Study of the characteristics of ballast bed resistance for different temperature and humidity conditions

Proceedings of the Institution of Mechanical Engineers, Part F:

2022

The planned 400 km/h high-speed train capable of cross-border intermodal transportation will inevitably cause a greater return-current and bring more challenges to signaling infrastructure and integrated grounding while achieving stronger traction. Based on the existing AC autotransformer power supply mode, this paper proposes a discrete modeling and calculation method of the traction return-current network concerning impedance equivalent, realizing the simulation and quantitative analysis of the return-current distribution of multiple current-carrying conductors in the block section and station yard under the double-track condition. Then, the dynamic distribution is analyzed comprehensively considering traction power supply, signaling, and integrated grounding systems. Also, the method is verified with field test data. Finally, the simulation of the return-current proportion of multiple conductors is carried out under the dynamic operating conditions of high speed, and the distribution characteristics are compared and analyzed under different ballast resistances. In the most unfavorable case, the maximum return-current in the rails, grounding wire, and protective wire can reach 1046 A, 180 A, and 126 A, respectively. This work helps evaluate the electromagnetic compatibility between signaling and strong currents in engineering practice, further optimize the capacity configuration of equipment along the railway lines, and improve the signaling immunity design.

Section: Distribution Proportion Of Return-currentmentioning

confidence: 99%

Discrete modeling and calculation of traction return-current network for 400 km/h high-speed railway

Yang

Proceedings of the Institution of Mechanical Engineers, Part F:

2022

“…38 And the setting of the ambient temperature in the chamber was maintained for 36 h before relevant tests were performed in order to ensure that the internal temperature of the ballast met the requirements. 31 Influence of the temperature and the moisture level on the AOR of the ballast Five groups of tests were conducted on the AOR of the ballast for each condition. The test results are shown in Table 1.…”

Section: Laboratory Tests Of Ballast Aormentioning

confidence: 99%

Section: Laboratory Experiments Of the Ballast Aormentioning

confidence: 99%

“…And the previous research has found that low temperature and moisture have had a significant effect on the resistance performance of ballast bed. 31 This study explored the performances (of course, the most important performances were friction and interlocking) of ballast at different temperatures and moistures using the relatively simple method of AOR. Meanwhile, researchers who use EDEM to study the railway ballast are faced with the problem that the parameters commonly used in the physical tests or the other software cannot be directly used in EDEM.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical and experimental investigations of the effect of temperature and moisture on the repose angle of railway ballast

Wang

Proceedings of the Institution of Mechanical Engineers, Part F:

et al. 2021

Self Cite

The angle of repose (AOR) is one of the key parameters used to comprehensively characterize the basic mechanical properties and stacking properties of granular materials. In this research, the influence of temperature and moisture on the stacking performance of railway ballast was studied through tests of the AOR. Additionally, the parameters of the discrete element method (DEM) for ballast beds with various temperatures and moisture levels were calibrated and combined with the response surface method. Then, the AORs of the ballast in different environments were simulated with the DEM, and the micromechanical properties of the ballast in dry, wet, low-temperature, and frozen environments were compared. The results showed that the AOR of the ballast in a frozen environment was smaller than that in a dry environment at the same low temperature (the difference could reach 8.48° at −30°C). The AOR of the ballast increased with the decrease of the temperature in a dry environment (18.44% increase between 20°C and −30°C). The AOR of the ballast decreased with the decrease of the temperature in a wet (frozen) environment (22.86% decrease between 20°C and −30°C). In addition, the validity tests of the AOR simulations of ballast proved that the obtained parameters could be used in the DEM models of ballast for the corresponding temperature and moisture. At the same time, it was found that with the change of temperature and moisture, the force chain network of the ballast would also change.

Proceedings of the 31st European Safety and Reliability Conference (ESREL 2021)

“…This phenomenon can negatively affect the behavior of ballasted structures. Liu et al (2020a) performed a full-scale test of a ballasted railway track inside a test chamber in which the temperature and humidity was altered to find how changes in these parameters affect the ballast bed resistance. The authors concluded that the ballast bed resistance was lower in a dry, cold environment as compared to normal conditions.…”

Section: Climate Change Impact On Ballasted Railway Structuresmentioning

confidence: 99%

Pressure Distribution Patterns Between the Ballast and the Concrete Slab in Railway Trough Bridges

Silvia¹,

Nova²,

Gustafsson³

et al. 2021

In Sweden, a substantial amount of railway bridges is approaching their intended lifespans and are planned to be replaced. However, it is not sustainable neither from a financial nor an environmental perspective to replace these bridges if they are still sound and safe. Thus, an evaluation of their actual capacity is required with the aim of extending their lifespans. A way to obtain a more accurate capacity is to determine the loads that are acting on them. Available literature points out the lack of experimental investigations on sleeper-ballast contact pressure, as well as on the stress distribution along and across the ballast. Consequently, railway bridge design has been based on traditional rather than rational assumptions, which can be quite conservative. In this paper, a review of models is carried out for evaluating stress patterns on the surface of the slab on ballasted concrete bridges. Then, a simplified finite element model of a concrete trough bridge, a common type of structure in Sweden, is used in a parametric analysis aimed to understand how the identified pressure distribution patterns affect the performance of this type of structure. Finally, with the purpose of studying how some parameters influence the bridge safety, a probabilistic reliability analysis is used. The reliability index beta ( ) is obtained using the polynomial response surface method and its value is compared for different boundary condition scenarios. Also, the sensitivity factors for the considered random variables are compared and analyzed. Results show that the assumption of support condition and pressure pattern has a significant impact on the capacity, failure mode and probability of failure of this type of structure.