The noise measured at a point near a tunnel portal of Shinkansen includes the noise from the tunnel portal and the ordinary wayside running noise to make the noise level generally higher than that at ordinary points. To effectively reduce the noise level at such a point, therefore, it is necessary to know the contributions of both noise components. This paper describes a model to predict the noise from a tunnel portal which is used for road traffic noise and applies it to Shinkansen noise. It is confirmed that the model is valid in predicting Shinkansen noise, if some modifications are made. Furthermore, higher sound barriers near a tunnel portal and installing absorbing materials on tunnel walls are proposed as countermeasures and their effects are estimated on the basis of the prediction model.

Copyright (c) 2003 Railway Technical Research Institute