Investigation and assessment of environmental noise arising from railways: The case of Marmaray

Abstract

Today, the rapid population growth and the developing technology in the world lead to the depletion of resources and environmental pollution in global scale. Taking precautions becomes important in order to reduce the environmental pollution day by day. For this purpose, detailed studies are carried out on the prevention, reduction and disposal of major environmental pollutions such as soil, water, air and noise, which have become one of the most important problems in the world. The high population of the cities, the development of technology and transportation facilities have revealed the noise problem in city life. Noise is one of the main problems that reduce the life quality and affecting people's health negatively. For this reason, studies on noise around the world have been emphasized. Strategies for detecting the noise from any sources and taking precautions at the sources, transmission path and receiver are developed. In this context, noise measurements, noise calculations and the creation of noise models are among the studies that have come to the fore recently. Railway transportation has come to the fore in recent years as a highly sustainable transportation option with less energy consumption, less space needed for construction, less energy use during its operation and low amount of CO2 emitted into the atmosphere per capita. While the rail transportation in the city increases over time, the noise level caused by the railway also increases. Railroad noise is an intermittent noise, as it occurs during the passage of a train. The variation in this type of noise varies depending on the length, speed, weight of the train and the train transit time. In recent years, investment in railways has increased in Turkey rapidly, and rail system networks have been renewed. The increase in the need for and investment in railway transportation in Istanbul, the most populated city in Turkey, has led to the need to examine the noise originating from the railway in the region. Accordingly, the aim of this thesis is to examine and evaluate the environmental noise between Erenköy-Küçükyalı stations on the Gebze-Halkalı railway line. In this context, in the thesis study, first of all, sources of railway noise, factors affecting railway noise, measures taken to prevent railway noise were mentioned, and then previous studies on the subject were summarized. Then, in the thesis study, the legislation related to noise in Europe and Turkey is mentioned. In the Environmental Noise Evaluation and Management Regulation, the limit values for indoor noise in the buildings located in the train stations and the study area are presented, and within the framework of the Regulation on the Protection of Buildings Against Noise, the sensitivity levels in accordance with the use of the buildings are summarized with the table taken from the regulation. The reason of selection of this area between Erenköy-Küçükyalı stations is the close location of the residences which is accepted as the sensitive areas specified in the Regulation on the Protection of Buildings Against Noise (RPBAN) around the railway. Within the scope of the thesis studies, environmental noise calculations at the railway line had been made the usage of the Dutch International Calculation Method (Reken – Meervoorscrift Railverkeer slawaai 96) wherein data consisting of the rail type used at the Marmaray line. In the thesis study, noise measurements were made at the selected Erenköy-Küçükyalı stations on the Marmaray line. In the thesis, Soundplan 4.1 model was used to create noise maps and calculate noise at receiver points. This version of the Soundplan Modeling Program is suitable for use in small areas. In order to create the model of the region, the current maps obtained from the Istanbul Metropolitan Municipality were arranged and the height points were entered into the model and the topography of the region was processed into the model by creating a Digital Ground Model. Then, the buildings in the study area were entered into the model and the building heights were determined, and road information was assigned to the model in order to reflect the background noise found as a result of the measurements. The location of the noise barriers was determined in the field and entered into the model, the railway information was also processed into the model and the model results were obtained in the form of colored grid maps. In addition, by assigning receptor points around the stations, it has been determined whether the noise levels in the buildings are suitable according to the Environmental Noise Evaluation and Management Regulation or not. According to the noise measurement results made between Erenköy-Küçükyalı stations, when the adjustment factor used in the measurement results for the railway, which is foreseen in the ISO 1996-1 Standard, is taken as -6, the Leq calculated with long-time measurements is found as 59.2 dBA, while Leq of the background noise level is found as 65.7 dBA. In this case, it can be said that the dominant noise in the region originates from the highway in the background. Normally noise from railway and highway are very close to each other without adjustment factor; however, railway is accepted as less discomfort for people because it is intermittent noise. Lden value is calculated as 64.8 dBA with long-time measurements. According to the measurement, the Leq of train noise is calculated as 67.8 dBA and also Leq value calculated by the RMR-96 method gave the result of 67.8 dBA with -6 as adjustment factor. In railway line Lden interval is seen as 60-65 dBA at Erenköy region, 60-63 at Suadiye region, 63-66 dBA at Bostancı region, 63-66 dBA at Küçükyalı region in these grid maps. When the grid maps and Lden value calculated with long-time measurements are compared to each other, it can be said that this range is compatible the noise interval at grid noise maps. Accordingly, it has been determined that the noise levels at the stations are below the limit values in the Environmental Noise Evaluation and Management Regulation. For receiving points above the limit, noise barriers or velocity limits for trains can be applied.