scholarly journals Study on the Calculation Method of the Diffusion Range of Grouting Slurry for a High-speed Railway Ballastless Track Subgrade

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Changwei Yang ◽  
Jinhao Guo ◽  
Shaowei Wei ◽  
Liang Zhang ◽  
Sifeng Li ◽  
...  
Keyword(s):  
High Speed ◽  
Theoretical Study ◽  
Early Stage ◽  
Soil Mass ◽  
High Speed Railway ◽  
Grouting Pressure ◽  
Diffusion Curve ◽  
Practical Engineering ◽  
Simulation Results ◽  
Diffusion Form

Grouting engineering is the most convenient and quick way to deal with postconstruction settlement. Based on the investigation of the Beijing Shenyang high-speed railway in the early stage, the microdestructive force of grout on the soil mass in the process of grouting with the method of fluid solid coupling theory was analyzed. The numerical simulation results show that, in the grouting process, the greater the grouting pressure, the wider the diffusion range of the slurry and the greater the damage to the microscopic contact force of the slurry to the soil; in addition, when the grouting pressure is below 0.15 MPa, the diffusion form of the slurry in the soil is osmotic grouting; when the pressure is about 0.3 MPa, the diffusion form of the slurry in the soil is compacted grouting; on the basis of the simulation results, a deeper research is carried out, and the calculation formula of the slurry diffusion curve is obtained. It fills in the blank of the theoretical study of the slurry diffusion curve. In this paper, the diffusion formula of grouting slurry can be used in the theoretical study of clay grouting, and it can be used as a reference for practical engineering.

STRATEGIC ENVIRONMENT ASSESSMENT AND BIOLOGICAL DIVERSITY CONSERVATION IN THE KOREAN HIGH-SPEED RAILWAY PROJECT

2005 ◽  
Vol 07 (02) ◽  
pp. 287-298 ◽  
Author(s):  
SANG DON LEE
Keyword(s):  
Biodiversity Conservation ◽  
High Speed ◽  
Biological Diversity ◽  
Developmental Process ◽  
Early Stage ◽  
Amphibian Species ◽  
High Speed Railway ◽  
Ecosystem Conservation ◽  
Environment Assessment ◽  
Development Site

Biological diversity (biodiversity) is an essential issue in conservation and environmental impact assessment (EIA). Though Korea is relatively small, the country harbours over 29,800 species, making biodiversity and ecosystem conservation a central issue when an EIA is undertaken during development site selection. Indeed, an unfavourable biodiversity evaluation can halt a proposed or in-progress development, creating a societal conflict between conservationists and developers. To solve this, the Strategic Environment Assessment (SEA) legislation was created in Korea to provide a systematic instrument for improving decision-making through early-stage environmental assessment. The SEA legislation was recently passed by the President's cabinet and is poised for implementation during 2005. Adoption of the SEA will facilitate better assessments of biodiversity during the early stages of the developmental process, preventing late-stage interruptions such as those seen in the Korean High-speed Railway Project (KHRP), which was recently halted due to poor biodiversity conservation around the development site. The original EIA of the KHRP did not appropriately address the biodiversity issues because most of the developmental plan had been set in place prior to evaluation of biodiversity in the affected areas. The KHRP caused leakage of mountain groundwater such that high elevation wetlands marked as ecosystem conservation areas by the Ministry of Environment became dry and lost their endemic amphibian species. Upon learning this, several national NGOs filed court cases on behalf of the Korean clawed salamander (Onachodaytylus fisheri), halting the project for some time. Thus, the lack of biodiversity consideration at the earliest stages of the KHRP created a social conflict. This paper examines how the implementation of an SEA during the KHRP would have minimised the social conflicts between biodiversity conservation and developmental processes.

scholarly journals Dynamic Analysis of a High-Speed Railway Train With the Defective Axle Bearing

2020 ◽  
Vol 25 (4) ◽  
pp. 525-531
Author(s):  
Jing Liu ◽  
Shangkun Du
Keyword(s):  
Dynamic Analysis ◽  
High Speed ◽  
Time Dependent ◽  
Force Model ◽  
High Speed Railway ◽  
The Road ◽  
Reasonable Approach ◽  
Simulation Results ◽  
Train System ◽  
Track Irregularities

Axle bearings (AXBs) are critical parts for high-speed railway trains (HSTs). Local faults in the AXBs have great influences on the operational dynamics of HSTs. Although some previous works formulated the local faults in single AXB, the vibrations of the whole train system with the defective AXB cannot be described. To overcome this problem, this study conducts a dynamic model for a HST considering a local fault in one AXB. The previous single AXB model cannot formulate the studied case. The impacts caused by the fault in the AXB is defined as a time-dependent force model considering a half-sine type. The road spectrum excitations from the roadbed and rail are formulated by a track irregularities model. The effects of the train speeds and fault sizes on the HST dynamics are introduced. The simulation results from the proposed and previous works are contrasted to show the model validation. The results show that the faults in the AXB will greatly affect the HST dynamics. It depicts that this study can afford a more reasonable approach for understanding the dynamics of HSTs considering the defective AXBs compared to the reported single AXB model.

Railway faults spreading model based on dynamics of complex network

2015 ◽  
Vol 29 (06) ◽  
pp. 1550038 ◽  
Author(s):  
Jin Zhou ◽  
Weixiang Xu ◽  
Xin Guo ◽  
Xin Ma
Keyword(s):  
Dynamic Process ◽  
High Speed ◽  
Transmission Rate ◽  
Sir Model ◽  
Directed Network ◽  
High Speed Railway ◽  
Spreading Model ◽  
Accident Causation ◽  
Simulation Results ◽  
Initial Recovery

In this paper, we propose a railway faults spreading model which improved the SIR model and made it suitable for analyzing the dynamic process of faults spreading. To apply our model into a real network, the accident causation network of "7.23" China Yongwen high-speed railway accident is employed. This network is improved into a directed network, which more clearly reflects the causation relationships among the accident factors and provides help for our studies. Simulation results quantitatively show that the influence of failures can be diminished via choosing the appropriate initial recovery factors, reducing the time of the failure detected, decreasing the transmission rate of faults and increasing the propagating rate of corrected information. The model is useful to simulate the railway faults spreading and quantitatively analyze the influence of failures.

Beamforming with Kerdock Codes in LTE System for High-Speed Railway

2014 ◽  
Vol 989-994 ◽  
pp. 3556-3560
Author(s):  
Zhi Hua Yang ◽  
Lei Jun Wang ◽  
Ze Kai Fang
Keyword(s):  
Bit Error Rate ◽  
Communication System ◽  
System Performance ◽  
High Speed ◽  
High Speed Railway ◽  
Kerdock Codes ◽  
Simulation Results ◽  
Complex Multiplications ◽  
Beamforming Technique ◽  
Ber Performance

Beamforming technique based the reciprocity of LTE communication system for high-speed railway is a practical way to improve the system performance in this paper. Kerdock codes, which facilitate efficient codebook and codeword search, are implemented in the LTE system for high-speed railway as the beamforming precoding codebook. The analysis of complexity and simulation results about the communication system of the beamforming with Kerdock codes (KBF) show that the proposed KBF can eliminate complex multiplications and improve the Bit Error Rate (BER) performance at large SNR compared with the existing beamfoming communication system for high-speed railway.

scholarly journals Negative External Cost Computing Model for Noise of China’s High-speed Railway and its Verification and Trend Analysis

2021 ◽  
Vol 261 ◽  
pp. 03029
Author(s):  
Xiaomei Xuan
Keyword(s):  
Noise Reduction ◽  
High Speed ◽  
Early Stage ◽  
Rapid Development ◽  
Density Ratio ◽  
External Noise ◽  
Future Trend ◽  
Cost Calculation ◽  
External Cost ◽  
High Speed Railway

The purpose of this paper is to calculate the external noise cost of China’s high-speed railway and forecast its future trend. Firstly, the unit value transfer method after correction is selected as a method of calculation. Secondly, the noise cost calculation model of China’s high-speed railway is established by introducing the correction factors such as GDP-PPP, population density ratio and CPI ratio. At last, the external noise cost since the opening of high-speed railway is calculated. The model validation results show that although the average external noise cost of high-speed railway increases year by year, it does not increase significantly. This is not only related to economic growth and improvement of noise reduction technology, but also related to the increase of investment in noise reduction facilities in the early stage. Compared with it, the total external cost of high-speed railway noise increases obviously, which is positively related to the rapid development of high-speed railway. With the increase of high-speed railway mileage and passenger turnover, the total noise cost increases significantly. It can be predicted that with the implementation of high-speed railway planning in the future, the negative external cost of noise will continue to increase.

scholarly journals A Supercapacitor-Based Method to Mitigate Overvoltage and Recycle the Energy of Pantograph Arcing in the High Speed Railway

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1214
Author(s):  
Cuidong Xu ◽  
Zhu Chen ◽  
Ka Cheng ◽  
Xiaolin Wang ◽  
Ho Ho
Keyword(s):  
Service Life ◽  
High Speed ◽  
Electronic System ◽  
Electrical Equipment ◽  
Power Electronic ◽  
High Speed Railway ◽  
Electromagnetic Transient ◽  
Bidirectional Converters ◽  
Devices And Instruments ◽  
Simulation Results

The pantograph arcing phenomenon may shorten the service life of a pantograph and even destroy onboard devices and instruments, due to the irregular motions of the train and the intermittent line–pantograph disconnection. This paper points out that abrupt inductive energy from the magnetizing inductance of the traction transformer can lead to an electromagnetic transient process with unexpected overvoltage across it. Further, a supercapacitor-based power electronic system is proposed, which can not only redirect the inductive energy to the supercapacitor pack through bidirectional converters but also mitigate the overvoltage across the main electrical equipment when pantograph arcing occurs. Simulation results show the overvoltage could be reduced and the energy stored in the supercapacitor which could also be used to provide energy for sensors or other devices.

Optimization Analysis of Height and Distance for Shelter Wind Wall of High Speed Railway

2012 ◽  
Vol 588-589 ◽  
pp. 1794-1800 ◽  
Author(s):  
Kun Ye ◽  
Ren Xian Li
Keyword(s):  
Numerical Analysis ◽  
High Speed ◽  
Three Dimensional ◽  
Aerodynamic Forces ◽  
Optimization Analysis ◽  
High Speed Railway ◽  
Rolling Moment ◽  
Side Force ◽  
Wind Speeds ◽  
Simulation Results

Shelter wind wall is one of the most effective devices to reduce crosswind loads acting on trains. The height of the wall and distance between the wall and the center of railway are important factors for design and construction of wind wall. Since the wall design is related to many factors, such as train speeds, transverse wind speeds, types of the wall and so on, up to now, there are still different judgment methods in the optimal height and distance of the wall to get minimum aerodynamic forces on the train. Based on numerical analysis methods of three-dimensional viscous compressible aerodynamics equations, aerodynamic side forces and rolling moments acting on the train are analyzed. With 275 calculation models, include the straight and different radius curve railway with different heights and distances of shelter wind wall, the aerodynamic side forces and rolling moments are calculated. Simulation results show that the optimal height and distance of the wall are not the same during in straight and curve railway. And the direction of aerodynamic side force and rolling moment acting on the head and rear train may be different. The change trends of transverse forces (moments) with the height and distance of the wall are also different.

Wheel/Rail Dynamics Simulation for Optimising Minimum Grade Lengths to High-Speed Railways

2007 ◽  
Author(s):  
Zengjie Liu ◽  
Lan Wang
Keyword(s):  
High Speed ◽  
Dynamics Simulation ◽  
Minimum Length ◽  
Maximum Speed ◽  
Simulation Studies ◽  
High Speed Railway ◽  
Vertical Transition ◽  
Simulation Results ◽  
Curve Radius ◽  
Transition Curves

Based on the principle of no car vibrations interference when trains pass grade section from the end of front vertical curve to the start of latter vertical curve, using railway wheel/rail simulation NUCARS™ software, some dynamics simulation studies for minimum grade lengths on high speed railway lines were made. The dynamics simulation results show that, the minimum tangent lengths between vertical transition curves should be more than 0.43V in meters (V is speed of train, km/h). So the minimum length is 800 meters when the vertical curve radius is 25000 meters, and 900 meters when radius is 30000 meters for the Chinese Dedicated Passenger Railway lines (PDLs) on which maximum speed is 350 km/h and ruling gradient is 12‰.

Ground Movements in Shield Tunneling and Impacts on Railway Culvert

2014 ◽  
Vol 680 ◽  
pp. 190-193
Author(s):  
Yu Zhuo Jia ◽  
Rui Li
Keyword(s):  
High Speed ◽  
Soil Layer ◽  
Element Model ◽  
Soil Mass ◽  
Shield Tunnel ◽  
Shield Tunneling ◽  
Tunnel Excavation ◽  
High Speed Railway ◽  
Railway Operation ◽  
Box Culvert

The excavation of the tunnel will inevitably cause the displacement of soil layer, and then further threatens the safety of high-speed railway operation. Under the engineering background of high-speed rail’s box culvert, using the technique of MIDAS/GTS, the establishment is based on 3 d finite element model of tunnel, soil mass and box culvert, to analyze the effects of box culvert settlement that led by shield tunnel excavation. The research indicates that tunnel excavation causes settlement of box culvert to some large extents, the soil mass should be reinforced to ensure the safety of the high-speed railway operations during the shield construction.

scholarly journals Exploring Boarding Strategies for High-Speed Railway

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Tie-Qiao Tang ◽  
Yi-Xiao Shao ◽  
Liang Chen ◽  
Hai-Jun Huang ◽  
Ziqi Song
Keyword(s):  
Cellular Automaton ◽  
High Speed ◽  
Pedestrian Flow ◽  
High Speed Railway ◽  
Passenger Transportation ◽  
Ca Model ◽  
Simulation Results ◽  
Increasing Demand ◽  
Positive Impacts

In light of the increasing demand for passenger transportation on high-speed railway (HSR), the pedestrian flow at HSR stations has become quite crowded in many countries, which has attracted researchers to study the HSR boarding behavior. In this paper, we propose three boarding strategies based on the features of the boarding behavior at an origin HSR station; we then use a cellular automaton (CA) model to study the impacts of boarding strategies on each passenger’s motion during the boarding process at HSR station. The simulation results indicate that some of the three strategies can optimize some passengers’ boarding time and relieve the congestion degree, and the positive impacts on the boarding process are the most prominent when the three strategies are used simultaneously. The results can help administrators to effectively organize the boarding process at the origin HSR station.

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