scholarly journals Simulation Study on Vertical Deformation of CRTS III Slab Track under Ambient Temperature and Its Upgrade to “Green Maintenance”

2021 ◽  
Vol 11 (17) ◽  
pp. 7830
Author(s):  
Junzhao Zhou ◽  
Yanyun Luo ◽  
Guosheng Lv ◽  
Yongliang Xiong
Keyword(s):  
Temperature Field ◽  
Temperature Gradient ◽  
Ambient Temperature ◽  
High Speed ◽  
Climatic Conditions ◽  
Vertical Deformation ◽  
Technical Data ◽  
Slab Track ◽  
Ballastless Track ◽  
Elliptical Region

In view of the vertical deformation of CRTS III slab ballastless track of high-speed railways under the action of ambient temperature, a simulation model of the temperature field and vertical deformation of CRTS III slab ballastless track was developed and verified by a field test. The main conclusions are as follows: When the temperature gradient is positive, the central part of the slab track deforms upward. The edge of the slab track deforms downward. The displacement in the central part of the slab track is the largest, and the elliptical region is formed in the middle. The more outward the displacement is, the smaller the displacement is. When the temperature gradient is negative, the downward displacement in the middle of the slab track is the largest, an elliptical region is formed in the middle, and the outward displacement gradually changes from downward to upward. The model developed in this study can accurately reflect the temperature field inside the slab track and the vertical displacement of the slab track at the macro level. In practical application, the technical data can be provided for the maintenance of CRTS III slab tracks according to the simulation results. The temperature field distribution and possible deformation of the slab track can be obtained by adding simulated working conditions according to the climatic conditions. These predictions can be used to focus on targeted maintenance and repair to reduce the investment of human, material, and financial resources, and to achieve the purpose of “green maintenance”.

Study on Spatial Mechanical Characteristic of High-Speed Railway Ballastless Slab Track on Subgrade

2012 ◽  
Vol 503-504 ◽  
pp. 1010-1015 ◽  
Author(s):  
Qing Yuan Xu ◽  
Bin Li
Keyword(s):  
Temperature Gradient ◽  
Mechanical Characteristic ◽  
High Speed ◽  
Three Dimensional ◽  
Calculation Model ◽  
Slab Track ◽  
Combined Load ◽  
Railway Line ◽  
Spring Element ◽  
Ballastless Track

By using beam element to model rail, spring element to model fastener, solid element to model different components of ballastless track, contact element to model the connection between each component of ballastless track, a statics three-dimensional nonlinear finite element mechanical model for calculating the forces transmission among rail, fastening and different component of ballastless slab track on subgrade was established. Experimental data of Suining-Chongqing railway line was given to validate the calculation model. Force of ballastless slab track on subgrade under gravity load, train load, uneven settlement load, temperature gradient load as well as combined load was analyzed. Results show that: spatial forces characteristic of ballastless slab track is very notable under train load; uneven settlement load as well as temperature gradient load has significant influence on the mechanical characteristic of ballastless slab track; force of ballastless slab track increases significantly under combined load than that of under any single load.

scholarly journals Numerical analysis on the time-varying temperature field distribution patterns of ballastless track steel-concrete composite box girders at ambient temperature based on field measurements

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Wangqing Wen ◽  
Shiwei Li ◽  
Aiguo Yan ◽  
Jiahua Zeng
Keyword(s):  
Temperature Field ◽  
Wind Speed ◽  
Ambient Temperature ◽  
High Speed ◽  
Time Varying ◽  
Temperature Field Distribution ◽  
Box Girders ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Main Girder

AbstractTo analyze the time-varying temperature field distribution pattern of ballastless track steel-concrete composite box girders for a high-speed railway at ambient temperature, a numerical model for analyzing the time-varying temperature field of steel-concrete composite box girders was established based on the long-term monitoring data for the internal and external environments of the main girder of the Ganjiang Bridge on the Nanchang-Ganzhou high-speed railway. The influence of factors such as the deck pavement and the ambient wind speed on the time-varying temperature field of the steel-concrete composite box girders were considered. The results showed that there was a significant difference in the vertical temperature gradient patterns on sections at the side web and at the middle web at the same moment in time due to the hindering effect of the track board on the heat exchange between the ambient temperature and the main girder. Increasing the wind speed accelerated the rate of heat exchange between the main girder surface and the environment. In particular, when the internal temperature of the girder was higher than the ambient temperature, the higher the wind speed was, the larger the temperature gradient was. This study lays a foundation for accurate analysis of the structural response of ballastless track steel-concrete composite girder bridges at ambient temperature.

The Calculation of the Supporting Stress of Track Plate in Ballastless High-Speed Rail Structure

2011 ◽  
Vol 97-98 ◽  
pp. 3-9
Author(s):  
Yang Wang ◽  
Quan Mei Gong ◽  
Mei Fang Li
Keyword(s):  
Stress Distribution ◽  
High Speed ◽  
Design Theory ◽  
Moving Load ◽  
Structure Design ◽  
Track Structure ◽  
Beam Model ◽  
High Speed Rail ◽  
Slab Track ◽  
Ballastless Track

The slab track is a new sort of track structure, which has been widely used in high-speed rail and special line for passenger. However, the ballastless track structure design theory is still not perfect and can not meet the requirements of current high-speed rail and passenger line ballastless track. In this paper, composite beam method is used to calculate the deflection of the track plate and in this way the vertical supporting stress distribution of the track plate can be gotten which set a basis for the follow-up study of the dynamic stress distribution in the subgrade. Slab track plate’s bearing stress under moving load is analyzed through Matlab program. By calculation and analysis, it is found that the deflection of track plate and the rail in the double-point-supported finite beam model refers to the rate of spring coefficient of the fastener and the mortar.The supporting stress of the rail plate is inversely proportional to the supporting stress of the rail. The two boundary conditions of that model ,namely, setting the end of the model in the seams of the track plate or not , have little effect on the results. We can use the supporting stress of the track plates on state 1to get the distribution of the supporting stress in the track plate when bogies pass. Also, when the dynamic load magnification factor is 1.2, the track plate supporting stress of CRST I & CRST II-plate non-ballasted structure is around 40kPa.

Numerical Modeling and Simulation Analysis of Temperature Field of Disc Brake on Trains

2011 ◽  
Vol 199-200 ◽  
pp. 1492-1495 ◽  
Author(s):  
Guo Shun Wang ◽  
Rong Fu ◽  
Liang Zhao
Keyword(s):  
Temperature Field ◽  
Temperature Gradient ◽  
High Speed ◽  
Large Scale ◽  
Working Condition ◽  
Constant Speed ◽  
Brake Disc ◽  
Disc Brake ◽  
Brake Pad ◽  
Finite Element Software

The simulation calculation on the temperature field of the disc brake system on high-speed trains under the working condition of constant speed at 50Km/h is made. A steady-state calculation model is established according to the actual geometric size of a brake disc and a brake pad, and the analog calculation and simulation on the temperature field of the brake disc and the brake pad by using the large-scale nonlinear finite element software ABAQUS are carried out. The distribution rules of the temperature field of the brake disc and the brake pad under the working condition of constant speed are made known. The surface temperature of the brake disc at friction radius is the highest, with a band distribution for temperature. There exists a temperature flex point in the direction of thickness, of which the thickness occupies 15% of that of the brake disc; due to the small volume of the brake pad, the temperature gradient of the whole brake pad is not sharp, and larger temperature gradient occurs only on the contact surface.

Temperature Field Analysis on CA Mortar Ballastless Track of High-Speed Railway

2012 ◽  
Vol 531-532 ◽  
pp. 163-167
Author(s):  
Jun Fu ◽  
Yu Qin ◽  
You Yun Yu ◽  
Meng Jun Ye ◽  
Lian Xin Li
Keyword(s):  
Temperature Field ◽  
High Speed ◽  
Theoretical Data ◽  
Element Model ◽  
Field Analysis ◽  
Systematic Research ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Cushion Layer ◽  
Ca Mortar

As an important cushion layer, CA mortar ballastless track is crucial to the durability, safety of high-speed railway and the high-speed railway is influenced by the external environment. The regulation of temperature field evolvement of ballastless track is analyzed in this paper through a two-dimensional, transient finite element model built by ANSYS. The results show that the temperature of structure section caused by solar radiation and circumstances temperature is decreasing along depth in sunlight, and the internal temperature of structure is higher than the surface temperature at night. The integral temperature field of structure reaches the maximum at 1:00 p.m. and the vertical difference of the temperature inside the structure is also the largest, causing the most obvious temperature stress, which provides theoretical data for systematic research on ballastless track of high-speed railway.

Design and Behavior of RPC Slab Track

2014 ◽  
Vol 587-589 ◽  
pp. 1100-1105
Author(s):  
Jian Yang ◽  
Jin Sheng Wang ◽  
Xin Peng
Keyword(s):  
Material Properties ◽  
High Speed ◽  
Optimization Design ◽  
Reactive Powder Concrete ◽  
High Speed Railway ◽  
Slab Track ◽  
Existing Problems ◽  
Ballastless Track ◽  
Reactive Powder ◽  
And Behavior

Reactive Powder Concrete is proposed to be used in the ballastless track for its excellent material properties due to existing problems of high speed railway ballastless track. Three different unit types of RPC frame slab track were proposed through optimization design and the mechanical behavior of these frame slab track was analyzed. The results show that the RPC slab track meet the requirements of bearing capacity, the suggested type of RPC slab track is a frame slab with increased thickness because of its higher techno-economic advantages.

Experimental Study on Vertical Stiffness of WJ-8 Fastener for High-Speed Railway

2015 ◽  
Vol 723 ◽  
pp. 100-103 ◽  
Author(s):  
Can Liu ◽  
Zhi Ping Zeng ◽  
Jia Yu Yuan ◽  
Bin Wu ◽  
Kun Teng Zhu
Keyword(s):  
High Speed ◽  
Plate Theory ◽  
Vertical Displacement ◽  
Track Structure ◽  
Static Stiffness ◽  
Analysis Model ◽  
Element Analysis ◽  
Vertical Stiffness ◽  
Slab Track ◽  
Ballastless Track

The rail vertical displacement of CRTSII slab track structure under vertical static loads was analyzed in this paper by using 1:1 full-scale track model, based on which the WJ-8 fastener vertical static stiffness was calculated, and the rationality of the fastener vertical stiffness values and the relationship between the values and load were studied. According to the beam-plate theory and beam-solid theory for slab ballastless track, a finite element analysis model of CRTSII slab track structure was established. The rail vertical displacement under the same case as test was calculated by using the measured fastener vertical stiffness value. The rationality of the method for testing and the fastener vertical static stiffness is verified through comparing the calculated values with experimental ones.

Influences of CA Mortar Elastic Modulus on Stress and Deformation of Slab Track in High Speed Railway

2011 ◽  
Vol 197-198 ◽  
pp. 1480-1485 ◽  
Author(s):  
Rong Chen ◽  
Wang Ping ◽  
Zhe Liu
Keyword(s):  
Elastic Modulus ◽  
Temperature Gradient ◽  
High Speed ◽  
Plate Theory ◽  
Base Plate ◽  
High Speed Rail ◽  
Slab Track ◽  
The Common ◽  
Ca Mortar ◽  
Track Slab

CA mortar is a key component of slab track. It is used as the material for leveling damping structure layer between the rigid track slab and concrete trackbed of slab track in high speed rail. In order to determine functions of CA mortar with low elastic modulus (EM), the beam/plate theory on elastic foundation was applied to the calculation of slab track’s stress. Under the bonding or no-bonding condition, the influence of CA mortar’s EM on the warping stress and displacement of track slab were calculated. Stress distribution of CA mortar under the common effects of train load and temperature gradient was explored, and the intensity requirement of CA mortar with different EM was put forward. Calculation results show that longitudinal and lateral bending moments of base plate both increase with the increasing of CA mortar’s EM; when the CA mortar’s EM is in the range of 50～10000MPa, there is gap between track slab and the mortar and the deformation of CA mortar (50mm thick) is not enough to compensate the warpage of the track slab; with the increasing of CA mortar’s EM, the tensile and compressive stresses of CA mortar both increase under the common effects of train load and temperature gradient, thus higher requirements on tensile and compressive strength are demanded when CA with high elastic modulus is used.

Deformation Monitoring and Evaluating Technology for Subgrade of Unballasted Track on Lan-Xin Passenger Dedicated Line

2013 ◽  
Vol 351-352 ◽  
pp. 1152-1158
Author(s):  
Qian Su ◽  
Wen Chao Zhang ◽  
Li Song Zhang ◽  
Jian Zhang
Keyword(s):  
High Speed ◽  
Assessment Method ◽  
Climatic Conditions ◽  
Deformation Monitoring ◽  
Ballastless Track ◽  
Road Section ◽  
Gravel Soil ◽  
Ultimate Settlement ◽  
Hyperbolic Method ◽  
Passenger Dedicated Line

Lanzhou-Xinjiang passenger dedicated line is the first high speed railway on chinas northwestern Gobi where the temperature range is large and the wind is huge. Most road section of Lan-Xin passenger dedicated line is subgrade. This paper researches the ballastless track subgrade settlement observation scheme and assessment method on area where climatic conditions is harsh and geologic conditions is complex. The result shows that: the observation accuracy of subgrade settlement tests satisfies the requirement by using Layered settlement instrument, intelligent static force level and high-accuracy Hydraulic settlement instrument; Subgrade lies upon bedrock or Gobi soil with great bearing capacity in gale area, and distance between observation sections could be increased seemly. The space between observation sections generally should be less than 100m in areas where bedrock exposed, thick gravel soil distribute commonly; the distance between observation sections should be less than 50m in pre-mountain Alluvial-pluvial plain areas; hyperbolic method adapt the estimate of subgrade settlement on Gobi area, and the correlation coefficient is 0.97; Subgrade settlement deformation curve converges quickly and the settlement value after 40 days reaches 85% of ultimate settlement.

Ensuring electrical safety of power supply systems of electrified AC railways for highspeed lines

2018 ◽  
Vol 77 (6) ◽  
pp. 337-346 ◽  
Author(s):  
A. B. Kosarev ◽  
A. V. Barch ◽  
E. N. Rozenberg
Keyword(s):  
Power Supply ◽  
High Speed ◽  
Structural Features ◽  
Electrical Safety ◽  
Safe Operation ◽  
Ballastless Track ◽  
Conventional Structure ◽  
Artificial Earth ◽  
Earth Connection ◽  
Supply Systems

Abstract. High-speed railways are fast-growing and promising type of traffic. In Russia development of high-speed railway service is associated with the solution of a number of problems, including infrastructure. Authors propose to use earth connection of the railway catenary with the help of an artificial earthing switch on currently designed high-speed line Moscow—Kazan for 2×25 kV power supply system. Taking into account requirements for electrical safety conditions for maintenance of the track and earthed catenary supports, paper justifies method for calculating allowable voltages of rail—earth points and supports of catenary. Methods takes into account structural features of ballastless track superstructure used for high-speed lines. It is estimated that the voltages admissible under the electrical safety conditions are random in nature and distributed logarithmically normal. When calculating probability of safe operation, one should take into account random nature of both permissible stresses and those actually occurring on the track. It is estimated that the probability of safe operation in traction networks of sections with ballastless track superstructure does not exceed a similar value in electrified sections with the conventional structure of a ballast prism. Feasibility of using a 2×25 kV earth system using an artificial earth connection is confirmed, recommendations on its use are given. Authors substantiate allowable values of the rail—earth voltage and catenary supports, which practically exclude the occurrence of hazardous situations for personnel maintaining the track in sections with ballastless track superstructure.

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