Design and Analysis of New Elasticity Cushion of Ballastless Track Slab in High-Speed Railway

2010 ◽  
Author(s):  
Lei Yu ◽  
Jiwen Zhang ◽  
Yongming Tu
Keyword(s):  
High Speed ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Track Slab

scholarly journals Mechanical Performance of a Ballastless Track System for the Railway Bridges of High-Speed Lines: Experimental and Numerical Study under Thermal Loading

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2876
Author(s):  
Yingying Zhang ◽  
Lingyu Zhou ◽  
Akim D. Mahunon ◽  
Guangchao Zhang ◽  
Xiusheng Peng ◽  
...  
Keyword(s):  
High Speed ◽  
Thermal Loading ◽  
Mechanical Performance ◽  
Track Structure ◽  
Box Girder ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Track System ◽  
Girder Bridge ◽  
Track Slab

The mechanical performance of China Railway Track System type II (CRTS II) ballastless track suitable for High-Speed Railway (HSR) bridges is investigated in this project by testing a one-quarter-scaled three-span specimen under thermal loading. Stress analysis was performed both experimentally and numerically, via finite-element modeling in the latter case. The results showed that strains in the track slab, in the cement-emulsified asphalt (CA) mortar and in the track bed, increased nonlinearly with the temperature increase. In the longitudinal direction, the zero-displacement section between the track slab and the track bed was close to the 1/8L section of the beam, while the zero-displacement section between the track slab and the box girder bridge was close to the 3/8L section. The maximum values of the relative vertical displacement between the track bed and the bridge structure occurred in the section at three-quarters of the span. Numerical analysis showed that the lower the temperature, the larger the tensile stresses occurring in the different layers of the track structure, whereas the higher the temperature, the higher the relative displacement between the track system and the box girder bridge. Consequently, quantifying the stresses in the various components of the track structure resulting from sudden temperature drops and evaluating the relative displacements between the rails and the track bed resulting from high-temperature are helpful in the design of ballastless track structures for high-speed railway lines.

Research on CRTSIII Ballastless Track Slab Cracks of High-Speed Railway

2013 ◽  
Vol 443 ◽  
pp. 69-73
Author(s):  
Xiang Min Li ◽  
Suo Yan Zhang ◽  
Jun Liu
Keyword(s):  
High Speed ◽  
Comprehensive Investigation ◽  
High Speed Railway ◽  
Main Research ◽  
Structure Characteristics ◽  
Railway Line ◽  
Ballastless Track ◽  
Track Slab

At present ballastless track has been widely applied to railway line for passenger in our country, therefore it has broad prospect. Cracks in ballastless track slabs are inevitable in the construction and operation of high-speed railway. Based on comprehensive investigation of documents, and taking cracks in ballastless track slabs as the main object, systematic and deep research has been done within this paper. The main research contents are as follows: First of all, the structure characteristics of CRTSIII ballastless track in high-speed railway are briefly introduced; Secondly, the paper mostly introduces the impacts what cracks make, the characteristics of cracks and how they form. Subsequently the paper introduces what are made to prevent cracks.

Research on Performance of CRTS I Cement-Emulsified Asphalt Mortar on Site

2017 ◽  
Vol 1142 ◽  
pp. 334-339
Author(s):  
Heng Qiong Jia ◽  
Tao Wang ◽  
Zhao Wei
Keyword(s):  
High Speed ◽  
Pore Diameter ◽  
Woven Fabrics ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Emulsified Asphalt ◽  
Internal Pore ◽  
Ca Mortar ◽  
Asphalt Mortar ◽  
Track Slab

For construction method of infusion bag, expansion of CRTSⅠCA mortar on site by core drilling, water absorption, chloride ion permeability and frost resistance and other properties were studied in comparison with performance of mortar in laboratory under standard curing. The results showed that expansion of the mortar on site was 2%, water absorption was 0.5%, charge amount was 210C, quality loss after 300 freeze-thaw cycles was -1.1%, the performance was much better than molded mortar in laboratory. Pore structure analysis showed that the internal pore diameter of the mortar on site was about 150μm, pore content was 9% to 12%; the internal pore diameter of the mortar in laboratory was also about 150μm, pore content was 10% to 15%. China railway track system（CRTSⅠ）slab ballastless track is one of the main structure forms of the modern high-speed railway and mainly composed of concrete basement, the Cement-emulsified Asphalt Mortar layer and concrete slab, featured by its rapid construction, convenient maintenance, and so on, has been widely applied in high-speed railway construction in our country. The cement-emulsified asphalt（CA） Mortar is one of the key materials and structures in slab ballastless track, providing the appropriate stiffness and elasticity which is usually composed of cement, emulsified asphalt, grit, water and many types of additives, containing a variety of inorganic/organic compositions and many types of surfactants, through the special bag, filling inside the flat cavity by its own weight between track slab and concrete basement with a thickness of 50mm (length×width 4962 mm×2400 mm). The construction method of CA mortar is grouting the non-woven fabrics bag after setting the bag under the track slab fixed by fine adjustment claw, which is convenient and has no requirement of mould removal. The bag is fixed before the perfusion process and does not produce wrinkles. The method greatly enhances the construction efficiency and has been widely utilized in high-speed railway. To full perfusion and tightness with track board, CA mortar contains gas former and expands after the end of infusion in a restricted state. Non-woven fabrics bag itself with breathable permeable, a small amount of water seeps around infusion bags in a period of time after the end of the infusion. Theoretically free water seepage of mortar on the one hand increases the compactness and durability of the mortar, but on the other hand will reduce the mortar expansion; the quality of filling layer mortar can meet the acceptance requirements in the engineering practice. In the same raw materials and mortar mixing, the performance of fresh mortar can require CRTSⅠ type of slab track emulsified asphalt cement mortar in high-speed railway Q / CR 469-2015. After water seepage performance of hardening mortar on site is different from laboratory mortar, because the surface of laboratory mortar is without compression and free deformation. In this paper, contrast mortar on site and molded mortar in laboratory, the performance of hardened mortar on site were studied.

scholarly journals Experimental and Numerical Investigation on Repairing Effect of Polymer Grouting for Settlement of High-Speed Railway Unballasted Track

2019 ◽  
Vol 9 (21) ◽  
pp. 4496 ◽  
Author(s):  
Hongyuan Fang ◽  
Yingjie Su ◽  
Xueming Du ◽  
Fuming Wang ◽  
Bin Li
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Polymer Materials ◽  
Railway Track ◽  
Fe Model ◽  
Cement Slurry ◽  
High Speed Railway ◽  
Application Range ◽  
Ballastless Track ◽  
Track Slab

Uneven settlement of high-speed railway subgrade leads to the irregularity of high-speed railway line, which seriously affects high-speed train operation. The skylight point of high-speed railway operation is short and the maintenance time is limited. Therefore, how to quickly lift and repair the ballastless track slab in the subsidence section is an urgent problem to be solved in the maintenance of high-speed railways. The two-component non-aqueous reactive polymer material has the advantages of strong expansive force, fast reaction speed, and wide application range, which is extremely suitable for the repair of high-speed railway track slab subsidence and lifting. In this study, the expansion force characteristics of different density polymer materials and the stress-deformation curves at corresponding density are tested in laboratory to propose the mechanical parameters of polymer. Then, a three-dimensional finite element (FE) model of high-speed railway train ballastless-track subgrade is established based on ABAQUS. The mechanical characteristics of CRTS III ballastless track under different repair materials, different elevation, and different density of polymer grouting materials are analyzed. The results show that, under the dynamic load of the train, the stress value of polymer repairing material is less than that of cement slurry, presenting a compressive stress state, which is similar to that of the complete subgrade surface. In addition, within a certain thickness range, increasing the thickness of polymer is beneficial to reducing the difference of stress variation between polymer filling layer and complete pavement. Once beyond this range, the thickness of polymer has little effect on the force variation.

scholarly journals Random-Forest Machine Learning Approach for High-Speed Railway Track Slab Deformation Identification Using Track-Side Vibration Monitoring

2021 ◽  
Vol 11 (11) ◽  
pp. 4756
Author(s):  
Gaoran Guo ◽  
Xuhao Cui ◽  
Bowen Du
Keyword(s):  
Random Forest ◽  
High Speed ◽  
Recognition Rate ◽  
Operation Time ◽  
Deformation Monitoring ◽  
Vibration Monitoring ◽  
Railway Track ◽  
Ballastless Track ◽  
Train Operation ◽  
Track Slab

High-speed railways (HSRs) are established all over the world owing to their advantages of high speed, ride comfort, and low vibration and noise. A ballastless track slab is a crucial part of the HSR, and its working condition directly affects the safe operation of the train. With increasing train operation time, track slabs suffer from various defects such as track slab warping and arching as well as interlayer disengagement defect. These defects will eventually lead to the deformation of track slabs and thus jeopardize safe train operation. Therefore, it is important to monitor the condition of ballastless track slabs and identify their defects. This paper proposes a method for monitoring track slab deformation using fiber optic sensing technology and an intelligent method for identifying track slab deformation using the random-forest model. The results show that track-side monitoring can effectively capture the vibration signals caused by train vibration, track slab deformation, noise, and environmental vibration. The proposed intelligent algorithm can identify track slab deformation effectively, and the recognition rate can reach 96.09%. This paper provides new methods for track slab deformation monitoring and intelligent identification.

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