Study On The Simulation Of The Acoustic Environment Along The Rail Traffic Line

In recent years, with the development of our country's society economy and the increaseof the demand of people to travel comfortable, the rail traffic has become the maintransportion tool and developed fast. Meanwhile, the train speed has also been improvedconstantly. Subsequently, the pollution problem, of which the major problem is the rail trafficnoise, is seriously day after day, which has seriously affected people's work, study and dailylife.Since most rail transit lines near or through cities, while our urban population density islarger and the land area is less, if let the nearby residents away from the rail lines, then it willcertainly lead to large land waste and huge economic losses. So, in order to avoid the seriousaffect brought by the rail traffic noise to nearby residents and the economic losses for thenoise abatement, to simulate the acoustic environment along the line and to take effectivenoise reduction measures in the beginning of the rail line initial design are necessary. In thispaper, there is a study on the predition model of the acoustic environment along the rail traficline both domestic and international, with a view to simulate and predict the acousticenvironment rapidly and accurately.Firstly, it is from the basic theory of acoustics to study the noise source categories andthe acoustic wave propagation characteristics as well as the evaluation index and theevaluation standard of the acoustic environment along the rail trafic line both domestic andinternational, and to analyze and summarize the differences of the noise limits stated bydifferent national standards.Secondly, the advantages and disadvantages of the calculation principle in the rail trafficnoise prediction model for four country, including America noise prediction model, Germanyshal103 noise prediction model, Japan Hokuriku noise prediction models and the presentnoise prediction model of China, are analyzed and summarized in three aspects, the soundsource type, the sound source spatial location and the acoustic wave propagation attenuationcharacteristics.Thirdly, the noise prediction model of America, Germany, Japan and the presenttraditional noise of China are adopted respectively to predict, and compared with themeasured data got by the site investigation and the field monitoring to analyze the advantagesand disadvantages of each prediction model.Moreover, according to the advantages of the noise prediction model of America,Germany, Japan and the disadvantages of the noise prediction model in our country, therethe reference point noise radiation source intensity and the sound barrier equivalent frequency of the present noise prediction model of our country were modified. In order to verify therevision value of our prediction model is more approach the measured value, comparativeanalysis is carried out among the prediction datas of the modified prediction model and theprediction datas of the present prediction model in our country and the measured datas.As the prediction calculations cost of the traditional noise prediction model is too largeand the operation is complex as well as other disadvantages. This article adopts the visualbasic 6.0 programming language to program the noise prediction model of America, Germany,Japan and the present traditional noise of China. Meanwhile, it is comparative analyzed withthe manual calculation and the field monitoring data to verify the program's feasibility. It isexpected that the noise prediction will be programmed, visualization and simplified.