Field test analysis of welding unevenness impact on subway track system vibration characteristics
In order to investigate the impact of welding unevenness on the vibration characteristics of subwaytrack structures, on-site dynamic and static tests are carried out under 3 conditions: 0.5 mm welding uneven-ness, 0.3 mm welding unevenness, and no welds. The time-domain, frequency-domain and vibration trans-fer characteristics of the vibration response for rail components under these conditions are compared. The re-search results indicate that the welding unevenness of the steel rail in the testing section exceeds the standard significantly, with a downward exceeding rate of over 50％. Furthermore, the varied shape of the steel rail welds leads to a substantial increase in subway vibration. The vibration response from the rail to the tunnel wall gradually decreases under the three conditions, indicating that the vibration mainly occurs between thewheel and the rail due to the interaction between them. The test section equipped with elastic long sleepers, experiences vibration response loss primarily between the sleepers and the track bed. This demonstrates good vibration reduction effects, with significant vibration response loss under uneven welding conditions. When welds are present on the steel rail, low-frequency vibration at each measuring point increases, and the fre-quency spectrum becomes richer, affecting passenger comfort. Compared with the condition without welds, the maximum increase in vibration values at each measuring point under the 0.3 mm welding unevenness con-dition and the 0.5 mm welding unevenness condition is 25％ and 650％, respectively. It is recommended to focus on the welding seam construction process and on-site acceptance process, strictly controlling the un-evenness of steel rail welding seams to not exceed the specified 0.3 mm limit in the standard.
万方数据
维普
