Failure Behaviour of Bonding Interface for the Continuous Slab Track Structure Under Temperature Load

In order to find out the influence of subgrade frost heave on the deformation of track structure and track irregularity of high-speed railways, a nonlinear damage finite element model for China Railway Track System III (CRTSIII) slab track subgrade was established based on the constitutive theory of concrete plastic damage. The analysis of track structure deformation under different subgrade frost heave conditions was focused on, and amplitude the limit of subgrade frost heave was put forward according to the characteristics of interlayer seams. This work is expected to provide guidance for design and construction. Subgrade frost heave was found to cause cosine-type irregularities of rails and the interlayer seams in the track structure, and the displacement in lower foundation mapping to rail surfaces increased. When frost heave occured in the middle part of the track slab, it caused the greatest amount of track irregularity, resulting in a longer and higher seam. Along with the increase in frost heave amplitude, the length of the seam increased linearly whilst its height increased nonlinearly. When the frost heave amplitude reached 35 mm, cracks appeared along the transverse direction of the upper concrete surface on the base plate due to plastic damage; consequently, the base plate started to bend, which reduced interlayer seams. Based on the critical value of track structures’ interlayer seams under different frost heave conditions, four control limits of subgrade frost heave at different levels of frost heave amplitude/wavelength were obtained.

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.97-98.3 ◽

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.

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Vertical Dynamic Analysis of Ballastless Tracks on Train-Track- Bridge System

MATEC Web of Conferences ◽

10.1051/matecconf/202030602003 ◽

2020 ◽

Vol 306 ◽

pp. 02003

Author(s):

Haoran Xie ◽

Bin Yan ◽

Jie Huang

Keyword(s):

Track Structure ◽

Vertical Acceleration ◽

Train Track ◽

Steel Spring ◽

Slab Track ◽

Ballastless Track ◽

Track System ◽

Train Speed ◽

Track Bridge ◽

Bridge System

In order to investigate the vertical dynamic response characteristics of train-track-bridge system on CWR (Continunously Welded Rail) under dynamic load of train on HSR (High-Speed Railway) bridge. Based on the principle of vehicle train-track-bridge coupling dynamics, taking the 32m simply supported bridge of a section of Zhengzhou-Xuzhou Passenger Dedicated Line as an example, the finite element software ANSYS and the dynamic analysis software SIMPACK are used for co-simulation, and bridge model of the steel spring floating slab track and the CRTSIII ballastless track (China Railway Track System) considering the shock absorbing steel spring, the limit barricade and the contact characteristics of track structure layers are established. On this basis, in order to study the dynamic response laws of the design of ballastless track structure parameters to the system when the train crosses the bridge and provide the basis for the design and construction, by studying the influence of the speed of train on the bridge, the damage of fasteners and the parameters of track structure on the train-track-bridge system, the displacement of rail, vertical vibration acceleration and wheel-rail force response performance are analyzed. Studies have shown that: At the train speed of 40 km/h, the displacement and acceleration of the rail and track slab in the CRTSIII ballastless track are smaller than the floating slab track structure, but the floating slab track structure has better vibration reduction performance for bridges. The acceleration of rail, track slab and bridge increases obviously with the increase of train speed, the rail structure has the largest increasement. Reducing the stiffness of fasteners could decrease the vertical acceleration response of the steel spring floating slab track system, the ability to absorb shock can be enhanceed by reducing the stiffness of the fastener appropriately. Increasing the density of the floating slab can increase the vertical acceleration of the floating slab and the bridge, thereby decreasing the vibration amplitude of the system.

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Influence of age on the detection of defects at the bonding interface in the CRTS III slab ballastless track structure via the impact-echo method

Construction and Building Materials ◽

10.1016/j.conbuildmat.2020.120787 ◽

2020 ◽

Vol 265 ◽

pp. 120787

Author(s):

Wei Jiang ◽

Youjun Xie ◽

Jianxian Wu ◽

Guangcheng Long

Keyword(s):

Bonding Interface ◽

Track Structure ◽

Impact Echo ◽

Ballastless Track ◽

The Impact ◽

Impact Echo Method ◽

Detection Of Defects

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Research on Mechanical Performance of CRTS III Plate-Type Ballastless Track Structure under Temperature Load Based on Probability Statistics

Advances in Civil Engineering ◽

10.1155/2019/2975274 ◽

2019 ◽

Vol 2019 ◽

pp. 1-16 ◽

Cited By ~ 4

Author(s):

Zhiwu Yu ◽

Ying Xie ◽

Xiuquan Tian

Keyword(s):

Tensile Stress ◽

Mechanical Performance ◽

Extreme Values ◽

Maximum Tensile Stress ◽

Maximum Temperature ◽

Daily Maximum Temperature ◽

Daily Maximum ◽

Track Structure ◽

Ballastless Track ◽

Temperature Load

CRTS III (China Railway Track System III) slab ballastless track structure is one of the high-speed railway ballastless track structures which has Chinese independent intellectual property rights. The mechanical performance of CRTS III slab ballastless track structure under temperature load has not been clear yet. Therefore, through temperature field model and temperature load values selected by statistics analysis based on long-term meteorological data, the mechanical performance of ballastless track structure is studied under two typical working conditions with different safety probability. It is found that the daily extreme values of monthly axial uniform temperature and the daily maximum temperature gradient obey certain statistical laws. In addition, the maximum tensile stress of the self-compacting concrete layer is located in the middle and edge of the slab bottom and the side of the slab. The maximum tensile stress of the base plate is located at the edge of the surface of the layer and the inner edge of the limiting groove. The interface normal tensile stress is located at the end and corner of the interface. Furthermore, maximum stress increases with the increase of safety probability.

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Experimental Study of the Influence of Extremely Repeated Thermal Loading on a Ballastless Slab Track-Bridge Structure

Applied Sciences ◽

10.3390/app10020461 ◽

2020 ◽

Vol 10 (2) ◽

pp. 461 ◽

Cited By ~ 1

Author(s):

Lingyu Zhou ◽

Tianyu Wei ◽

Guangchao Zhang ◽

Yingying Zhang ◽

Mahunon Akim Djibril Gildas ◽

...

Keyword(s):

Thermal Loading ◽

Reduction Rate ◽

Railway Track ◽

Track Structure ◽

Structural System ◽

Loading Test ◽

Slab Track ◽

Loading Tests ◽

Three Stages ◽

Track Bridge

To study the initiation and expansion of the interlayer gap of the China Railway Track System Type II (CRTS-II) ballastless slab track structure under the action of repeated thermal loading as well as the influence of the interlayer gap on the displacement, strain and stiffness of the track structure, a 1/4 scale three-span ballastless slab track simply supported bridge structural system specimen was developed and 18 cycles of extremely thermal loading tests were carried out. Static loading tests were carried out before and after the repeated thermal loading test and the effects of the repeated temperature loading on the mechanical properties of the structural system were analyzed. The test results show that under repeated temperature loading, there is a gap between the track slab and cement emulsified asphalt (CA) mortar near the fixed end section of the beam (close to the shear slots). The interlayer gap gradually expands to the mid-span section in a “stepped” shape in three stages: initiation, expansion and stabilization. Under the same temperature load, the camber of the concrete box beam decreases gradually while that of the track structure increases gradually with the increase of the interlayer gap length. During the three stages of interlayer gap development, the track structure stiffness degrades gradually, and the fastest reduction rate during the expansion stage. At the end of the 18th cycle of thermal loading, a degradation of 14.96% and 2.52% is observed in the stiffness of the track structure and that of the ballastless track-bridge structural system, respectively.

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