城市轨道交通路基沉降与无砟轨道轨面不平顺映射关系

Mapping Relationship Between Subgrade Settlement of Urban Rail Transit and Uneven Track Surface of Ballastless Track

路基沉降会影响轨面不平顺,为了分析路基沉降与无砟轨道轨面不平顺间的映射关系,基于温克尔弹性地基耦合梁理论和有限元方法,建立考虑层间接触非线性整体道床轨道梁-体空间有限元模型,对轨道自重荷载和设计列车动荷载作用下轨面不平顺与路基沉降间映射关系展开研究,并在此基础上,提出城市轨道交通无砟轨道线路路基不均匀沉降的安全限值。分析结果表明:路基发生不均匀沉降时,无砟轨道结构在自重荷载和列车动荷载作用下发生跟随性沉降变形,且各层沉降幅值从上到下依次增大;路基沉降幅值越大轨面不平顺越明显,20 m沉降波长条件下,沉降幅值超过25 mm时轨道结构与路基间易形成脱空;轨面不平顺对路基沉降波长也极为敏感,20 mm沉降幅值条件下,当沉降波长超过25 m时路基与轨道结构间脱空现象明显缓解,此时轨面不平顺基本可与路基变形保持一致。

The settlement of subgrade will affect the irregularity of rail surface. In order to analyze the mapping relationship between subgrade settlement and track irregularity of ballastless track, a spatial finite element model of track beam-body of integral ballastless track bed considering layer-to-layer contact nonlinearity is established based on Winkler’s elastic foundation coupling beam theory and finite element method to study the mapping relationship between track irregularity and roadbed settlement under the dead load of track and designed train dynamic load. On this basis, the safety limit of uneven settlement of the subgrade of ballastless track in urban rail transit is put forward. Analysis results show that: when the uneven settlement of subgrade occurs, following settlement deformation of the ballastless track structure takes place under the action of dead weight load and moving load of the train, and the settlement amplitude of each layer increases successively from top to bottom;the larger the settlement amplitude of subgrade, the more obvious the irregularity of rail surface;with 20 m settlement wavelength, it is likely to form a void between the track structure and subgrade when the settlement amplitude exceeds 25 mm;rail surface irregularity is also very sensitive to the settlement wavelength of subgrade;with 20 mm settlement amplitude, void between subgrade and track structure is alleviated obviously when the settlement wavelength exceeds 25 m, while the rail surface irregularity could be basically consistent with the deformation of subgrade.