| Ballastless track has become the main track type of newly built high speed railway lines due to its many advantages in recent years. According to the short period and large scale of high speed railway construction in China, the accumulated experience of ballastless track construction and design is limited, and studies of ballastless track service performance under complicate conditions is also limited, which leads to occurrence of varying degrees of diseases in many high speed lines after operation.This paper heading from ballastless track design concept, a refinement analytical ballastless track model is proposed by means of design and checking method innovation and field tests of detailed parameters, model application of ballastless track design, checking and disease analysis process is also discussed in this paper. The refinement analytical ballastless track models consist of ballastless track spatial design model, prestressed reinforcement checking model and refined model of interlayer disease analysis. In summary, the study of this paper are summarized as follows:(1) Research of main parameter collection and detailed parameter field tests required in refined modeling process.Existing structural dimension and material parameters of currently widely used slab track is collected in this paper, then the main parameters of different type slab track is established.Address the detailed parameters needed in refined modelling process such as friction coefficient of sliding layer, bonding properties between bedplate and subgrade surface, dowel limiting ability. Test method is designed and field test have been taken, a large number of detailed parameters are acquired, which laid the foundation of refined ballastless track analysis model.(2) Modelling research of ballastless track spatial design model and its application research.Using refined analysis concept, a spatial design model of ballastless track is established, considering some detailed parameters such as solid element effect of different ballastless track layers, interlayer interactions and restrain mode. Internal forces and moments of spatial model have been quickly and accurately extracted by means of existing software secondary development, the extraction method of internal forces and moments have been theoretically validated. This method provides a tool for achieving ballastless track spatial design.Take the typical multilayer ballastless track system-CRTS II Slab track for example, the beam-plate-plate model and spatial analysis models established in this paper were compared, Unitary slab track warping characteristics and internal temperature force under temperature gradient is also analyzed which is unable to be analyzed by using beam-plate-plate model. Then the reliability and advantages of spatial design model have been described after all. Longitudinal force transmission system of longitudinal connected slab track at transition section is studied by using spatial design model, some ballastless track transition section setting mode have been proposed.(3) Modelling research of ballastless track prestressed reinforcement checking model and effects evaluation work of prestressing tendons damage.Prestressed reinforcement is introduced into refined ballastless track analysis model, modelling method of prestressed reinforcement checking model is introduced and calculation result of ballastless track pre-pressure and designed pre-pressure value are contrasted, the reliability of prestressed reinforcement model in this paper can be verified. Detailed study of the force and deformation characteristics of currently promoted CRTS III slab track under prestressing loads have been carried out, force and deformation characteristics of ballastless track under prestressed reinforcement coupling with vehicle, temperature and other loads have also been analyzed.According to CRTS I track slab prestressed reinforcement prestressing tendons damage during high-speed railway operation, the additional load of track slab caused by prestressing tendons damage in different locations and different numbers and its affection to interlayer stress have been analyzed and evaluated.(4) Modelling research of refined interlayer disease analysis model and separation generation and evolution process of CA motor layer-track slab and bedplate-subgrade surface.According to the characteristics of ballastless track disease mostly occurs between interlayers, a refined interlayer disease analysis model has been built in which interlayer separation generation and evolution process can be simulated. The model is validated by single sleeper lifting test, the reliability of the model can be described.Take advantage of CA motor layer-track slab separation analysis model of CRTS â…¡ slab track, separation growth law under temperature gradient incensement in different interlayer bonding strength have been studied.Critical temperature gradient of separation generation and separation cut through under different interlayer bonding strength have been analyzed, interlayer separation depth evolution process have also been analyzed, thus interlayer separation generation and evolution law have been carefully studied. According to the relevant provisions of current temperature gradient, thus the reasonable design range of interlayer bonding strength is finally suggested. Take advantage of bedplate-subgrade surface separation analysis model of CRTS II slab track, bedplate-subgrade surface separation growth related with foundation uneven settlement under different interlayer bonding strength have been studied.Settlement value with respect to interlayer initial separation and cutting through separation under single cosine settlement wave and half-cosine Stepped settlement wave have been analyzed, thus the reasonable design range of bedplate-subgrade surface interlayer bonding strength is finally suggested.The refined analysis concept proposed in this paper is helpful to promote ballastless track design and checking methods development, and it is also helpful to improve the accuracy of ballastless track design. The detailed parameters obtained by field test in this paper also provides a basis for ballastless track future design.The refined interlayer disease analysis model can be a reliable tool to analysis ballastless Track disease generation mechanism and evolution law, thus providing a theoretical basis for the ballastless track disease remediation. In summary, the refined spatial analysis methods proposed in this paper will provide a brand new idea and method to develop and optimize ballastless track system in the future. |
