Comparative analysis of environmental vibration characteristics in different regions of a metro depot

Abstract

The environmental vibration characteristics in different regions of a metro depot, such as the testing line area, the throat area and the repairing line were analyzed. The attenuation of the ground vibrations caused by three types of vibration sources were summarized, and the discrete characteristics of different sets of test data were compared by the statistical method. The environmental evaluation for each area in the metro depot was carried out. The results show that the main frequency of the ground vertical vibration in the testing line area is 60-80 Hz, that in the throat area is 50-60 Hz, and that in the repairing line area is 20-40 Hz. From the Z vibration level fitting curve for each working condition, it is found that the strength of the ballast foot vibration caused by train loads in the testing line area is the largest, followed by that in the throat area and that in the repairing line area is the lowest. In the throat area, compared to the track with concrete sleepers, the ground vibration of the track with polyurethane sleepers increases obviously and its attenuation rate is rather slower, consequently, the track structure and ballast bed should be optimized for vibration reduction. According to the criterion GB 10070-88, in the testing line area, the vibration level of the ground at a distance of within 5 m from the vibration source exceeds the limit; in the throat area, the vibration level of the ground at a distance of within 10 m from the vibration source exceeds the limit; in the repairing line area, the vibration level of the ground further than 2.5 m distant from the vibration source meets the limit requirement.