中低速磁浮快线车-轨耦合振动源强特性试验

Vibration Source Intensity Characteristic Experiment of Low-medium Speed Maglev Vehicle-Rail Coupling

中低速磁浮快线作为一种新兴的城市轨道交通型式,其车-轨耦合作用实测资料很少。通过对长沙中低速磁浮快线提速试验中的轨道-桥梁系统车致振动实测数据进行分析,结果表明:轨道-桥梁系统的振动随传播距离增加而逐渐衰减,以从钢枕端部到承轨台的衰减最为显著;轨排接头对振动从钢枕到承轨台的传播具有“路径阻断”效应,主要出现在20 Hz以下的频率范围;钢枕测点2~200 Hz的振动分量Ⅲ型接头断面较轨排中部断面大,承轨台测点振动的优势频段为63~125 Hz;在以设计速度100 km/h运行工况下Ⅲ型接头断面、轨排中部断面的环境振动源强L_(vl,z,max)分别为81.4 dB和81.1 dB,提速至150 km/h时均为84.2 dB;两个断面的环境振动源强均与行车速度表现出比较显著的线性关系,可按本研究给出的L_(vl,z,max)-v表达式进行源强计算。

As a new type of urban rail transit,the low-medium speed maglev has little documentation on field measured results of vehicle-rail coupling interaction.By analyzing the field measured vibration data of track-bridge system of Changsha Maglev Express in speed-raising test,the results show that the vibration of track-bridge system gradually attenuates with the increase of propagation distance,and the attenuation from sleeper end to rail support is the most significant.There is a′path blocking′effect of rail row joint on the vibration propagation from sleeper to rail support,which is mainly reflected in the frequency range below 20 Hz.TypeⅢjoint section with sleeper measuring point of 2~200 Hz vibration component is larger than rail row middle section.The dominant frequency band of measuring point vibration at rail support is 63~125 Hz.Under the operating condition of design speed of 100 km/h,the environmental vibration source intensity L_(vl,z,max) of typeⅢjoint section and rail row middle section become 81.4 dB and 81.1 dB respectively,and both are 84.2 dB when the speed is raised to 150 km/h.The environmental vibration source intensity shows a significant linear relationship with the running speed,and the source intensity can be calculated according to the L_(vl,z,max)-v expression given in this study.