400 km·h^(-1)高铁桥上直立式声屏障脉动风压特性

Fluctuating Wind Pressure Characteristics of Vertical Sound Barrier on 400 km·h^(-1) High-Speed Railway Bridge

采用数值模拟法,建立400 km·h^(-1)列车通过高铁简支梁时作用于声屏障上的脉动风压模型,并通过某高铁桥上2.15 m高直立式声屏障脉动风压现场实测结果验证模型的正确性;基于建立的理论模型,研究声屏障内表面脉动风压分布规律,以及列车速度、列车中心到声屏障距离和声屏障高度等参数对脉动风压的影响规律。结果表明:高速列车行驶产生的脉动风压,头波正压峰值最大,在进行声屏障设计时应以头波正压峰值作为控制风压;沿声屏障自下而上,脉动风压峰值逐渐减小,在1.20 m以上高度衰减较快;脉动风压峰值与列车中心到声屏障距离的平方成反比,与列车速度的平方成正比;列车中心到声屏障距离由3.80 m增大至4.70 m,脉动风压峰值降幅可达28%;列车速度从350 km·h^(-1)提升至400 km·h^(-1)时,脉动风压峰值增幅最大可达30.5%;脉动风压随声屏障高度的增高而增大,但变化不明显。

The numerical simulation method was used to establish the fluctuating wind pressure model of 400 km·h-1 train acting on the sound barrier when passing through the simply supported beam for high-speed railway.The correctness of the model was verified by the field measurement results for the fluctuating wind pressure of the 2.15 m high vertical sound barrier on a high-speed railway bridge.Based on the established theoretical model,the distribution law of fluctuating wind pressure on the inner surface of sound barrier,the effects of train speed,distance from the train center to the sound barrier and the height of the sound barrier on the fluctuating wind pressure were studied.The results show that for the fluctuating wind pressure caused by high-speed train running,the peak value of head wave positive pressure is the largest,which should be used as the control wind pressure in the design of sound barrier.The peak value of fluctuating wind pressure decreases gradually along the sound barrier from bottom to top and the attenuation is faster at the height above 1.20 m.The peak value of fluctuating wind pressure is inversely proportional to the square of the distance from the train center to the sound barrier and proportional to the square of the train speed.When the distance from the train center to the sound barrier increases from 3.80 m to 4.70 m,the peak value of fluctuating wind pressure decreases by 28%.When the train speed increases from 350 km·h^(-1) to 400 km·h^(-1),the maximum increase in the peak value of fluctuating wind pressure can reach 30.5%.The fluctuating wind pressure increases with the increase of the sound barrier height,but the change is not obvious.