中文摘要：

为了弄清声屏障几何形状对高速铁路户外噪声的降噪机理和降噪效果,采用二维边界元法建立高架桥铁路声屏障噪声预测模型,分析不同几何形状结构参数对降噪性能的影响。分析中考虑列车运行速度、声源分布及频谱特性对插入损失的影响,根据车外声源识别结果建立符合我国高速铁路的声源模型;考虑车体-轨道-声屏障之间的多重反射,建立边界元计算模型;对顶部倾斜、T型、多重绕射边型、Y型、圆柱型等声屏障的结构参数的影响进行调查分析,分析中分别考虑插入损失、场点频谱及声场变化规律。研究结果表明,Y型声屏障降噪效果最好,平均插入损失提高3.4 dB（A）其次为圆柱型声屏障。

英文摘要：

The geometrical shapes of sound barriers have an effect on high-speed railway external noise. In order to make clear the noise reduction mechanism and effect of the sound barrier with different geometric head shape,the two-dimension（2D） boundary element method（BEM） is used to develop a noise prediction model for railway noise barrier. Using the model,the structure parameters of the different sound barriers are investigated and their noise reduction performance is analyzed. With taking into account the influence of train speed,sound sources distribution and their frequency characteristics on insertion loss（IL）,the sound source model of high-speed railway is developed according to the external noise source identification results. A BEM calculation model is developed on through sufficient considering the multiple reflections among train body,track and sound barrier. The noise reduction effects of sound barriers with sloping top,T-shaped top,multiple diffraction edges,Y-shaped top and cylinder-shaped top are surveyed. In the discussion,the changes of IL,frequency spectrum of field points and sound field are given. It＇s shown that the noise reduction effect of Y-shaped sound barrier is the best and the average IL is improved 3.4 d B（A）,secondly is the cylinder-shaped sound barrier.