摘要
针对土质路基上双块式无砟轨道典型结构,分别建立Winkler弹性地基叠合梁解析模型和考虑层间接触非线性的轨道-路基空间有限元模型,对路基不均匀沉降引起的无砟轨道轨面几何变形特征及其与路基沉降波长、幅值之间的对应关系开展了研究。结果表明:余弦型路基不均匀沉降向上传递至轨面时,变形形式基本不变,在沉降边缘区域钢轨存在微小的局部上拱,变形范围相对于路基有所扩散;轨面几何变形曲线可由波长、波深和局部上拱幅值3项特征确定,且各项特征受路基不均匀沉降波长和幅值的综合控制,均可描述为路基沉降波长和幅值的函数;当路基不均匀沉降较平缓时,上部轨道与路基结构能保持较高的跟随性,轨面与路基变形差异很小;随着沉降幅值增大或范围缩小,双块式无砟轨道因较强的整体性而极易与路基表面出现离缝,轨道结构与路基之间会形成明显的沉降差,此时,轨面不平顺和轨下空吊同时存在,给无砟轨道的服役寿命和列车的安全平稳运营造成隐患。
In view of the typical structure of double-block ballastless track system on the soil subgrade, both an- alytical model of a composite beam on the Winkler elastic foundation and a spatial finite element model with the contact nonlinearity taken into account were established, to analyze the characteristics of rail deflection induced by the uneven subgrade settlement, as well as the corresponding relationship between rail deflection and the wavelength and amplitude of subgrade settlement. Results showed that, when the uneven settlement of a cosine-type subgrade was transferred to the surface of the rail, the pattern of the rail deflection basically remained unchanged. Only tiny local arches appeared on the rail at the edges of the settlement, with the range of rail deflection slightly larger than that of the subgrade. The rail deflection curve can be determined by three factors： the wavelength, the depth and the arch amplitude. These factors were significantly affected by the amplitude and wavelength of the uneven subgrade settlement and they can be described as a function of the wavelength and amplitude of the subgrade settlement. When the uneven settlement curve of the subgrade was gentle, the deflection of track structure was in accordance with the subgrade. With the increase of amplitude or the decrease of wavelength of subgrade settlement, voids between the supporting layer of the track and the upper layer of the subgrade may be generated on account of the high integrity of the double-block ballastless track structure.The settlement difference between the track structure and the subgrade may be formed. As a result, the rail ir- regularity and the void of track structure may take place simultaneously, which pose a threat to the operation quality of the train and the service life of the track.
出处
《铁道学报》
EI
CAS
CSCD
北大核心
2016年第9期92-100,共9页
Journal of the China Railway Society
基金
国家重点基础研究发展计划(973计划)(2013CB036205
2013CB036206)
中国铁路总公司科技研究开发计划(2014G001-1)
中央高校基本科研业务费(2682015CX045)
国家自然科学基金(51478397)
