【作者】 袁俊；

【导师】 吴敏哲；

【作者基本信息】 西安建筑科技大学 ， 结构工程， 2010， 博士

【摘要】 随着城市交通的不断发展,轨道交通引起的振动和噪声已成为不能忽视的环境公害,相应的减振降噪措施正成为研究的热点。本文首先对激励的产生机理和频谱特性进行了分析和归纳,用合成激励法模拟城市轨道交通的竖向激励,然后从浮置板轨道减振、屏障隔振、新型减振装置三个方面对城市轨道交通隔振减振机理及措施进行了深入分析,主要研究内容包括:(1)系统分析了振源激励的产生机理和频谱特性,总结了不同机理形成激励的解析模型,在时域和频域空间分别求解了轨道的响应。在此基础上,提出了合成激励法的思路,分析各种激励的频谱特征及对竖向振动的影响,对比轨道-隧道-土体中不同频率的振动响应,筛选出有重要影响的激励,通过对所选择的激励叠加,得出了在时域内城市轨道交通系统的振源竖向激励。(2)将浮置板轨道按施工方式和长度分为了连续现浇浮置板轨道和轨枕板式预制浮置板轨道,采用连续梁模型和离散梁模型分别模拟连续现浇浮置板和轨枕板式预制浮置板。基于Euler-Bernoulli梁和Timoshenko梁理论,给出了双层连续的Euler-Bernoulli梁和离散的Timoshenko梁模型,建立了双层离散Euler-Bernoulli梁和连续Timoshenko梁的解析模型。通过Fourier变换在波数-频率域内求解模型的频散曲线,分析了浮置板轨道结构的频散特性;再采用围道积分法进行Fourier逆变换求得结构系统在空间-时间域内的响应,比较了双层Euler-Bernoulli梁和Timoshenko梁理论的计算精度,评价了连续现浇浮置板轨道和轨枕板式预制浮置板轨道的结构特性和减振效果。(3)建立了三维浮置板轨道有限元模型,研究了尺寸参数和动力参数对浮置板动力特性的影响。对比了一维和二维浮置板轨道结构的频散变化,研究了钢轨、轨道、隧道的频散特性。(4)采用有限元法分析了隔振沟对地面轨道交通引起的低频振动的隔振效果,讨论了隔振沟深度、隔振沟距振源的距离、振源频率对振动隔离效率的影响。(5)提出了一种新型的减振措施―“振源传导桩”系统,将列车运行产生的振动通过轨道后完全传递至振源传导桩底部,使桩底成为新振源,让振动传至土层深部,减小地表振动,从而经济合理地实现减振。给出了“列车―轨道板―传导桩―土层”数值分析模型,建立了有限元模型进行参数分析,系统地评价了“振源传导桩”的减振性能。更多还原

【Abstract】 With the development of the urban rail transit, the vibration and sound caused by rail transit is becoming a serious environmental hazard that cannot be neglected, and the noise and vibration reducing measure becomes one of the hottest research topics. In this paper, the generation mechanism and spectrum characteristics of the excitation is analyzed and concluded. The vertical excitation of the urban rail transit is simulated based on compound excitation method, and mechanisms of vibration countermeasures are deeply analyzed, including floating slab track, wave barrier, and a new vibration damping system. The main content of this study is as follow:1. The generation mechanism and spectrum characteristics of the excitation are systematically analyzed. Resolution models of excitations generated by different mechanisms are summarized. The responses of the track are resolved in time domain and frequency domain respectively. On the basis of the above work, compound excitation method is proposed. Based on the analysis the effect of excitations on spectrum characteristics and vertical response and comparison the vibration responses of different frequency in track-tunnel-soil, the excitations that have obvious influence are filtrated. By superimposing the selected excitations, the compound excitation of the urban rail transit system under time domain is obtained.2. Floating slab track is cataloged as continuous cast-in-place floating slab track and discontinuous pre-cast floating slab track according to the construction method and length. These tow kinds of floating slab tracks are respectively simulated by continuous beam model and discrete beam model. Based on the theory of the Euler-Bernoulli beam and Timoshenko beam, the double continuous Euler-Bernoulli beam model and double discrete Timoshenko model are proposed, and the resolution model for double discrete Euler-Bernoulli beam and double continuous Timoshenko model are . The dispersion curve of the model is resolved in wavenumber-frequency domain by Fourier transformation, and the spectrum characteristic of the floating slab track structure is analyzed. The system response in space-time domain is obtained by contour integral and inverse Fourier transformation. The precise of the calculating is compared between double Euler-Bernoulli beam and Timoshenko beam, and the structure characteristic and damping effect of the continuous cast-in-place floating slab track and discontinuous pre-cast floating slab track are evaluated.3. The three-dimensional finite element model for floating slab track is established, and the effects of the dimensional parameters and dynamic parameters on dynamical characteristic of the floating slab are investigated. The dispersion characteristics of one-dimensional model and two- dimensional model of floating slab track are compared, and analysed the dispersion equations of rail-track-tunnel systematically.4. Based on the computing results of the finite element model, the vibration isolation effect on the low frequency vibration of the rail transit caused by trench is analyzed, and the effect of the depth of the trench, the distance between trench and vibration source, and frequency of vibration source on vibration isolation efficiency is discussed.5. A new vibration damping system -“Excitation Transmission Pile”system, can transfer the vibration induced by train to the bottom of the pile via track, and meanwhile, the bottom of the peg becomes the new vibration source, transferring the vibration to deep soil, reducing the ground vibration. The new vibration damping system can reduce vibration economically and reasonably. The numerical model of the“train-track slab-pile-soil layer”is established, and the vibration performance of the“Excitation Transmission Pile”system is systematically evaluated by parameter analysis.更多还原