Development Of High-speed Railway Research Articles

Research on the Connecting Path Search Algorithm for Air-Rail Integration

With the rapid development of high-speed railway and the changes of the tourists’ requirement, it is imperative to the integrate advantages of aviation and rail. This paper constructs the air-rail integration model based on the current development situation and characteristics of Chinese railways. In allusion to the search problem of connecting path in air-rail integration network, a constrained Yen* algorithm is proposed to solve the problem in this paper. The constrained Yen* algorithm is set up by using the heuristic strategy of A* algorithm and two certain constraints by reducing running time to generate candidate paths. The experimental results show that the search problem of connecting path in air-rail integration network can be obtained fast by the constrained Yen* algorithm. Therefore, constrained Yen* algorithm is more efficient than constrained Yen algorithm in application.

Deformation and failure modes of composite foundation with sub-embankment plain concrete piles

With the development of high-speed railway in China, composite foundation with rigid piles has become a standard solution of meeting the high requirements of stability and post-construction settlement of embankment on soft subgrade. Among several improvement patterns, plain concrete piles have been extensively used to treat soft ground supported embankment. To investigate the deformation and failure modes of unimproved soft ground and soft ground reinforced by sub-embankment plain concrete piles,and to learn the influences of track and vehicle load, the effect of pile spacing, as well as the compression moduli of soil layers and upper load condition on the failure modes, a series of centrifuge model tests were performed. Test results indicate that the displacement of unimproved soft ground under the embankment increases continuously as embankment, track and train loading, and slip circle failure takes place. The deformation law of soft ground reinforced by sub-embankment plain concrete piles depends on pile spacing, compression modulus of the soft ground, and loading conditions. It was also found that plain concrete piles show displacement and failure patterns depending on its location, compression modulus of soft soil around the pile, and loading conditions. Furthermore, the evaluation of improved ground stability as well as the model test procedure is also presented.

Train Detection by Magnetic Field Sensing

The recent boom in the development of high-speed railways has stimulated the need for train detection technology to enhance safety and reliability. In this paper, we propose a new technique of train detection through magnetic field sensing by giant magnetoresistive sensors. This technology was studied by the analysis of magnetic field distribution in the high-speed rail system obtained from modeling and simulation. The results verify the feasibility of our technology for the detection of train presence, speed, length, and number of rolling stocks. It can overcome the limitations of track circuits and provide additional measurement capabilities to the signaling system. This detection system is of low cost and minimal maintenance load as well as compacted construction. Thus, it may serve as a new train detection system to help enhance and promote the safety and reliability of high-speed railways.

A Hybrid Temporal-Spatio Forecasting Approach for Passenger Flow Status in Chinese High-Speed Railway Transport Hub

With the rapid development of high-speed railway in China, high-speed railway transport hub (HRTH) has become the high-density distribution center of passenger flow. In order to accurately detect potential safety hazard hidden in passenger flow, it is necessary to forecast the status of passenger flow. In this paper, we proposed a hybrid temporal-spatio forecasting approach to obtain the passenger flow status in HRTH. The approach combined temporal forecasting based on radial basis function neural network (RBF NN) and spatio forecasting based on spatial correlation degree. Computational experiments on actual passenger flow status from a specific bottleneck position and its correlation points in HRTH showed that the proposed approach is effective to forecast the passenger flow status with high precision.

Semi-Deterministic Path-Loss Modeling for Viaduct and Cutting Scenarios of High-Speed Railway

Semi-deterministic modeling with low data resolution requirement and low computation time is always of interest. By conjunctively utilizing the extended Hata model and the Deygout model, this letter presents a hybrid model for viaduct and cutting scenarios of high-speed railway. The proposed model achieves higher accuracy than empirical and statistical models, but uses totally free sources. It can be easily implemented for the network planning, and therefore, it meets the demand for fast development of high-speed railway.

Protection Schemes for Uniline Zone in Bilateral AT Traction Power Supply System

With the rapid development of the construction of high-speed railway in china, higher levels of power quality and reliability of traction power supply systems are required.The combination of bilateral power supply technology with AT traction power supply technology can better meet the needs of development of high-speed railways, which will require new protection approaches to be proposed. Thus, corresponding protection schemes will be of great significance for the application and promotion of bilateral power supply technology.

A new method for measuring subgrade settlement in high-speed railway by using a linear CCD

With the rapid development of high-speed railway in China, measurements and controls of subgrade settlement have attracted much attention in recent years. A novel method to measure the subgrade settlement is proposed and a device has been developed. The device mainly contains a point light source and a point-position measurement device that uses a linear CCD to detect the position change of the point light’s image. Any position change of the point light source can be measured and the settlement for one point can be obtained remotely. The multi-point settlements can be obtained by using a series of such devices. Some methods such as self-calibration of the magnification, automatic background subtractions have been adopted to enhance the stability, adaptability and accuracy of the measurement system. The device has been used in some China high-speed railway sites and it has the advantages of high accuracy, low-cost and easy installation.

Numerical Study of Smoke Control for Underground Platform in a High-Speed Railway Station

Smoke control for the underground platform of a high-speed railway station was investigated. Nowadays, the development of high-speed railway in China is rapid. In order to economize valuable urban space and to realize the convenient interchange to the subway, some of the high-speed railway station platforms and transfer halls are set underground. It is difficult and uneconomic to achieve static ventilation in the underground platform. Therefore, The mechanical smoke control system is the most feasible and most reliable method to ensure the fire safety of the underground platform. How to protect the evacuation stairs free from the threat of fire-induced smoke is a major concern of smoke control in the underground platform. An underground island platform and underground waiting and transfer halls of an under construct high-speed railway station in south China are reconstructed in this paper. Three smoke control modes based on mechanical ventilation, namely mechanical air makeup, pressurized air supply for stairwell and air curtain, are numerically simulated by Computational Fluid Dynamics (CFD) method. The distribution of smoke, temperature, and CO in the platform and influences of them on evacuation staircases are computed and analyzed. The effect of fire location in smoke spread are explored in our research. This study based on CFD modeling enables the improvement of the design and operation of smoke control and exhaust system for underground high-speed railway station. The results are applicable to practical fire engineering designs for underground high-speed railway station platform.

Study Platform for AC Transmission System of High-Speed Train

Demand for CRH (China Railways High-Speed) trains, both in quantity and types, is increasing because of the rapid development of high-speed railway in China. To support the improvement and development the AC transmission system of these trains, a study platform is proposed in this paper. Target of the platform is supporting the study which contains design, verification, display etc. in detail. Platform framework is described in this paper. And the results of study on transmission system temperature rise and energy-saving operation strategy of high-speed train based on the platform are displayed. Availability of the study platform is verified.

Effect of Eccentric Pounding on Elasto-Plastic Behavior of a Simply Supported Bridge under Transverse Earthquake

An increasing number of bridges have been built in earthquake zones, alonged with rapid development of high-speed railway. Their seismic behaviors attract researchers’ attention now. The steel shear keys as falling-off prevention measures have been used widely in 32m simply-supported box girder bridges on high-speed railways in China. To allow for transverse temperature movement, the shear keys are placed with a slight gap from the girders. However, out-of-phase vibrations between superstructures and substructures result in nonlinear eccentric pounding between bearing base and steel shear keys if the relative displacements exceed their initial gaps. The aim of this paper is to analyze the effect of eccentric pounding on elasto-plastic behavior of a simply-supported concrete box girder bridge under transverse earthquake, and evaluate the seismic performance of falling-off prevention measures. The effect of cushion block on seismic response has been studied. The results of the study indicate that a bridge column occur plastic deformation and suffer residual displacements due to eccentric pounding, and simple analysis in elastic range may result in nonconservative results. The lateral shear keys play a key role in limiting girder displacements. By setting hardwood blocks between steel shear keys and bearing base, the pounding forces can be appropriately reduced, and the lateral seismic performance of bridge can be effectively improved

The Vibration Response Analysis about High-Speed Train’s Braking Wing

With the rapid development of high-speed railway in China, the aerodynamic brake is very likely to be an important emergency braking mode of high-speed train in the future. This paper takes aerodynamic braking wing as the object, and uses the finite element software to divide the meshes, then analyses the model influenced by static stress. After simulating the vibratory frequency response of the model in the flow field, it finds that the largest deformation happens in the middle of the upper edge of the wind wing, when the wind speed gets to 500km/h and the load frequency to 4Hz. Some conclusions of this thesis can provide reference for researching the applying the aerodynamic brake in the high-speed trains and laying the foundation for solving the riding and braking safety problems.

A CoMP soft handover scheme for LTE systems in high speed railway

With the development of high-speed railway and public growing demand on data traffic, people pay much more attention to provide high data rate and high reliable services under high mobility circumstance. Due to the higher data rate and lower system latency, long-term evolution (LTE) has been chosen as the next generation's evolution of railway mobile communication system by the International Union of Railways. However, there are still many problems to be solved in the high mobility applications of LTE, especially the higher handover failure probability, which seriously degrades the reliability of railway communication. This article proposes an optimized handover scheme, in which the coordinated multiple point transmission technology and dual vehicle station coordination mechanism are applied to improve the traditional hard handover performance of LTE. The scheme enables the high speed train to receive signals from both adjacent base stations and obtain diversity gain when it moves through the overlapping areas, so it improves the quality of the received signal and provides reliable communication between train and ground eNodeBs. Numerical analysis and simulation results show that the proposed scheme can decrease the outage probability remarkably during handover and guarantee the reliability of train to ground communication.

Study of Traffic Accessibility in Poyang Lake Economic Zone Oriented by High-Speed Railway

The high-speed railway framework can promote the harmonious development in the unbalanced regions. Based on construction experiences and spatial development of high-speed railway, the spatial effects were analyzed in traffic economic belt, regional balance, spatial organization reconfiguration and urban environment improvement. According to the high-speed rail plan of China, the traffic accessibility of spatial organization in Poyang lake economic zone were discussed in internal traffic accessibility and external traffic accessibility. The study results showed that the hub-and-spoke patterns of the spatial traffic organization reconfiguration in Poyang Lake agglomeration can realize the regional balance oriented by the high-speed railway. The patterns can be also applied to other underdeveloped and unbalanced regions.

Seismic response analyses of high-speed railway bridge round-ended piers using global bridge model

The non-linear failure occur in pier bottom which may cause the collapse or damage of bridge under high-level earthquake, lots of researchers have been paying more and more attention to the seismic behaviour of high-speed railway bridge piers with the development of high-speed railway. The seismic responses of high-speed railway round-ended piers are investigated in this paper. The global finite element model of the multi-span bridge simply supported bridge is set up under earthquake action, the round-ended piers are taken into account as part of whole bridge, by means of finite element software and moment-curvature relationship programme, the seismic responses of bridge piers are calculated under the different earthquake action combination, pier height and vehicle speed. Calculation results show that the seismic responses will increase with increment of speed of vehicles, pier height and seismic intensity, the elastic-plastic deformation will occur at the pier bottom under high-level earthquake action, and some measures such as lateral reinforced steel encryption should be taken into account to ensure safety.

Design and reliability, availability, maintainability, and safety analysis of a high availability quadruple vital computer system

With the development of high-speed railways in China, more than 2000 high-speed trains will be put into use. Safety and efficiency of railway transportation is increasingly important. We have designed a high availability quadruple vital computer (HAQVC) system based on the analysis of the architecture of the traditional double 2-out-of-2 system and 2-out-of-3 system. The HAQVC system is a system with high availability and safety, with prominent characteristics such as fire-new internal architecture, high efficiency, reliable data interaction mechanism, and operation state change mechanism. The hardware of the vital CPU is based on ARM7 with the real-time embedded safe operation system (ES-OS). The Markov modeling method is designed to evaluate the reliability, availability, maintainability, and safety (RAMS) of the system. In this paper, we demonstrate that the HAQVC system is more reliable than the all voting triple modular redundancy (AVTMR) system and double 2-out-of-2 system. Thus, the design can be used for a specific application system, such as an airplane or high-speed railway system.

Operation and Organization Management of High-speed Railway in Japan

Under the background of the rapid development of high-speed railway in China, the paper analyzes the world's first operational high-speed railway—Japan Shinkansen to get a clear solution to the problems of the organization and management operations of high-speed railway. On the basis of actual operating data, the means and measures in organization and operational management of Japan Shinkansen are evaluated by horizontal and vertical comparison. And then, the paper makes the judgment to the related issues of the development of China's high-speed railway. Some conclusions are made, such as the development speed should not be too fast. The high-speed railway should be operated at the same railway station with the traditional railway with multi-parking program train. The competitive advantage within 600 km should be extensively explored. And it is essential to conduct scientific fare adjustment mechanism and put the energy consumption and emissions in the first place. The research provides reference for high-speed railway sustained and healthy development in China.

Research on Seismic Response and Damping Effect for High-Speed Railway Seismic Isolated Bridge

With the development of high-speed railway in recent years, lots of researchers have been paying more and more attention to the seismic isolation of high-speed railway bridge. The equivalent linear model of hysteretic characteristics of lead rubber bearings (LRB) is presented, the computational method and the varying range of dynamic parameters effecting hysteretic characteristics of LRB are established. The finite model of a high-speed railway bridge including simulating of LRB is set up by ANSYS software. The seismic responses and seismic isolation ratio of high-speed isolated bridge installed LRB are calculated, and isolation effect are compared with those fabricated the common bearings; the factors which influence seismic isolation are analyzed. The calculation results show that the bending moment and shear force of pier bottom of and displacement of grider decrease effectively for that bridge with LRB, the LRB has excellent performance on seismic isolation and energy dissipation.

Travel Mode Chioce of High-speed Railway Passenger Modeling with Support Vector Machines

High-speed railway is a very important part of transportation industry in China, and travel choice has key effect on the development of high-speed railway. Therefore,research on travel behavior of passengers and prediction their travel choice, will offer valuable suggestion for high-speed railway running. In this paper, support vector machine (SVM) is the main method being used to predict. Support vector machine is based on the structural risk minimization principle, and it improves the generalization ability of learning machine to the maximum extent. When solving the limited-sample and nonlinear problems, support vector machine has advantages in predicting. In this research, we get six most important factors, which affect travel choice by the means of questionnaire survey, then use libsvm tool to build prediction model and optimize the train parameters of support vector machine. Finally the prediction accuracy is as high as 91.44%, which shows that support vector machine is good at predicting.

Composite Foundation on Bearing Characteristics and Simulation Analysis CFG Pile for the High Speed Railway

With the rapid development of high-speed railway in soft foundation, foundation treatment technology has become mature, the most outstanding is CFG pile composite foundation technique. CFG pile composite foundation is made of cement fly ash gravel pile(CFG pile), pile of soil and sandstone , between sand and gravel several problems such as the medium material composition together constitute layer. It has high bearing of capacity, convenient, low costing, strong adaptability and quality control easier.So it is widely applied and promoted. Under static and dynamic loads, the relations of the high-speed railway CFG pile composite foundation is very complex. In order to further understand the intensity of pile-net structure subgrade stability and deformation, pile , requirements of the high-speed railway roadbed ,it needs to do pile-net structure parameter sensitivity analysis. According to high-speed railway CFG pile composite foundation , the numerical analysis can well solve the coupling effect of piles and soil. So, this paper adopts FLAC3D finite difference software is simulated and analyzed.

Numerical Seismic Analysis of Simply-Supported Girder Railway Bridge under High-Speed Train Load

Along with rapid development of high-speed railway in many countries, recently research on seismic response of high-speed railway bridge under train load has raised much concern among researchers. The whole bridge finite element model is establish to analysis the seismic responses of simply-supported girder railway bridge subjected to high-speed train in this paper, ICE series high speed vehicle is employed as train live load, the vehicle is simulated by moving spring-mass system, The track irregularities can be obtained by Simpack software, the birdge incluing superstructure and substructure is three-dimensional space beam element, the bottom of piers is proposed consolidated. elastic seismic responses of bridge system and elastic-plastic deformation of piers considering different train speeds are calculated. The calculation results indicate that, seismic responses of bridge system are increase with the increase of train speed and earthquake intensity, and the bottom of piers will step into elastic-plasticity stage under high-level earthquake, the plastic hinges occurred within 1.4 meters of bottom of pier. The numerical results can provide some references for design of high-speed railway bridge.