Modelling the Long-Term Behaviour of a High-Speed Railway Transition Zone Using a Lumped Parameter Track Model

2021 ◽  
pp. 1234-1241
Author(s):  
Ilaria Grossoni ◽  
Samuel Hawksbee ◽  
Pedro Jorge ◽  
Yann Bezin
Keyword(s):  
Transition Zone ◽  
High Speed ◽  
High Speed Railway ◽  
Lumped Parameter

How to balance interfirm relationships? A case from high-speed railway industry

2020 ◽  
Vol 35 (11) ◽  
pp. 1785-1799 ◽  
Author(s):  
Na Zhang ◽  
Xiaopeng Deng ◽  
Bon-Gang Hwang ◽  
Yanliang Niu
Keyword(s):  
High Speed ◽  
Superior Performance ◽  
Interfirm Relationships ◽  
High Speed Railway ◽  
Content Type ◽  
Railway Industry ◽  
Interfirm Cooperation ◽  
Relationship Structures ◽  
Interfirm Competition

Purpose Balancing interfirm relationships is important for firms’ long-term superior performance. However, prior studies mainly focus on interfirm competition or interfirm cooperation separately, ignoring the balance of interfirm relationships. To bridge this gap in knowledge, this study aims to develop a framework to evaluate the balance of interfirm competition and interfirm cooperation and propose strategies to optimize a firm’s interfirm relationships. Design/methodology/approach After an in-depth literature review, a framework was developed for evaluating and optimizing the interfirm relationships. Taking the high-speed railway industry as an example, the proposed framework was implemented. Findings The results of the case confirm that the balancing of interfirm relationships can lead to more superior firm performance. Also, rather than mutual suppression, the interfirm competition and interfirm cooperation present a roughly positive relationship. Originality/value This study would contribute to the existing knowledge body by developing a framework for balancing interfirm relationships. Also, this study can aid practitioners in evaluating and optimizing their interfirm relationship structures.

scholarly journals Fatigue Life Characteristics of Segmental Lining Structure for the Shallow Buried Metro Tunnel under the Dynamic Load of a High-Speed Railway

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Wangping Qian ◽  
Taiyue Qi ◽  
Qing Zhao ◽  
Bingrong Pu ◽  
Jin Zhang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fatigue Failure ◽  
Dynamic Load ◽  
High Speed ◽  
Dynamic Loads ◽  
High Speed Railway ◽  
Segmental Lining ◽  
Lining Structure ◽  
Metro Tunnel

Shallow buried shield metro tunnels constructed underneath subgrade project of high-speed railways are becoming increasingly common in China, but the lower metro tunnel bears the fatigue effect of dynamic load induced by the upper high-speed railway, so the long-term durability of segmental lining is a nonnegligible problem. The segmental lining structure of metro tunnel is in a state of static-dynamic loads for a long time, especially when a high-speed railway passes above the metro line, and the long-term durability of segmental lining needs further research. Based on theoretical analysis, the effect of different forms of loads on the fatigue life was analyzed, the change law of the static-dynamic loads on segmental lining was summarized, and the method was put forward to evaluate the fatigue life characteristics of segmental lining. The research results reveal that the additional dynamic load is the fundamental reason for the fatigue failure of the structure, and the existence of static load can cause and accelerate the occurrence of structural fatigue failure simultaneously. The results indicate that the fatigue life decreases gradually with the increase of static-dynamic load. Based on coupling analysis of static-dynamic loads of segmental lining, the fatigue life increases first and then decreases with the increase of buried depth of metro tunnel, and it remains unchanged when the depth exceeds a certain value. According to the actual metro tunnel engineering, by using ABAQUS software, a three-dimensional numerical simulation was carried out to analyze the characteristics of the fatigue life and evolution rules of segmental lining. Based on the modified fatigue life formula and metro service life, the optimization design of the buried depth was carried out to determine the most reasonable range of the buried depth. This study provides a valuable reference for safe operation and long-term durability of metro tunnels under high-speed railways.

scholarly journals Evolution of Rheological Behaviors of Styrene-Butadiene-Styrene/Crumb Rubber Composite Modified Bitumen after Different Long-Term Aging Processes

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2345 ◽  
Author(s):  
Yangsheng Ye ◽  
Gang Xu ◽  
Liangwei Lou ◽  
Xianhua Chen ◽  
Degou Cai ◽  
...  
Keyword(s):  
Low Temperature ◽  
High Speed ◽  
Crumb Rubber ◽  
Modified Bitumen ◽  
High Speed Railway ◽  
Modified Asphalt ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
Butadiene Styrene

In this study, a new type of composite modified bitumen was developed by blending styrene-butadiene-styrene (SBS) and crumb rubber (CR) with a chemical method to satisfy the durability requirements of waterproofing material in the waterproofing layer of high-speed railway subgrade. A pressure-aging-vessel test for 20, 40 and 80 h were conducted to obtain bitumen samples in different long-term aging conditions. Multiple stress creep recovery (MSCR) tests, linear amplitude scanning tests and bending beam rheometer tests were conducted on three kinds of asphalt binders (SBS modified asphalt, CR modified asphalt and SBS/CR composite modified asphalt) after different long-term aging processes, including high temperature permanent deformation performance, resistance to low temperature thermal and fatigue crack. Meanwhile, aging sensitivities were compared by different rheological indices. Results showed that SBS/CR composite modified asphalt possessed the best properties before and after aging. The elastic property of CR in SBS/CR composite modified asphalt improved the ability to resist low temperature thermal and fatigue cracks at a range of low and middle temperatures. Simultaneously, the copolymer network of SBS and CR significantly improved the elastic response of the asphalt SBS/CR modified asphalt at a range of high temperatures. Furthermore, all test results indicated that the SBS/CR modified asphalt possesses the outstanding ability to anti-aging. SBS/CR is an ideal kind of asphalt to satisfy the demand of 60 years of service life in the subgrade of high speed railway.

scholarly journals Full-scale multi-functional test platform for investigating mechanical performance of track–subgrade systems of high-speed railways

2020 ◽  
Vol 28 (3) ◽  
pp. 213-231
Author(s):  
Wanming Zhai ◽  
Kaiyun Wang ◽  
Zhaowei Chen ◽  
Shengyang Zhu ◽  
Chengbiao Cai ◽  
...  
Keyword(s):  
High Speed ◽  
Mechanical Performance ◽  
Full Scale ◽  
Functional Test ◽  
Railway Track ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Railway Infrastructure ◽  
Test Platform

Abstract Motivated by the huge practical engineering demand for the fundamental understanding of mechanical characteristics of high-speed railway infrastructure, a full-scale multi-functional test platform for high-speed railway track–subgrade system is developed in this paper, and its main functions for investigating the mechanical performance of track–subgrade systems are elaborated with three typical experimental examples. Comprising the full-scale subgrade structure and all the five types of track structures adopted in Chinese high-speed railways, namely the CRTS I, the CRTS II and the CRTS III ballastless tracks, the double-block ballastless track and the ballasted track, the test platform is established strictly according to the construction standard of Chinese high-speed railways. Three kinds of effective loading methods are employed, including the real bogie loading, multi-point loading and the impact loading. Various types of sensors are adopted in different components of the five types of track–subgrade systems to measure the displacement, acceleration, pressure, structural strain and deformation, etc. Utilizing this test platform, both dynamic characteristics and long-term performance evolution of high-speed railway track–subgrade systems can be investigated, being able to satisfy the actual demand for large-scale operation of Chinese high-speed railways. As examples, three typical experimental studies are presented to elucidate the comprehensive functionalities of the full-scale multi-functional test platform for exploring the dynamic performance and its long-term evolution of ballastless track systems and for studying the long-term accumulative settlement of the ballasted track–subgrade system in high-speed railways. Some interesting phenomena and meaningful results are captured by the developed test platform, which provide a useful guidance for the scientific operation and maintenance of high-speed railway infrastructure.

Long term evolution in high speed railway environments: Feasibility and challenges

2013 ◽  
Vol 18 (2) ◽  
pp. 237-253 ◽  
Author(s):  
Jaime Calle-Sanchez ◽  
Mariano Molina-Garcia ◽  
Jose I. Alonso ◽  
Alfonso Fernandez-Duran
Keyword(s):  
High Speed ◽  
Long Term Evolution ◽  
High Speed Railway ◽  
Term Evolution

scholarly journals Vibration and Long-Term Performance Analysis of Pile-Plank-Supported Low Subgrade of Ballastless Track under Excitation Loads

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Junjie Huang ◽  
Qian Su ◽  
Ting Liu ◽  
Xun Wang
Keyword(s):  
High Speed ◽  
Experimental Results ◽  
Soft Ground ◽  
Board Structure ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Long Term Performance ◽  
Term Performance ◽  
Frequency Sweeping

Pile-plank structures are widely applied for high-speed railway built in soft ground in China. It can be used as a reinforcement to improve the behavior of subgrade by providing vertical confinement to increase their stiffness and strength and reduce the subgrade settlement of ballastless track. However, the use of pile-board structure for soft ground reinforcement of high-speed railway is hindered by the existing gap between applications and theories. To verify vibration characteristics and long-term performance of pile-plank-supported low subgrade of ballastless track and the benefit of pile-board structure, an experimental study was conducted on low subgrade of pile-board under excitation loads using both in situ frequency sweeping and cyclic loading experiments. The frequency sweeping experimental results show that the pile-plank-supported low subgrade has smooth stiffness along the longitudinal subgrade and can effectively control the progressive effects of train speed on dynamic stiffness of the subgrade, which ensures driving safety and comfort. The cycle loading experimental results show that the pile-plank-supported low subgrade has favorable long-term dynamic stability, and its dynamic response is uniform along the longitudinal subgrade.

Suspension Dynamics and Design Optimization of a High Speed Railway Vehicle

Joint Rail ◽  
2004 ◽  
Author(s):  
Kazuhiko Nishimura ◽  
N. C. Perkins ◽  
Weiming Zhang
Keyword(s):  
High Speed ◽  
Design Strategy ◽  
Vehicle Body ◽  
Ride Quality ◽  
Railway Vehicle ◽  
High Speed Railway ◽  
Design Objective ◽  
Lumped Parameter ◽  
Power Spectral ◽  
Suspension Dynamics

The design of suspension systems for high speed railway vehicles involves the simultaneous consideration of those requirements as suspension packaging, ride quality, stability, and cost. A design strategy is presented in this paper that enables an optimal design with respect to these competing requirements. The design strategy consists of four steps including the development of a lumped parameter vehicle model, the determination of vehicle parameters, the formulation of a design objective, and the minimization of the objective to optimize key suspension parameters. The design objective captures vehicle requirements including ride quality, suspension packaging, and wheel/rail holding. Power spectral densities (PSDs) are computed for the vertical vehicle body acceleration, suspension travel and dynamic wheel/rail interaction. The design objective function is calculated based on these PSDs and minimized to yield an optimum. An example suspension design is proposed that improves vehicle ride quality and wheel/rail holding without sacrificing other requirements.

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