移动荷载作用下悬浮隧道管体TMD减振分析及优化布置

TMD Vibration reduction analysis and optimal layout for submerged floating tunnel tube under moving load

为减小悬浮隧道管体在移动荷载作用下的动力响应,采用TMD作为振动控制措施并对减振效果进行了分析。将悬浮隧道管体简化为弹性地基梁,采用移动简谐力模拟汽车荷载,通过Morison方程计算管体振动过程中的流体附加惯性效应和阻尼效应,推导建立了移动荷载作用下管体-TMD系统振动控制方程组。采用Newmark-β法进行数值求解,分析了TMD对悬浮隧道管体的减振效果。针对悬浮隧道管体振动特征,提出采用分布式TMD的布置形式,并对移动速度、TMD阻尼比的影响进行了讨论。结论表明:TMD对移动简谐荷载作用下的悬浮隧道管体具有显著减振效果,最大位移减振率在50%以上。由于多阶模态参与振动,单一TMD的有效减振范围有限。在保持总质量不变的情况下,采用分布式TMD可以获得较好的整体减振效果。提高TMD质量比和降低移动荷载速度有助于提高TMD的减振效果。增大阻尼比会减弱TMD的效果,应综合考虑减振效果和工作空间的要求确定。

Here,to reduce dynamic response of submerged floating tunnel(SFT)under moving load,TMD was taken as a vibration control measure and its vibration reduction effect was analyzed.A SFT tube was simplified as an elastic foundation beam,and a moving harmonic force was used to simulate vehicle load.Fluid additional inertia effect and damping effect in pipe vibration process were calculated using Morison equation.Vibration control equations of pipe-TMD system under moving load were derived and established.Newmark-β method was adopted to numerically solve the equations.The vibration reduction effect of TMD on SFT was analyzed based on the calculation results.Aiming at vibration characteristics of SFT,a distributed TMD layout was proposed and effects of moving load speed and TMD damping ratio were discussed.The results showed that TMD has a significant vibration reduction effect on SFT under moving harmonic load,the maximum displacement vibration reduction rate is over 50%;due to tunnel pipe vibration contains multiple modes,the effective vibration reduction range of a single TMD is limited,using distributed TMD can obtain better overall vibration reduction effect under the condition of the total mass keeping unchanged;improving mass ratio of TMD and reducing moving load speed can be helpful to improve the vibration reduction effect of TMD;increasing TMD damping ratio can weaken the vibration reduction effect of TMD,and it should be determined by comprehensively considering vibration reduction effect and requirements of working space.