隔舱式颗粒阻尼器在沉管隧道中的减震控制试验研究

Tests for compartmental particle damper's a seismic control in an immersed tunnel

基于修正的TLD设计理论,提出了一种适合沉管隧道使用的隔舱式颗粒阻尼器及其设计方法,并以某沉管隧道为原型,设计制作了1:60的缩尺模型,对设置颗粒阻尼器前后的模型隧道进行了振动台试验。研究结果表明:颗粒阻尼器对沉管隧道纵向的减震控制效果良好,能够有效地降低模型隧道接头轴力和相对位移等动力响应,颗粒堆积状态、较优附加质量比、激励频谱特性、激励强度是影响其减震效果的主要因素。颗粒阻尼器对沉管隧道的纵向基频有降低效果,而颗粒的附加质量比和堆积状态是调谐主体结构基频的关键因素。采用传递函数幅值可以表述模型隧道模态响应程度,提出了通过模型隧道的模态响应降低程度确定较优附加质量比的方法,并进而实现对主体结构低阶振型的有效控制。

Based on the modified design theory of TLD,a preliminary design method of compartmental particle damper for an immersed tunnel was presented. A 1 /60-scale model tunnel based on a certain immersed tunnel was designed. Shaking table tests of the immersed tunnel model with and without particle dampers were conducted. The results showed that the aseismic control of the particle damper in the longitudinal direction of the model has a better effect; the particle damper can effectively reduce the dynamic responses of the joint axial force and relative displacement of the tunnel model; the major factors influencing its damping effect are accumulation state of particles,better ratio of added mass,spectral characteristics of excitation and amplitude of excitation; the particle damper system can reduce the longitudinal fundamental frequency of the immersed tunnel,however,the ratio of added mass and accumulation state of particles are key factors to tune the fundamental frequency of the primary structure; the amplitude of the transfer function can be used to express the level of modal response of the tunnel model,therefore,the method to determine the better ratio of added mass is proposed with reducing the level of modal response of the tunnel model,and the effective control of lower order vibration modes of the primary structure is realized.