不同地层下大直径盾构隧道列车振动响应研究

Study on Train Vibration Response of Large Diameter Shield Tunnel under Different Ground Conditions

为了探究带中隔墙的管片结构在不同地层下列车动力响应的差异,结合上海机场联络线工程中隔墙顶部“韧性节点”设计方案,建立考虑不同地层情况的道床-衬砌-土体三维有限元模型,采用动力时程的分析方法,研究了盾构隧道在不同地层时所受列车荷载的动力响应规律。结果表明:“韧性节点”的设计有利于优化隧道中隔墙的受力;列车荷载通过隧道结构时,衬砌底部的动力响应最大,腰部次之,衬砌顶部最小,衬砌顶部动力响应较底部减小了12.3%;隧道周围土体刚度越大,其加速度响应越小,衬砌变形越小;在振动响应传递的过程中,黏土地层的耗散最小,砂土地层的耗散最大,相差38%。综合分析来看当隧道位于黏土地层中时,需要加强衬砌结构的减振措施。

In order to explore the difference in the dynamic response of the segment structure with the partition wall in different strata,the article combines the Shanghai airport contact line project with a design of"ductile joint"in the top of middle partition wall to establish a three-dimensional finite element model of the track bed-lining-soil which considers the different strata conditions.The analysis method of dynamic time history studies the dynamic response law of the train load when the shield tunnel passes through different layers.The results show that:The design of"ductile joint"is beneficial to optimize the stress of tunnel middle partition wall.When the train load passes through the tunnel structure,the dynamic response of the bottom of the lining is the largest,followed by the waist,and the top of the lining is the smallest.The dynamic response of the top of the lining is reduced by 12.3%compared with the bottom.The greater the stiffness of the soil around the tunnel,the smaller the acceleration response and the smaller the deformation of the lining.During the transmission of vibration response,the dissipation of the clay layer is the smallest,and the dissipation of the sand layer is the largest,with a difference of 38%.From a comprehensive analysis point of view,when the tunnel is located in the clay layer,it is necessary to strengthen the damping measures of the lining structure.