高速铁路隧道出口微气压波噪声和缓解措施

High-Speed Railway Tunnel Micro-Pressure Wave Noise and Mitigation

摘要: 高速列车通过隧道过程中，压缩波传播到隧道出口向外辐射微气压波，可能产生音爆问题，对线路附近居民产生惊吓。随着列车不断提速，微气压波问题不可忽视。本文通过三维数值模拟方法，研究时速400公里隧道出口微气压波噪声和缓解措施。研究表明：出口无缓冲结构且地形为平地时，时速400公里隧道出口微气压波近似以球面波向外辐射，压力幅值随着距离增加近似成指数衰减。气流与隧道壁面相互作用，在隧道出口附近形成涡旋结构。压缩波经过短隧道无形变传播后直接在出口辐射的微气压波噪声声压级随着频率的增大逐渐衰减，低频成分噪声远场传播近似呈规则球形，随着频率的增加，声压级等值面变得杂乱，高频噪声远场传播特征呈现散射状。隧道出口微气压波噪声强度随着传播距离的增加逐渐衰减。隧道入口设置缓冲结构，不改变出口噪声空间传播特征，仅改变噪声强度，微气压波声压级在全频段均显著降低，声压级峰值减小22 dB，缓解率为16.3%。研究结果为评估和减缓高速铁路隧道微气压波问题提供理论依据。

Abstract: During the passage of a high-speed train through a tunnel, the compression wave propagates to the tunnel exit and radiates outward as micro-pressure waves, which may cause sonic boom issues, startling residents near the railway line. As train speeds continue to increase, the problem of micro-pressure waves cannot be ignored. This study employs a three-dimensional numerical simulation method to investigate the micro-pressure wave issue at the tunnel exit under 400 km/h conditions and explores mitigation measures. The research shows that for a tunnel without a buffer structure and with flat terrain at the exit, the micro-pressure waves at the tunnel exit under 400 km/h conditions radiate outward approximately as spherical waves, with the pressure amplitude decaying approximately exponentially with increasing distance. The interaction between the airflow and the tunnel wall forms vortex structures near the tunnel exit. The sound pressure level of the micro-pressure wave noise, radiated directly at the exit after the compression wave propagates through a short tunnel without significant deformation, gradually attenuates as the frequency increases. The far-field propagation of low-frequency noise components is approximately spherical and regular, but as the frequency increases, the sound pressure level contours become disordered, and the far-field propagation characteristics of high-frequency noise exhibit a scattered pattern. The intensity of the micro-pressure wave noise at the tunnel exit gradually attenuates with increasing propagation distance. Installing a hood at the tunnel entrance does not alter the spatial propagation characteristics of the exit noise but only reduces its intensity. The sound pressure level of the micro-pressure wave is significantly reduced across the entire frequency band, with a peak reduction of 22 dB, representing a mitigation rate of 16.3%. The research results provide a theoretical basis for evaluating and mitigating micro-pressure wave issues in high-speed railway tunnels.