双层高架对轨道交通噪声空间分布的影响研究EI北大核心CSCD

运用振动功率流法计算轮轨粗糙度激励下的轨道和桥梁振动速度,采用二维声学模型计算单位荷载下轨道和桥梁结构的振动速度及辐射声压。联合前两步,根据振动功率等效原则预测钢轨和桥梁实际的辐射声压,某U梁现场实测轨道交通噪声验证了该方法的准确性。对比研究了合建高架和独立轨道交通的噪声分布特性,结果表明:(1)道路桥的屏障效应导致该桥面以上扇形区的噪声明显减小,到轨道中心线的水平距离越近,降噪值越大;(2)无声屏障时,道路桥面高度以下空间的噪声增大3~10 dB,到轨道中心线的水平距离越近,噪声增幅越大;(3)轨道交通桥上设置声屏障可进一步减小道路桥面以上的扇形区的噪声,同时增大其余区域的噪声。

Influence investigation of the rail-cum-road viaduct on noise spatial distribution from rail transit traffic

A power flow method is adopted to calculate the vibration velocity of track and bridge induced by wheel-rail combined roughness.A 2D acoustical model including track,bridge and sound field is used to obtain the mean square velocity and radiated sound pressure of the track and bridge produced by unit forces on the rail and bridge.According to the principle of vibration power equivalence,the actual sound pressure radiated from rail and bridge is determined by combining the two mentioned steps.The accuracy of the noise prediction method is validated by the measured results in field from a pure urban rail transit U-bridge.It is then used to compare the noise distribution characteristics from the pure rail transit bridge and double-deck viaduct composed of the upper urban road and the lower railway.The results show that:(1)the noise at the scalloped region above the upper bridge deck is obviously reduced by the upper road bridge,and the horizontal distance closer to the track centre,the greater the noise reduction;(2)the noise in the areas below the upper road bridge deck is increased by 3~10 dB without the noise barriers on the rail bridge,and the horizontal distance closer to the track centre,the greater the noise increment;(3)the noise barriers continue to reduce the noise in the scalloped region above the upper bridge deck and to increase the noise at the rest areas.These findings provide a beneficial reference to control the rail transit noise through the combination of noise barrier and the double-deck viaduct.