Performance of Low-Height Railway Noise Barriers with Porous Materials

João Lázaro,Pedro Alves Costa,Luís Godinho,Matheus Pereira

doi:10.3390/app12062960

João Lázaro, Pedro Alves Costa + Show 2 more

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https://doi.org/10.3390/app12062960

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Journal: Applied sciences	Publication Date: Mar 14, 2022
Citations: 9	License type: CC BY 4.0

Affiliation: University of Porto, University of Coimbra

Abstract

Rail transport is the most sustainable transportation mode, with the lowest energy consumption and carbon footprint. However, the noise induced by railway traffic in urban regions is a significant drawback and several reports point out the risks and the amount of people suffering from direct exposure to railway noise. One of the most used mitigation measures for railway noise is the implementation of noise barriers. Although they offer a significant reduction in noise levels, their height makes people feel enclosed. Therefore, in the case of railway infrastructure, the solution to the problem may lie in the use of barriers with a lower height placed close to the railway track. As the noise-forming mechanisms are mainly located at the track level, placing the barrier in a position close to the track allows mitigating rail noise without causing the problems identified above for the population in the vicinity. The purpose of this paper is to illustrate the development of a barrier solution to be used in a railway context through numerical modelling with the Boundary Element Method (BEM). The solutions developed were placed close to the track and have a low height. The geometry was defined so as to direct the energy back to the track to take advantage of the acoustic properties of the ballast. The addition of a porous granular material on the inner face of the barrier allows the control of reflections between the vehicle body and the barrier, increasing its acoustic efficiency. Finally, considering the most efficient solution, the insertion loss in a network of receivers located 10 m away from the track is analysed in order to study the noise reduction levels in a place where human receivers are usually located.

Highlights

Railway transport is the most sustainable mode of transport, with the lowest energy consumption and carbon footprint compared to any other mode of transport.a report by the European Environment Agency (EEA) [1] from 2019 on this subject states that at the European level, rail noise is the second most dominant source, with an estimated 22 million people exposed to at least 55 dB during the day and night periods.On the same subject, with a different time horizon, the report by the EuropeanEnvironment Agency [2], whose aim is to project scenarios for the decade 2020 to 2030, states that the situation of the population’s exposure to environmental noise level in Europe will worsen in practically all areas responsible for current exposure levels
This document highlights the effects of noise and incorporates a number of indications for certain policies that must be implemented in order to ensure health and well-being for people living with the most diverse forms of environmental noise
It stresses that interventions to reduce noise levels and to comply with the limits indicated should focus on interventions at the track level, the improvement of rolling stock and the implementation of small noise barriers

Summary

Introduction

A report by the European Environment Agency (EEA) [1] from 2019 on this subject states that at the European level, rail noise is the second most dominant source, with an estimated 22 million people exposed to at least 55 dB during the day and night periods. Environment Agency [2], whose aim is to project scenarios for the decade 2020 to 2030, states that the situation of the population’s exposure to environmental noise level in Europe will worsen in practically all areas responsible for current exposure levels. This document highlights the effects of noise and incorporates a number of indications for certain policies that must be implemented in order to ensure health and well-being for people living with the most diverse forms of environmental noise. It stresses that interventions to reduce noise levels and to comply with the limits indicated should focus on interventions at the track level, the improvement of rolling stock and the implementation of small noise barriers

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