中文摘要：

根据我国新建高速客运专线和200km·h^-1既有线提速改造的实际情况，以有砟轨道结构为研究对象，进行轨道结构动态响应有限元建模与轨道不平顺影响的动力分析、落轴冲击数值计算和不同垫层隔振性能分析、无缝线路钢轨振动特性谐波响应分析及室内实尺模型试验，研究轨道结构动态特性。

英文摘要：

According to the practical situations of the newly-built high-speed dedicated passenger lines and the existing 200 km · h^-1 speed-increase railway lines in China, the structure of ballast track is studied in terms of track dynamic response analysis, establishing the railway track FEM model, the influence of track irregularity, the numerical computation of wheel load drop, the performance analysis of various isolation pads, the investigation on CWR vibration Characteristic through the harmonic response way and the indoor full-scale model experiment. With the regularity of railway track along its longitude, a spatial FEM model is established on the numerical computation method of track element which is 0.6 m long as equal as one sleeper spacing and includes the dynamic characteristics of one sleeper as well as corresponding rail mass, fastening, pad, ballast and subgrade. In addition, through ＂cutting and merging＂ timely one or more track elements in the front and rear end of the vehicle, the dynamic response of a boundless track can be investigated. The comparison between the theoretical calculation and the test results shows that the FEM model can be used to reflect the vibration characteristics of track structure. Depending on the theory of vehicle-track coupling dynamics and the numerical comPutation method of track element, the influence on dynamic response of the wheel-rail system excited by rail surface vertical short-wavelength roughness in CWR weld joint with height difference is systematically discussed under different running velocity as well as track irregularity amplitude, and, the variation of dynamic behavior is described. The various short-term wavelength track irregularities such as ragged weld joint, gage line shelly cracks and rail surface scratching which should be cancelled promptly would intensify the wheel-rail＇s interaction obviously and accelerate the ballast crushing which lead to the ballast as well as the subgrade differential settlement and the track deterioration. Moreover