CRTSⅡ型板式无砟轨道疏控技术方案研究

Research on the Release and Control Technology Scheme of CRTS Ⅱ Track Slab

研究目的:为有效缓解高温作用下Ⅱ型板胀板问题,从源头上削减因轨道板变形受限而形成的温度力,有必要开展Ⅱ型板应力疏控技术方案研究。通过分析桥上和路基无砟轨道结构特点,研究提出连续式无砟轨道单元化和弱纵连方案,运用解析法和有限元法对解锁单元长度、填充材料弹性模量等关键参数进行分析;并基于建立的有限元模型研究单元化后的控制方案,提出轨道板上拱评估方法和限值。研究结论:(1)路基和桥梁地段Ⅱ型板在高温作用下受力特性基本一致,通过解析法分析伤损状态下上拱临界波长为19 m,建议以3块板为一单元进行解锁;(2)分析了宽窄接缝局部和全部填充低弹模高韧性材料弹性模量的影响,采用全填充方案对填充材料弹性模量的取值范围更有利;(3)当轨道板单元化后,均匀植筋更有利于限制高温作用下轨道板的位移;(4)提出了基于轨面高低变化量和轨底-板面高差变化量识别轨道上拱的方法,应重点关注高温季节轨面高低变化量大于2 mm的区段;(5)本研究可为连续式无砟轨道上拱整治提供借鉴和参考。

Research purposes:To alleviate the expansion of CRTSⅡtrack slab under high temperature and reduce the expansion-oriented temperature force caused by the restricted deformation of track slab fundamentally,it is necessary to study the stress-relief technology of CRTSⅡtrack slab in depth.With the analysis of the track-slab structural characteristics in the application scenario of bridge and subgrade,together with the design experience of track slabs in the turnout area,the scheme of continuous track-slab unitization and weak longitudinal connection is proposed.After that,the key parameters are obtained by the analytical method and finite element simulation.Based on the established finite element model,the control scheme after unitization is studied,and the evaluation method together with the allowing superior limit of camber is put forward.Research conclusions:(1)The stress characteristics of CRTSⅡtrack slab in subgrade and bridge section are basically the same under high temperature.The critical wavelength of the camber under damage state is determined as 19 m by the analytical method,and the scheme of three-slab unitization is preferred for unlocking.(2)The influence of partial/full filling in wide-narrow joints on the elastic modulus of low-elastic-modulus high-toughness materials is analyzed.It is concluded that the full filling scheme is more favorable to the value-range selection of filling-material elastic modulus.(3)When the track slab is unitized,the uniform planting of reinforcement is more conducive to limit the movement of track plate under high temperature.(4)The method of identifying track camber on the basis of the height variation of rail surface and the height difference variation of rail bottom slab is proposed.It is found the sections where the height variation of rail surface is greater than 2 mm in high-temperature season should be paid more attention.(5)The research result can provide technical support for camber regulation of continuous slab track.