Dynamic responses of bridge-approach embankment transition section of high-speed rail

By using the transient finite element method, a three-dimensional wheelset-track coupled rolling contact model for high-speed rail is established, and the rationality and effectiveness of the model are verified by field measurements. Next, the wheel-rail contact stress states and relative slip characteristics are calculated and analyzed to reveal the cause of inner rail corrugation. Then, the vertical vibration acceleration of the rail/wheel is taken as the output variable to study the dynamic responses of the wheelset-track system. Finally, the parameter sensitivity analysis is carried out. The results show that the maximum normal/tangential contact stress between the inner wheel and inner rail is greater than that between outer wheel and outer rail due to the unbalanced load of inner rail caused by the excess superelevation of track structure, which indicates that the unbalanced load of the inner rail may aggravate the development of rail wear, and the rationality of the model established in this paper is verified. The wheel-rail relative slip region on the inner rail side appears periodically, and the distance between the two adjacent slip regions is close to the characteristic wavelength of the measured inner rail corrugation, which illustrates that the periodic variation of slip regions on the inner rail surface plays an important role in the formation of rail corrugation, and the validity of the model is verified. The periodic distribution of wheel-rail relative slip regions on the outer rail surface is not obvious, demonstrating that the outer rail tends to form uniform wear, which is consistent with the fact that the outer rail corrugation is slight in the measured section. The wheelset-track system has been in the process of unstable continuous oscillation in the analysis interval, combined with the analysis results of the wheel-rail relative slip characteristics, it can be concluded that the unstable self-excited vibration of wheelset-track system under the condition of tangential contact force reaching saturation is the main cause of rail corrugation. The dominant characteristic frequencies of vertical vibration accelerations of rail and wheel are all 561 Hz, the corresponding characteristic wavelength (148 mm) is close to the distance (150 mm) between the calculated adjacent slip regions, and is also close to the characteristic wavelengths (125 mm and 160 mm) of inner rail corrugation, which shows that the resonance phenomenon occurs in the wheelset-track system at the above frequency, thus leading to the increase of dynamic responses of wheelset-track system. The fastener vertical stiffness and wheel-rail coefficient of friction have significant effect on the development of rail corrugation, and the running speed determines the occurrence probability of inner/outer rail corrugation by affecting the track superelevation state.

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Impact Analysis of Track Irregularity in Transition Section of High Speed Rail

Proceedings of the Second International Conference on Railway Technology: Research, Development and Maintenance ◽

10.4203/ccp.104.224 ◽

2014 ◽

Cited By ~ 1

Author(s):

H.W. Yang ◽

D. Chu ◽

I.C. Wang ◽

C.F. Hung ◽

S.K. Ho

Keyword(s):

High Speed ◽

Impact Analysis ◽

High Speed Rail ◽

Transition Section ◽

Track Irregularity

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Numerical Investigation on Dynamic Performance of a Bridge-Tunnel Transition Section with a Deep Buried Pile-Plank Structure

Advances in Civil Engineering ◽

10.1155/2020/8885535 ◽

2020 ◽

Vol 2020 ◽

pp. 1-16

Author(s):

Shuanglong Li ◽

Limin Wei ◽

Xiaobin Chen ◽

Qun He

Keyword(s):

Transition Zone ◽

High Speed ◽

Dynamic Responses ◽

Mountainous Area ◽

Constant Length ◽

Transition Section ◽

Tunnel Transition ◽

Track Stiffness ◽

Varying Length ◽

Common Transition

To address the track irregularity at transition zones between subgrade and rigid structures (bridge, tunnel, etc.), some common transition approaches, such as trapezoid subgrade, were adopted in many engineering areas. However, in regard to a mountainous area, the common transition approaches may not be practicable anymore due to the limitation of the length between subgrade and rigid structures. In this paper, a new type of bridge-tunnel transition section with a deeply buried pile-plank structure (DBPPS) for short-distance transition is introduced. A three-dimensional finite element model that considers vehicle-track-subgrade coupling vibration is proposed to study the dynamic performances of a DBPPS transition section in the Shanghai–Kunming high-speed railway. With this model that has been validated with measured responses from field tests, the dynamic responses and the smoothness in track stiffness along the transition zone are analyzed. In addition, the influences of train speed, axle load, and train direction on dynamic responses are investigated, and the influences of two optimization strategies, including varying-length piles and constant-length piles, on the stiffness smoothness of the DBPPS transition section are discussed. Results show that the vibration level of the DBPPS transition section is lower than that of the abutment and the tunnel, and the additional load caused by vertical track stiffness difference aggravates the vibration at the connections between the DBPPS transition section and the abutment (or tunnel). Furthermore, the smoothness in stiffness along the transition zone can be significantly improved by the improvement strategy with varying-length piles.

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Taiwan High Speed Rail Viaducts: A Seismic-Safety and Passenger-Comfort Design Approach

2010 Joint Rail Conference, Volume 1 ◽

10.1115/jrc2010-36129 ◽

2010 ◽

Author(s):

S. H. Cheng ◽

Tony Yen ◽

S. C. Huang

Keyword(s):

High Speed ◽

Design Method ◽

Dynamic Responses ◽

Dynamic Interactions ◽

High Speed Rail ◽

Seismic Safety ◽

Passenger Comfort ◽

Detail Design ◽

Earthquake Zone ◽

Local Code

The Taiwan High Speed Rail (HSR) line, running north ∼ south, is located at the western corridor of the island with a total length of 345 km., out of which 252 km. are continuous viaducts or bridges. This type of structure was chosen to eliminate on grade crossing for trains travelling at speed of 300 km/hr., this will also allow better land usage on either side of the line. Taiwan is a major earthquake zone, the imperative challenge for the planning and design of this world’s longest HSR viaducts is to provide controlled dynamic responses to the structure for operational safety and passenger comfort. To achieve this goal, dynamic interactions between the running high speed trains and the viaducts need to be studied comprehensively and in details. The result is a specification very different from traditional railway viaduct. SINOTECH Engineering Consultant, Ltd. was involved with this HSR project in various stages including planning for part of the alignment during project development by government agencies, and also basic and detail design of viaducts for the BOT concessionaire THSRC. In this paper an introduction is given on how the major contents of viaduct specific design specification of UIC, Eurocode, Japanese code and Taiwan local code have been combined. How Sinotech approached this challenge, the design method chosen, and a summary of bridge design related to seismic safety and passenger comfort are also described herewith. Finally, the experience gained from Taiwan HSR and suggestions for future HSR design and construction are summarized for the reference of similar projects in the future.

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ANALYSIS OF HIGH-SPEED RAIL ACCOUNTING FOR JUMPING WHEEL PHENOMENON

International Journal of Computational Methods ◽

10.1142/s021987621343007x ◽

2014 ◽

Vol 11 (03) ◽

pp. 1343007 ◽

Cited By ~ 20

Author(s):

KOK KENG ANG ◽

JIAN DAI ◽

MINH THI TRAN ◽

VAN HAI LUONG

Keyword(s):

High Speed ◽

Computational Study ◽

Dynamic Responses ◽

Contact Model ◽

High Speed Train ◽

Train Track ◽

Hertz Contact ◽

High Speed Rail ◽

Track System ◽

Hertz Contact Model

In this paper, a computational study using the moving element method (MEM) was carried out to investigate the dynamic response of a high-speed train–track system. Results obtained using Hertz contact model and linearized Hertz contact model are compared and discussed. The dynamic responses of a train travelling across a uniform foundation and a transition region are also investigated. Parametric study is performed to understand the effect of various factors on the occurrence and patterns of the jumping wheel phenomenon such as the variation of foundation stiffness, travelling speed of the train and the severity of railhead roughness.

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Discrete Element Modeling of Full-Scale Ballasted Track Dynamic Responses from an Innovative High-Speed Rail Testing Facility

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198119846475 ◽

2019 ◽

Vol 2673 (9) ◽

pp. 107-116 ◽

Cited By ~ 1

Author(s):

Bin Feng ◽

Eun Hyun Park ◽

Haohang Huang ◽

Wei Li ◽

Erol Tutumluer ◽

...

Keyword(s):

Physical Model ◽

Dynamic Loading ◽

High Speed ◽

Discrete Element ◽

Full Scale ◽

Dynamic Responses ◽

Particle Simulation ◽

High Speed Rail ◽

Ballasted Track ◽

Dem Model

To achieve increased rail network safety and reliability, it is important to better understand ballast layer performance under complex and demanding dynamic loading field scenarios, especially for high speed lines on ballasted track. Repeated high-speed loading tests were recently conducted at three train speeds on a full-scale ballasted track-subgrade system, known as the Zhejiang University innovative high-speed rail tester (ZJU-iHSRT). BLOKS3D, a polyhedral discrete element method (DEM) particle simulation code with newly featured parallel computing capability, was used to capture the full-scale ballasted track dynamic responses at those speeds. A proportional–integral–derivative controller was also implemented in the DEM code to ensure identical dynamic loadings were applied in the DEM model as in the physical model. This paper presents the dynamic response findings obtained using the DEM model: 1) Crosstie vibration velocities captured in the DEM model match closely with the measurement obtained from the same crosstie in the physical model; 2) ballast particle vibration velocities recorded in the DEM model provide an overall good match with the data measured from the same location in the physical model; and finally, 3) visualized macroscopic ballast layer dynamic responses reveal the mechanical behavior of the ballast layer under dynamic loading scenarios applied in the ZJU-iHSRT full-scale ballasted track-subgrade system.

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