Acoustic Environment Prediction And Impact On Human Annoyance Of Street Building

Urban environmental quality reflects the city's living level, but also it becomes an important symbol of the social development level. Healthy and comfortable urban environment includes natural environment (water, thermal, luminous, air and sound environment) and social environment (green, transportation, health, etc). And among them, sound environment is an important index for evaluating urban environmental quality. Meanwhile, the road traffic noise takes the largest proportion in all kinds of noise which influence urban environmental quality. In the paper, the impact of road traffic noise on the street buildings is studied from the aspects of noise prediction and annoyance, which provides the basis for the revision of noise standard and the noise control.The paper summarizes the research status of sound environment from all aspects, and introduces several kinds of evaluation index and standard of sound environment. Then, with Shayang road in Chongqing as research object, by means of field testing, the paper analyses the relationship between road traffic noise level and traffic flow, together with the change rule of noise along with horizontal and vertical direction of the building. Furthermore, the feasibility of simulation software is verified in the paper, through the noise prediction of street building by means of computer simulation. Finally, with the comprehensive consideration of the field testing result of road traffic noise and subject reaction of the residents to noise, the paper studies the impact of road traffic noise on the annoyance degree of residents. Then the conclusion is given as follows.①The traffic noise change curve of Shayang road in the daytime is close to a'V'style one. And the maximum value is 74.7dB, which appears during the time of 17:40 and 18:40, and the minimum value is 71.4dB, which appears during the time of 13:40 and 14:40. With the comparison between the measured value and the reference value which is defined as standard value of the region by both sides of urban main road in the quality criterion of noise environment, it shows that all of the measured value exceeds the standard value of 70dB, and the noise level in Shayang road is not satisfied with the standard. The paper also makes the conclusion that the variation tendency of traffic flow and traffic noise in the daytime is consistent. And the regression equation among medium-sized vehicle flow rate, motorcycle flow rate and road traffic noise level is established. ②The change rule of traffic noise level in the horizontal and vertical direction of building is gained. In the state of door-open, the indoor noise level is decreased by 5.3~13.7dB compared with outdoor. In the state of door-closed, the indoor noise level is decreased by 8.6~14.5dB. The variation tendency of noise level along the vertical direction is first-increase and after-decrease, while in the height of 10.5m, the maximum is reached by 65.1dB.③Based on the analysis between measured and simulated value, within the permitted average relative error, the feasibility of Cadna/A - noise simulation software is verified.④For the street building, the road traffic noise annoyance threshold of residents is 57.3dB, which is below the standard value 60dB of Class-2 region in the daytime defined in the quality criterion of noise environment. A positive correlation exists between the probability of annoyance and central sound pressure level, and the variation curve is Growth-curve..