The Prediction Of Noise Reduction On Elevated Railway Sound Barrier

With rapid development of Chinese railway, railway noise has become an important factor restricting the development of railways and harming the health of human. In order to meet people’s railway acoustic environment quality requirements, in the construction of railway.we biuld railway bridge or viaduct and implement noise reduction measures on sensitive areas to go across residential areas and municipal roads. At the present, in China main noise reduction measure of railway bridges is sound barrier. It plays an important role in the railway bridge noise protection measures. However, sound barriers on different height of railway bridges have different reduction effect. In particular, there are many disputes about whether to set for a railway viaduct sound barrier,In this paper, we build railway bridge section of the sound barrier insertion loss prediction mode,l by analyzing the principle of sound barrier noise reduction and characteristics of railway noise, combining with the idea of Germany SchaI103 segment calculated, using Cadna/A noise prediction software. Prediction position is 30m away from the track centerline and 1.2m height above the ground. The Operating conditions:the speed is 220km/h, the number of running trains is 120 pairs/daytime and 0 pairs/night. Analyzing the correlation between the predicted and measured values of the field on sound barrier insertion loss of different heights railway, we can draw the applicability of Cadna/A software over railway bridge sound barrier insertion loss forecast. Further increasing the height of the bridge and using Cadna/A to predict the loss of railway viaduct sound barrier, we can analyze their applicability. We get the following conclusions:①By analyzing insertion loss between predicted and the measured values of sound barrier on different heights railway bridg, predicted values can Approximate the measured values with high accuracy. Which proofing that the desired objective is achieved. Therefore Cadna/A can be used in insertion loss values forecast in our coungtry.②Under the same working conditions, furtheiyr improving the height of the railway bridge, Cadna/A software can be used to predict the insertion loss values of viaduct sound barrier. According to the prediction results, when the altitude railway viaduct is increase gradually d. the sound barrier insertion loss values and the predicted point noise values and noise reduction of sound barrier are reduced gradually. Therefore, for a given height of the railway viaduct, the sound barrier can not be considered setting. In Class 4b acoustic environment functional areas, we can consider not to set the barriers. In Class 2 acoustic environment functional areas, we can set 1 meter height barriers to reduce the noise. When the height of noise barriers is more than 50-meter-high, we can consider not to set the barriers.