧道地震响应分析

Seismic Response Analysis of Immersed Tunnels Based on Different Joint Simulation Methods

沉管隧道是将沉管管节通过接头相连而成的纵向细长结构,接头的合理模拟至关重要。结合某沉管隧道工程提出两种接头模拟方法:沿截面均匀等效设置弹簧的方法和基于截面剪切键作用设置弹簧的方法。对于计算结果的对比分析表明:在纵向地震作用情况下由两种模拟方法得到的结果吻合较好,但在横向地震作用下沿截面均匀等效设置弹簧方法无法体现接头的抗剪特性。另外,横向地震作用时接头水平相对位移是纵向地震作用时的2~3倍,因此更应关注沉管隧道横向抗震性能。研究成果对沉管隧道合理简化模型的建立和应用有一定参考价值。

Immersed tunnel is a longitudinal slender structure constructed by connecting the immersed segments with joints.The joint is the key part and weak link of the tunnel under the earthquake impact.In this paper,two joint simulation methods were proposed based on the common connection methods of immersed tunnel engineering:the uniform equivalent spring setting method along the cross section and the spring setting method based on the shear key effect of the cross section.The calculation is carried out based on the two joint simulation methods.The comparative analysis of the calculation results of the two simulation methods shows that both of them are in good agreement under longitudinal ground motion excitation,they are quite different under transverse ground motion excitation because the method of setting uniform equivalent spring setting along the cross section cannot reflect the shear characteristics of the joint.Moreover,the horizontal relative displacement of joints under transverse seismic is 2-3 times of that under longitudinal seismic.Therefore,more attention should be paid to the lateral seismic performance for immersed tunnels.The research results have a certain reference value for the establishment and application of reasonable simplified analysis model of immersed tunnels.