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.

scholarly journals Mechanical Performance of a Ballastless Track System for the Railway Bridges of High-Speed Lines: Experimental and Numerical Study under Thermal Loading

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2876
Author(s):  
Yingying Zhang ◽  
Lingyu Zhou ◽  
Akim D. Mahunon ◽  
Guangchao Zhang ◽  
Xiusheng Peng ◽  
...  
Keyword(s):  
High Speed ◽  
Thermal Loading ◽  
Mechanical Performance ◽  
Track Structure ◽  
Box Girder ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Track System ◽  
Girder Bridge ◽  
Track Slab

The mechanical performance of China Railway Track System type II (CRTS II) ballastless track suitable for High-Speed Railway (HSR) bridges is investigated in this project by testing a one-quarter-scaled three-span specimen under thermal loading. Stress analysis was performed both experimentally and numerically, via finite-element modeling in the latter case. The results showed that strains in the track slab, in the cement-emulsified asphalt (CA) mortar and in the track bed, increased nonlinearly with the temperature increase. In the longitudinal direction, the zero-displacement section between the track slab and the track bed was close to the 1/8L section of the beam, while the zero-displacement section between the track slab and the box girder bridge was close to the 3/8L section. The maximum values of the relative vertical displacement between the track bed and the bridge structure occurred in the section at three-quarters of the span. Numerical analysis showed that the lower the temperature, the larger the tensile stresses occurring in the different layers of the track structure, whereas the higher the temperature, the higher the relative displacement between the track system and the box girder bridge. Consequently, quantifying the stresses in the various components of the track structure resulting from sudden temperature drops and evaluating the relative displacements between the rails and the track bed resulting from high-temperature are helpful in the design of ballastless track structures for high-speed railway lines.

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.

scholarly journals Experimental and Numerical Investigation on Repairing Effect of Polymer Grouting for Settlement of High-Speed Railway Unballasted Track

2019 ◽  
Vol 9 (21) ◽  
pp. 4496 ◽  
Author(s):  
Hongyuan Fang ◽  
Yingjie Su ◽  
Xueming Du ◽  
Fuming Wang ◽  
Bin Li
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Polymer Materials ◽  
Railway Track ◽  
Fe Model ◽  
Cement Slurry ◽  
High Speed Railway ◽  
Application Range ◽  
Ballastless Track ◽  
Track Slab

Uneven settlement of high-speed railway subgrade leads to the irregularity of high-speed railway line, which seriously affects high-speed train operation. The skylight point of high-speed railway operation is short and the maintenance time is limited. Therefore, how to quickly lift and repair the ballastless track slab in the subsidence section is an urgent problem to be solved in the maintenance of high-speed railways. The two-component non-aqueous reactive polymer material has the advantages of strong expansive force, fast reaction speed, and wide application range, which is extremely suitable for the repair of high-speed railway track slab subsidence and lifting. In this study, the expansion force characteristics of different density polymer materials and the stress-deformation curves at corresponding density are tested in laboratory to propose the mechanical parameters of polymer. Then, a three-dimensional finite element (FE) model of high-speed railway train ballastless-track subgrade is established based on ABAQUS. The mechanical characteristics of CRTS III ballastless track under different repair materials, different elevation, and different density of polymer grouting materials are analyzed. The results show that, under the dynamic load of the train, the stress value of polymer repairing material is less than that of cement slurry, presenting a compressive stress state, which is similar to that of the complete subgrade surface. In addition, within a certain thickness range, increasing the thickness of polymer is beneficial to reducing the difference of stress variation between polymer filling layer and complete pavement. Once beyond this range, the thickness of polymer has little effect on the force variation.

Analytical study on high-speed railway track deformation under long-term bridge deformations and interlayer degradation

Structures ◽  
2021 ◽  
Vol 29 ◽  
pp. 1005-1015
Author(s):  
Hongye Gou ◽  
Rui Xie ◽  
Chang Liu ◽  
Yi Bao ◽  
Qianhui Pu
Keyword(s):  
High Speed ◽  
Analytical Study ◽  
Railway Track ◽  
High Speed Railway ◽  
Track Deformation

Advanced Full-Scale Laboratory Dynamic Load Testing of a Ballasted High-Speed Railway Track

2021 ◽  
pp. 100559
Author(s):  
Bin Feng ◽  
Yuamar Imarrazan Basarah ◽  
Qiusheng Gu ◽  
Xiang Duan ◽  
Xuecheng Bian ◽  
...  
Keyword(s):  
Dynamic Load ◽  
High Speed ◽  
Full Scale ◽  
Railway Track ◽  
Load Testing ◽  
High Speed Railway

scholarly journals The Design and Implementation of an Inertial GNSS Odometer Integrated Navigation System Based on a Federated Kalman Filter for High-Speed Railway Track Inspection

2021 ◽  
Vol 11 (11) ◽  
pp. 5244
Author(s):  
Xinchun Zhang ◽  
Ximin Cui ◽  
Bo Huang
Keyword(s):  
Kalman Filter ◽  
Navigation System ◽  
High Speed ◽  
Measurement Accuracy ◽  
Railway Track ◽  
Filter Method ◽  
Integrated Navigation ◽  
High Speed Railway ◽  
Track Geometry ◽  
Integrated Navigation System

The detection of track geometry parameters is essential for the safety of high-speed railway operation. To improve the accuracy and efficiency of the state detector of track geometry parameters, in this study we propose an inertial GNSS odometer integrated navigation system based on the federated Kalman, and a corresponding inertial track measurement system was also developed. This paper systematically introduces the construction process for the Kalman filter and data smoothing algorithm based on forward filtering and reverse smoothing. The engineering results show that the measurement accuracy of the track geometry parameters was better than 0.2 mm, and the detection speed was about 3 km/h. Thus, compared with the traditional Kalman filter method, the proposed design improved the measurement accuracy and met the requirements for the detection of geometric parameters of high-speed railway tracks.

scholarly journals Random-Forest Machine Learning Approach for High-Speed Railway Track Slab Deformation Identification Using Track-Side Vibration Monitoring

2021 ◽  
Vol 11 (11) ◽  
pp. 4756
Author(s):  
Gaoran Guo ◽  
Xuhao Cui ◽  
Bowen Du
Keyword(s):  
Random Forest ◽  
High Speed ◽  
Recognition Rate ◽  
Operation Time ◽  
Deformation Monitoring ◽  
Vibration Monitoring ◽  
Railway Track ◽  
Ballastless Track ◽  
Train Operation ◽  
Track Slab

High-speed railways (HSRs) are established all over the world owing to their advantages of high speed, ride comfort, and low vibration and noise. A ballastless track slab is a crucial part of the HSR, and its working condition directly affects the safe operation of the train. With increasing train operation time, track slabs suffer from various defects such as track slab warping and arching as well as interlayer disengagement defect. These defects will eventually lead to the deformation of track slabs and thus jeopardize safe train operation. Therefore, it is important to monitor the condition of ballastless track slabs and identify their defects. This paper proposes a method for monitoring track slab deformation using fiber optic sensing technology and an intelligent method for identifying track slab deformation using the random-forest model. The results show that track-side monitoring can effectively capture the vibration signals caused by train vibration, track slab deformation, noise, and environmental vibration. The proposed intelligent algorithm can identify track slab deformation effectively, and the recognition rate can reach 96.09%. This paper provides new methods for track slab deformation monitoring and intelligent identification.

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