【摘要】 研究目的：随着高速铁路的迅猛发展，为满足线路平顺性和跨越复杂地形的需求，大跨度桥梁被广泛应用在铁路上。由于无砟轨道与大跨度桥梁刚度相差较大，目前已出现轨道结构适应性不良、几何形位较差等问题，因此确保列车在大跨度桥上无砟轨道安全运行成为当前重要的议题。本文以实际工程为研究背景，以设计速度160 km/h、主跨688 m大跨度斜拉桥上无砟轨道为研究对象，从频域、时频域等维度出发，多维多角度探究轨道几何形位的平顺性。研究结论：（1）频域分析发现各工况的不平顺能量主要集中于长波频段（200 m以上），列车在跨中对轨道高低平顺性影响最大；（2）时频域分析得到跨中（里程688 m）、梁端处（里程100 m）的长波能量聚集的现象，且能量主要聚集在231.7～463.5 m及以上区段；（3）列车敏感波长与轨道主要不平顺能量波长相距较远，故列车在经过此大跨度桥时不会发生明显振动；（4）静态几何形位分析发现轨道不平顺幅值主要发生在跨中（688 m）、桥塔（344 m）区域附近；（5）对轨道动态不平顺进行分析，得到整体升温、整体降温工况下对动态不平顺的影响较大；（6）本研究结果可为大跨桥上无砟轨道优化设计提供参考。更多还原

【Abstract】 Research purposes: With the rapid development of high-speed railways,long-span bridges have been widely used in railways to meet the requirements of line smoothness and the need to span complex terrains.Due to the significant difference in stiffness between ballastless tracks and long-span bridges,problems such as poor adaptability of track structures and poor geometric alignment have emerged. Therefore,ensuring the safe operation of trains on ballastless tracks on long-span bridges has become an important issue at present.This paper took an actual engineering project as the research background and focused on the ballastless track on a long-span cable-stayed bridge with a main span of 688 meters and a designed speed of 160 km/h.It investigated the smoothness of track geometry from multiple dimensions and perspectives,including the frequency domain and time-frequency domain.Research concluions:(1) Frequency domain analysis revealed that the irregularity energy under various operating conditions is primarily concentrated in long-wave frequency bands(wavelengths above 200 meters), with the train exerting the most significant impact on the vertical track alignment at the mid-span of the bridge.(2) Time-frequency domain analysis identified long-wave energy aggregation phenomena at mid-span(mileage 688 m) and beam ends(mileage 100 m), where energy mainly clusters in the wavelength range of 231.7-463.5 m and above.(3) The trainsensitive wavelengths differ significantly from the dominant irregularity energy wavelengths of the track, indicating that trains will not experience noticeable vibrations when traversing this long-span bridge.(4) Static geometric alignment analysis showed that track irregularity amplitudes predominantly occur near mid-span(688 m) and bridge tower regions(344 m).(5) Dynamic irregularity analysis demonstrated that overall temperature rise and drop conditions exert significant impacts on dynamic track irregularities.(6) This study provides valuable references for optimizing the design of ballastless tracks on long-span bridges.更多还原