【作者】 高飞；

【导师】 夏禾； 郭薇薇；

【作者基本信息】 北京交通大学 ， 桥梁与隧道工程， 2011， 博士

【摘要】 随着城市规模的不断扩大,轨道交通成为市民出行重要的交通工具,由之引起的振动与噪声问题对人们的正常工作和生活带来了越来越严重的影响。高架结构是轨道交通系统重要的组成部分,其对周围环境的振动与噪声影响受到了广泛的关注。本文采用理论分析、数值计算和现场试验研究相结合的方法,系统地研究了高架轻轨列车引起的振动与噪声的发生机理、振动和噪声在高架桥梁、高架车站等不同高架结构中的分布规律和特点,噪声在车辆内部、车站结构内部和高架线路附近的空间分布和传播规律。主要工作和成果如下：1、使用有限元软件ANSYS建立了移动荷载作用下三跨连续梁的振动分析模型,以瞬态动力学方法计算了各跨跨中的位移和加速度的响应时程。通过试验证明,本模型的计算值与实测值十分接近。2、在ANSYS中建立了二维声场有限元模型,用流体单元(FLUID29)包围结构模拟空气场区域,使用无限吸收单元(FLUID129)建立空气区域的边界条件。以各跨跨中截面作为研究对象,计算了距离梁底面0.3m处的辐射声压变化时程、1/3倍频程及声场内声压的分布情况。又以A计权声压评价体系为基础,绘制了各跨辐射声场的等压线,研究分析了噪声的辐射衰减规律。3、采用有限元结合边界元方法推导了振动加速度与辐射声压之间的声传递向量。以该向量为联系纽带,建立了结构表面加速度和辐射声压之间的关系。这种方法可以直接通过结构表面振动加速度估算声场中任意点的声压,避免了有限元法计算量大,时间长的缺点,同时解决了边界元法求解中特征频率上非唯一性问题和奇异积分或超奇异积分问题。试验结果证明将声传递向量用于结构噪声的预测具有良好的精度。4、通过改变桥梁阻尼、刚度、质量、支座刚度、行车速度、车辆荷载、列车编组和单、双向行车等参数,分别计算了桥梁的振动响应及辐射声压级。计算结果说明对于轨道交通高架结构,采用合理的结构形式以及控制桥上车辆的行车状态可有效地降低结构的振动与噪声水平。5、对北京地铁五号线高架结构梯形轨枕试验段进行了现场试验,比较了梯形轨枕轨道相对于普通轨枕轨道减振降噪的效果。研究了高架结构周围的噪声衰减规律,在现场试验的基础上,建立了辐射噪声场预测模型。通过对首都机场快轨线高架桥梁段的现场试验,研究了在直线电机车辆运行的情况下,箱梁结构不同部位的振动响应与辐射噪声水平,对振动与噪声频谱进行了相干性研究。6、对北京市轨道交通车站站台及车厢内噪声进行了调查,分别比较了地下、地面和高架车站的噪声环境特点,测试分析了不同减振降噪措施的效果。对于北京南站候车区的噪声分布特点进行测试研究。通过对临近高架线路的某6层建筑物进行现场测试,比较了不同楼层受噪声影响的程度。更多还原

【Abstract】 With rapid development of city scale, the urban rail transit (URT) becomes an important public transport. However, the vibration and noise caused by URT have serious influence on people’s daily work and life. The elevated structure is an important component of this system, and its influence on the surrounding environment is concerned by more and more people.In this paper, study is made of the mechanism of structural vibration and noise caused by URT train, the distribution and characteristics of vibration and noise in different elevated structures, and the spatial distribution and propagation of noise inside vehicles, station halls and around elevated structure lines, by means of theoretical analysis, numerical calculation and filed experiment. The main research contents and results are as follows:1. A finite element model of three-span continuous beam with moving loads is established by ANSYS to calculate the displacement and acceleration responses of the bridge. The experiment results show that the calculated data is close to the measured data.2. A2-D finite element model of sound field is established by ANSYS. The fluid unit FLUID29is used to simulate the air field area around the structure, and the air-absorption fluid unit FLUID129to establish the boundary. The sound pressure change process at the bottom of beam, the1/3octave sound pressure and the sound pressure distribution of sound field of the middle cross-sections of each span are calculated. Based on the weighted sound pressure evaluation system, the contours of sound pressure are drawn and used in the analysis of noise radiation attenuation.3. To study the relationship of vibration and noise, an acoustic transfer vector is derived to contact the vibration acceleration with the acoustic radiation pressure by combining the finite element method with the boundary element method. By using the vector, the sound pressure can be directly estimated at any point in the sound field by structural surface vibration acceleration. The method may avoid the shortcomings of higher computational complexity and long time calculating in finite element analysis, and may solve the problem of non-uniqueness in characteristic frequency and singular integral or hypersingular integral in boundary element analysis. Finally, the experiment certificated that noise prediction with acoustic transfer vector has good accuracy. 4. By changing damping, stiffness, mass, support stiffness of the bridge, and vehicle speed, load, train formation and traffic in two directions, the dynamic responses of the bridge and the radiation pressure level are calculated. The results show that reasonable parameters adoption of bridge structure and control of vehicle state may effectively reduce structural vibration and noise levels.5. An in-site test was conducted on the elevated bridge test section of Beijing Metro Line5. The reduction effects of vibration and noise were measured and compared when trains ran on the ladder sleeper track and the common track. Based on the test data, the noise attenuation laws within a certain range of around the bridge, a prediction model for noise radiation is proposed. Another in-site test was conducted at a viaduct section of the Airport Express, by which the vibration and radiation noise levels in different parts of box girder structure were measured when a linear motor vehicle passed by. In addition, the coherence of vibration and noise spectra are studied.6. A survey of noise condition inside Beijing URT station halls was carried out, in which the noise characteristics in underground, ground and elevated stations were measured and compared, and the effects of different measures for reducing vibration and noise are analyzed. The noise was measured in the waiting area of Beijing South Railway Station. The noise levels were measured at different floors of a6-story building near a URT bridge.更多还原