货运列车引起环境振动响应研究
Research on Dynamic Response of Environmental Vibration Induced by Freight Train

与传统客运列车相比，货运列车车型、编组、载重、运行车速的不同，其环境振动随机特性显著不同，且可能对沿线敏感目标造成更多振动影响。为对比分析客运列车、货运列车振源特性及其环境振动特性的差异，根据传递矩阵、傅里叶积分变换及坐标变换等方法，采用移动荷载状态激振，利用基于周期–无限结构理论建立的频域车轨动力耦合模型，计算得到4种不同车型(客运列车YZ₂₂、货运列车C_62A、C₇₀、C₈₀)作用下轨道扣件上的动荷载。建立轨道–路基–地层动力有限元分析模型，通过输入列车动荷载，在时域和频域下对比客运列车、货运列车通过时引起的地表振动响应特性。研究分析得到了不同列车作用下振动波在土层中的传播特点。研究表明，在相同运行速度条件下，由于列车的轴重、轴距、动力参数等的不同，轮轨动力相互作用引起的扣件上的动力荷载具有明显的差异，随着轴重的增加，振动低频成分增多，列车运行引起的环境振动水平也逐渐增加，轴重越大，振动波传播距离越远，振动衰减越慢。
Compared with traditional passenger trains, environmental vibration property induced by freight trains is significantly different due to vehicle types, vehicle marshalling, load capacity, and operating speed. Freight trains may cause more vibration effects on sensitive targets along railways. In order to compare the dynamic property of vibration source and environmental vibration, the coupled vehicle-rail model is established in the frequency domain based on periodic theory. According to the transfer matrix, Fourier integral transform, and coordinate transformation methods, the vehicle-rail model is excited by the moving load. Dynamic loads acting on the fasteners of 4 vehicle types (passenger train YZ₂₂, freight train C_62A, C₇₀, C₈₀) are obtained based on the vehicle-rail model. Based on the finite element model of track soil, the dynamic property of ground vibration induced by passenger trains and freight trains is analyzed in the time domain and frequency domain. Several conclusions are obtained as follows. Dynamic load acting on fasteners caused by wheel-rail interaction is significantly different due to the difference between axle load, axle distance, and dynamic parameters in different trains under the same operating vehicle. With the increase in axle load, low-frequency vibration and environmental vibration become larger. The greater the axle load, the further the vibration wave propagates and the slower the vibration damping.