Study On Selection Of Unballasted Track In Heavy Haul Railway Tunnel

Heavy-haul railway ballasted track structure requires lots of track maintenance work and large tunnel cross-section. These shortcomings can be well overcome by using unballasted track. So a study on unballasted track in heavy-haul railway is needed. This article’s main research work and conclusions are as follows:(1) A Static and Dynamic Calculating Model of Heavy-haul Railway Unballas ted Track Was EstablishedA three-dimensional coupling solid model was established, which can accurate ly simulate mechanical properties of unballasted track.A train-track-tunnel coupling dynamics model was established. On the one ha nd, car body model was refined. And a three-piece Bogie model was established. On the other hand, a tunnel model with filling layer, invert, arch wall, shotcre te layer and surrounding rock was established. The contrast with measured data proved the reliability of this calculation method. The model provided a effective way of heavy-haul railway unballasted track dynamic analysis.(2) A Study Was Done on the Selection of Heavy-haul Railway Unballasted T rack from the Perspective of Static and DynamicOn the foundation of systemic analysis on the static and dynamic characterist ics of CRTS Ⅰ plate-type ballastless track, CRTS Ⅰ double-block ballastless track,l ow vibration track (LVT), and long elastic sleeper ballastless track, a conclusion was drawn as follows:①CRTS Ⅰ plate-type ballastless track is not recommended, as temperature gradient at tunnel portals may cause large longitudinal displacem ent of structure, warp deformation of the track slab, high local stress in the road bed, and relatively large shear stress in the raised block.②CRTS Ⅰ double-block ballastless track is also not recommended, as the sleeper-roadbed interface is eas y to failure.③Long elastic sleeper ballastless track is recommended, as it has s maller stress, acceleration, fastener counterforce, and track gauge variation under dynamic loading.④Low vibration track can also be used, yet the control of tran sverse displacement of sleepers and gauge should be paid attention to.(3) A Study Was Done on the Reasonable Value of Long Elastic Sleeper Ball astless Track Design Parameters A study was done on the reasonable value of fastener vertical stiffness and r ubber coat boot elastic modulus. Through analysis, suggestions were put forward as follows:The vertical stiffness of fasteners should be improved properly, or consider using type II or type III elastic rod fastener. The elastic modulus of ru bber coat boot is suggested to be40MPa-60MPa.