交通运输工程学报

Controlling method of segregation for coarse asphalt mixture

PENG Yu-hua, GUO Da-jin, LIU Hui-xing, YUAN Bao-sheng

Abstract: The segregation characteristics of coarse asphalt mixture were studied, AC-25C was taken as research object, the controlling principle of segregation was analyzed from the aspects of aggregate selection, material transfer, the operating parameters of paver's distribution room and paving pattern, and a controlling method of segregation was proposed.Study result indicates that for AC-25C asphalt mixture, some qualified aggregates from the specifications of S8, S9, S12, S14(S15) and S16 should be chosen.Contrasted with the conventional construction technology, the transverse temperature variable coefficient's extreme value of paving working face decreases from 4.39% to 1.06%, the mass pass rate variable coefficient's extreme value of aggregate passing every sieve size at the different positions of pavement transect decreases from 14.65% to 7.59%, the transverse density variable coefficient's extreme value of surface course reduces from 3.23% to 1.14%, the extreme value of texture transverse depth decreases from 28.14% to 13.79%, and the transverse permeability coefficient's extreme value of pavement reduces from 89.45% to 54.54%.In order to reduce the occurrence of segregation, when distribution room's thread pitch and rotate speed are fixed, the distance between material and axis should be no less 0.75 times of thread pitch.When distribution room's rotate speed and the distance between material and axis are fixed, distribution room's thread pitch should be about 1.3 times of the distance between material and axis.Narrow-size paving is an important way of maintaining uniform pavement.More>

2011, 11(2): 1-7. doi: 10.19818/j.cnki.1671-1637.2011.02.001

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Mechanical properties of ultra-high performance steel fiber reinforced concrete

YANG Song-lin, DIAO Bo

Abstract: Ultra-high performance fiber reinforced concretes (UHPFRC) with compressive strength over 100 MPa were confected by using steel fibers, such as kink end type, flat end type and wavy type. Doped fiber volume ratios were 1.0%, 2.0%, 2.5% and 3.0% respectively. The influences of steel fiber shapes and doped volume ratios on the fluidity, compressive strength, flexural strength, fracture energy and bending toughness of UHPFRC were researched through cube compressive tests and beam flexural tests. Experiment result shows that when doped fiber volume ratios are from 1.0% to 2.5%, UHPFRC with flat end steel fiber has the best flexural strength, fracture energy and bending toughness. When doped fiber volume ratio is 3.0%, UHPFRC with kink end type steel fiber has the best flexural strength, fracture energy and bending thoughness. When doped fiber volume ratio is 2.0%, UHPFRC with flat end type steel fiber has the best construction performance and mechanical performances. When doped fiber volume ratios are from 1.0% to 3.0%, the compressive strength of UHPFRC with wavy type steel fiber is highest than the, but its flexural strength and fracture energy are lowest.More>

2011, 11(2): 8-13. doi: 10.19818/j.cnki.1671-1637.2011.02.002

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Free rolling model of stone on expressway slope

XU Shi-qiang, ZHE Xue-sen, WANG Si-zhang

Abstract: In order to control rolling stone damage on expressway slope, a free rolling model of stone was built. The horizontal moving distance of stone was calculated while reaching the ground. Based on the energy conservation law, the impact energy of rolling stone to guardrail was deduced, and the reasonable way of protection was defined according to the energy. Computation result shows that the horizontal distance (2.156 m) is less than the distance between impact point and road curb (2.820 m), the impact energy is 132 kJ, so passive protecting mesh named AXI-015 (its protecting level is 150 kJ) can provide effective protection, and the model is feasible.More>

2011, 11(2): 14-17. doi: 10.19818/j.cnki.1671-1637.2011.02.003

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Damage identification of cable-stayed bridge based on wavelet packet and random-fuzzy statistic of frequency response function

ZHOU Kui, LI Shen-zhen, SONG Zi-shou, LI Hu-sheng

Abstract: In view of the defects of single-location damage identifying method, the multi-location damage identifying index of cable-stayed bridge in combination with wavelet packet energy spectrum and frequency response function (FRF) was proposed. The random-fuzzy mean was processed with the FRFs of undamaged and damaged structures. Wavelet packet energy spectrum was analyzed with the processed FRFs as wavelet base functions, and the value of accumulated energy variation was extracted to recognize damages. The experiment of a single tower cable-stayed bridge model and the numerical simulations of continuous and simple-supported beams were carried out. Analysis result shows that 1 or 2-loacation damage of bridge model can be identified and located. With the increasing of damage severity, the initial damage index increases linearly, and it will change gently or dramatically when the damage severity approaches 40%-50% or exceeds 50% respectively. The damage identifying result of hammering excitation is better than that of environmental excitation, and the value of hammering exciting load has no effect on identifying precision.More>

2011, 11(2): 18-23. doi: 10.19818/j.cnki.1671-1637.2011.02.004

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Longitudinal creep force properties of wheel and rail under short-pitch corrugation state

REN Li-hui, XIE Gang, WU Zhi-min, SUN Ji-wu, QI Hui

Abstract: Shallowness factor and wavelength ratio were induced to group sinusoidal short-pitch corrugations with simple harmonic waveforms and to analyze the properties of longitudinal wheel/rail creep forces for unsteady state rolling contact, the longitudinal creep forces due to sinusoidal short-pitch corrugations were calculated by Kalker 3D rolling contact theory, and the calculation result was compared with the calculation result from steady rolling contact theory. The system identification method of frequency response was used to fit the fluctuating part of unsteady longitudinal creep force. The relationship of fluctuating parts for unsteady state and steady state longitudinal creep forces was described as two order transfer function of wavelength ratio when sinusoidal short-pitch corrugations had same shallowness factor. The fluctuating part of unsteady longitudinal creep force was calculated according to the fluctuating part of steady longitudinal creep force, thereout, the unsteady longitudinal creep force was calculated. Calculation result shows that under small creep condition, the fluctuating part of unsteady longitudinal creep force decreases in amplitude and phase lag with the growth of wavelength ratio. The bigger wavelength ratio is, the smaller amplitude is, and the more phase lag is. However, the result from steady state theory is independent of wavelength ratio. For unsteady longitudinal creep forces calculated by the transfer function and Kalker 3D rolling contact theory, the waveforms in time domain, the amplitudes and phase spectrums in frequency domain are accordant.More>

2011, 11(2): 24-31. doi: 10.19818/j.cnki.1671-1637.2011.02.005

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Solution methods of rail model in vehicle-track coupling dynamics

ZHANG Jian, JIN Xue-song, XIAO Xin-biao, WEN Ze-feng, WU Chang-hua

Abstract: The computational accuracies and efficiencies of different methods for solving dynamic rail model were investigated with vehicle-track nonlinear coupling dynamics model. The methods were modal superposition method based on analytical expression, modal superposition method based on FEM, and direct integration method based on FEM. Rail was modeled by Bernoulli-Euler beam or Rayleigh-Timoshenko beam, and rail model was divided by different types of elements. The response of vehicle-track coupling dynamics was solved with explicit integration method. Calculation result indicates that the computational time of direct integration method based on consistent mass matrix is 28.8 times than that of modal superposition based on analytical expression when rail is modeled by Bernoulli-Euler beam and track excitation frequency is lower, and the computational accuracies of the methods are nearly same. The response influence of rotatory inertia for Rayleigh-Timoshenko beam in vehicle-track coupling dynamics model can be neglected when rail is modeled by Rayleigh-Timoshenko beam and track excitation frequency is lower. The computational time of modal superposition method based on analytical expression is 64.5% slower than that of hybrid element.More>

2011, 11(2): 32-38. doi: 10.19818/j.cnki.1671-1637.2011.02.006

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Influence of lag time for slave control locomotive on longitudinal coupler forces of 30 000 t train

WEI Wei, YU Zhong-jian

Abstract: The performance of air brake system was got by using brake system simulation method. The coupler forces of 30 000 t train under the service and emergency applications of multi-locomotives with lag times were analyzed by using train dynamics simulation method. The feasibility marshalling of 30 000 t heavy haul train on Datong-Qinhuangdao Railway Line was proposed. The change tendencies of maximum coupler forces at service and emergency applications were analyzed when slave control locomotives had different lag times. Analysis result shows that in the case of full service application, the lag time of second slave control locomotive has a greater impact on coupler force than that of first slave control locomotive, and maximum coupler force increases by 80.2% when slave control locomotive lag time is 5 s. In the case of emergency application, the lag time of first slave control locomotive has a greater impact on coupler force, and maximum coupler force increases by 335.9% when slave control locomotive lag time is 5 s. Coupler force can be controlled within acceptable range when the lag time of slave control locomotive keeps within 4.1 s.More>

2011, 11(2): 39-44. doi: 10.19818/j.cnki.1671-1637.2011.02.007

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Numerical simulation of aerodynamic drag for high-speed train bogie

ZHENG Xun-hao, ZHANG Ji-ye, ZHANG Wei-hua

Abstract: To study the aerodynamic drag properties of high-speed train bogies, an aerodynamics model of train was built.Based on 3D steady compressible N-S equation and turbulent model of k^-ε two equations, the aerodynamics properties of high-speed train running at 400 km·h^-1 were numerically simulated by using finite volume method.The influence of train bottom shapes on bogie's aerodynamic drag was analyzed.Analysis result shows that the flow field structure of bogie region is very complex.Vortices emerge on both the forward and backward bogies.The aerodynamic drags of bogies are different.Under crosswind-free condition, the aerodynamic drag of the first bogie is more than 4 times of the fourth bogie.The aerodynamic drag of bogie takes up more than 20% of whole train aerodynamic drag, and it is more than 40% under crosswind.The maximum differences of bogie aerodynamic drags are more than 30% due to the different shapes of train bottom.The aerodynamic drags of bogies and whole train reduce due to changing train bottom shape appropriately.More>

2011, 11(2): 45-51. doi: 10.19818/j.cnki.1671-1637.2011.02.008

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Robust control of lateral self-powered active suspension for railway vehicle

SONG Peng-yun, ZHANG Ji-ye, ZHANG Ke-yue

Abstract: In order to ensure the stability of lateral self-powered active suspension system with parametric uncertainty for railway vehicle, a robust H∞ controller design approach was proposed based on linear quadratic regulator with cross-product terms. A robust H∞ controller was designed for suspension system model with perturbation. The energy balance condition of self-powered active suspension system with perturbation was analyzed, and the control system was simulated by using MATLAB/SIMULINK. Simulation result indicates that the structure singular peak value of closed-loop system with parametric uncertainty is 0.867 5, and the controller makes self-powered active suspension system stable. The resonant frequency gain of vehicle model reduces by 40 dB, and the vibration isolation performance suspension is improved obviously. The recycled energy in the whole simulation process is 29.5 J, and the energy balance of the system is achieved.More>

2011, 11(2): 52-58. doi: 10.19818/j.cnki.1671-1637.2011.02.009

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Influences of buffer impedance characteristics on dynamics performances for heavy haul train

MA Wei-hua, SONG Rong-rong, JIE Zhang-an, LUO Shi-hui

Abstract: The buffer characteristics of heavy haul train were studied, and the structures and working principles of elastic clay buffer and friction clay buffer were analyzed. On the basis of HXD1 type locomotive, 13A type coupler and two buffers, a dynamics model of 104 t grade traction train with four marshalling locomotives was established, and the influences of the static and dynamic impedance characteristics of two buffers on the dynamics performances of heavy haul train were researched. Simulation result indicates that when heavy haul train conducts cycle braking on long downgrade, the infinite static impedance characteristic of friction clay buffer is beneficial to play buffer action, and the stroke and capacity of friction clay buffer can keep 100% under the static pressure of 900 kN. Friction clay buffer also can satisfy the demand of further dynamic pressure of 1 000 kN, while the buffer stroke is no more than 20 mm. Under the compound effect of static pressure of 900 kN and dynamic pressure of 400 kN, the stroke of elastic clay buffer has reached 60 mm, so elastic clay buffer can't satisfy the demand of more greater impact pressure. On the aspect of dynamic impendence characteristic, two buffers all can satisfy the normal running demand of 104 t grade heavy haul train.More>

2011, 11(2): 59-64. doi: 10.19818/j.cnki.1671-1637.2011.02.010

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Low-noise optimization design of external corrugated floor for high-speed train

SHEN Huo-ming, ZHANG Yu-mei, XIAO Xin-biao, JIN Xue-song

Abstract: Based on the hybrid finite element and statistical energy analysis (hybrid FE-SEA) and the principle of periodic substructure, a acoustic characteristic simulation model of external corrugated floor used in high-speed train was established. According to the transmission loss of external corrugated floor structure, the sound insulation property was evaluated. Corrugated floor structure, corrugated floor structure with top plate, corrugated floor structure with bottom plate, corrugated floor structure with splint were chosen, and the sound insulation properties of the structures were analyzed under different web angles. Calculation result shows that the sound insulation losses of corrugated floor structure and corrugated floor structure with top plate are bigger than the other two structures at every angle. Corrugated floor structure with bottom plate has the worst sound insulation property, but corrugated floor structure with top plate has the best sound insulation property, and their sound insulation difference is 6.9 dB while the web angle is 55°. Through the analysis of sound insulation loss, the best combinations of external corrugated structures and web angles under different frequency noises are obtained, which can provide evidence for the low-nosie structure design of external corrugated floor for high-speed strain.More>

2011, 11(2): 65-71. doi: 10.19818/j.cnki.1671-1637.2011.02.011

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Characteristics and structure analysis of urban slow mode traffic network

LI Cong-ying, MA Rong-guo, WANG Yu-ping, WANG Zhao-fei

Abstract: Based on complex network theory, urban slow mode traffic network was converted into topology structures in space L and space P. Through analyzing the basic property indexes of complex network, such as average path length, clustering coefficient and degree distribution, the network type was ascertained, and the hub points were found in space L. Through analyzing the structure characteristic indexes of complex network in space P, such as node degree, closeness and betweenness, and using the fuzzy cluster method, a network structure classification method of urban slow mode traffic complex network was put forward, and the slow mode traffic properties in Weinan were analyzed. Analysis result shows that the small-word characteristic of slow mode traffic network in Weinan center zone indicates the better reachability of traffic network. The important degrees of urban slow points can be reflected by using the sacle-free network characteristics of weighted complex network in space L. Through analyzing the structure characteristic indexes of complex network in space P, the structure classes of urban slow mode traffic network can be classified as slow corridors, slow passages and slow leisure ways by using the fuzzy cluster method.More>

2011, 11(2): 72-78. doi: 10.19818/j.cnki.1671-1637.2011.02.012

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Calculation model of maximum number for gathering passenger at railway passenger station

ZHANG Tian-wei, GAO Gui-feng, LUO Yu-ping, NIE Lei

Abstract: Based on considering passenger trip habits and train delays, a computation model of maximum number for assembling passengers at railway passenger station was proposed. In the model, when trains' departure times were between 6:00-9:00, passengers reached railway passenger station in advance 5-60 min. When trains' departure times were after 21:00, passengers reached railway passenger station at 19:00-21:00. The higher train grade was, the higher its priority of delay adjustment was. The delay time was direct proportion to the running time. Computation result shows that under considering passenger trip habits, the computation period of time for maximum number of assembling passengers accords to the actual period of time. Under considering train delays, the maximum number of assembling passengers increases by above 50%. So, the design coefficient of the maximum number are suggested, its value should vary from 1.3 to 1.8 when the change of running density of trains varies from small to big.More>

2011, 11(2): 79-83. doi: 10.19818/j.cnki.1671-1637.2011.02.013

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Real-time prediction model of arrival time for floating transit vehicle

SUN Di-hua, LAI Yun-bo, LIAO Xiao-yong, ZHAO Min, LIU Wei-ning

Abstract: According to the real-time GPS data of floating transit vehicle, the effects of road section average speeds, bus stations and traffic lights were considered, and a novel prediction model of bus arrival time was proposed.The precision of prediction model was improved by estimating arrival time to the nearest downstream station and judging the effectiveness of GPS data on raod section.The prediction model was tested and verified by using the transit vehicle GPS data of Chongqing City.Calculation result indicates that the arrival time of floating transit vehicle to the downstream station can be real-time predicted by using the model, the prediction precision is better than the existing methods, the prediction error is less than 9% in peak periods and is about 6% in non-peak periods, and the prediction model has good adaptability to the various of traffic conditions.More>

2011, 11(2): 84-89. doi: 10.19818/j.cnki.1671-1637.2011.02.014

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Driving risk evaluation and speed control in passageway areas of freeway

YAN Ying, SHENG Yan-ting, YUAN Hua-zhi, LIU Hao-xue

Abstract: The traffic flow characteristics and accident reasons in the passageway areas of freeway were analyzed.Based on vehicle critical deceleration and unsafe degree, risk level was changed from two dimensional vector to one dimensional scalar.Braking decelerations and unsafe density indexes were put forward as the driving risk evaluation indexes of passageway areas, and a driving risk evaluation model was established.According to safety risk management regulations and human-mechanism engineering theory, risk grades and evaluation standards were dertermined.On the basis of many experiment data, the suggested values of main line driving control standards in passageway areas of freeway were proposed.Analysis result shows that when speed is not limited, the driving risk of outlet area is middle.When speed is limited at 65 km·h^-1, the driving risk of outlet area is low, and the average risk value is smallest.The peak value of unsafe density index reduces from 0.112 to 0.064, and decreases about 42.86%.When speeds are limited at 55, 50 km·h^-1, the risk of outlet area is high, and the peak values of unsafe density indexes rise to 0.125 and 0.121 respectively.Obviously, the limit measure of 65 km·h^-1 is most effective.More>

2011, 11(2): 90-96. doi: 10.19818/j.cnki.1671-1637.2011.02.015

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Multi-level fuzzy comprehensive evaluation method of lead performance for high-speed railway

ZHANG Teng, MA Rong-guo

Abstract: The evaluation index system of lead performance for high-speed railway was put forward, and a multi-level fuzzy comprehensive evaluation model was established.In the model, the fuzzy factors were quantized, the index weights were rationally distributed, and the fuzzy relationship matrices and membership functions of the indexes were set up.The consistency of comparison matrix was checked, and the validity of the lead project was evaluated by using the effective principle of maximum membership degree.Evaluation result shows that the comprehensive evaluation value of the lead scheme A is 11.214, is maximum, which accords with actual decision-making project, so the lead scheme A is better, and the model is credible.More>

2011, 11(2): 97-101. doi: 10.19818/j.cnki.1671-1637.2011.02.016

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Blocking cost model of urban rail transit

CHEN Jin-jie, WANG Xing-ju, GAO Gui-feng

Abstract: A generalized life cycle cost model was presented in order to solve the selection and decision of construction schemes for urban rail transit, and the time value of capital was considered. The external cost components of urban rail transit were analyzed, the blocking cost concept of urban rail transit was introduced, and a blocking model was developed. A case study of line 1 for Shijiazhuang urban rail transit was made, and the generalized life cycle costs of different laying modes were calculated quantificationally. Calculation result shows that the life cycle cost of line on the ground is 7.216 billion yuan according to traditional life cycle cost method, and it is lowest. The generalized life cycle cost of underground line is 17.345 billion yuan according to generalized life cycle cost method, the total cost is lowest, and the underground line is the best scheme.More>

2011, 11(2): 102-107. doi: 10.19818/j.cnki.1671-1637.2011.02.017

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Enhanced handover scheme with shared-relay stations in GSM-R network

FANG Xu-ming, YANG Chong-zhe, LU Ling-hui, DI Cheng

Abstract: In order to improve the successful handover probability of GSM-R (GSM for railway) system, an enhanced handover scheme with shared-relay stations was put forward. In the scheme, shared-relay stations were applied to improve the signal quality of target base stations in the signal overlapping region among adjacent base stations and to separate the received mixed signals from different base stations, which could decrease the handover misjudgment resulted from signal fluctuation. Simulation result shows that the scheme can trigger handover appropriately in advance about 500 m, so that there is longer distance for completing handover process when train is traversing through the overlapping region. Because of better signal quality, ping-pong effect eliminates, handover failure probability reduces to 10^-6, thereby, successful handover probability increases. Meanwhile, considering the system interference, shared-relay stations can not be used in the network with the less reuse factor than 2.2 tabs, 9 figs, 13 refs.More>

2011, 11(2): 108-113. doi: 10.19818/j.cnki.1671-1637.2011.02.018

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Cellular automata model of urban traffic emergency evacuation and rescue

YANG Zhao-sheng, GAO Xue-ying, SUN Di

Abstract: The effects of vehicle delay on the emergency evacuation and rescue decision-making of all traffic flow conflicts within cities were analyzed.An intersection control parameter was introduced into the exciting simulation model of emergency evacuation and rescue, and the model was based on cell transmission model.A simulation model of emergency evacuation and rescue was built under intersection emergency control.In the improved model, the weighted travel time of emergency evacuation and rescue in planning horizon was minimized, and contraflow strategy was introduced.Simulation result shows that because giving way to high-priority traffic flows G3 and G4, the average travel times of low-priority traffic flows G1 and G2 increase by 10.0 s and 11.1 s respectively, which accords with the actual circumstance of urban emergency evacuation and rescue.After the implementation of contraflow strategy, the travel times of beneficial traffic flows G2 and G4 decrease by 6.5 s and 6.0 s respectively.So the model and contraflow strategy are feasible.More>

2011, 11(2): 114-120. doi: 10.19818/j.cnki.1671-1637.2011.02.019

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Automatic acquisition system of vessel traffic conflict data in precautionary area

LI Song, KONG Fan-cun, GUAN Ke-ping

Abstract: Traffic conflict research method was introduced, and a solving scheme of automatic acquisition for vessel traffic conflict data in ships' routing precautionary areas was proposed based on ECDIS, AIS and support vector machine (SVM). In the solving scheme, SVM classification model was acquired through training study of sample data, and the conflict degree was identified by using the model. SVM software package and SVM classification model were embedded in ECDIS, and the automatic acquisition system of vessel traffic conflict data was achieved combined with the real-time data of AIS. The vessel traffic conflict data of precautionary area A for Yangtze estuary ships' routing in 72 h were acquired by using the system. Example result shows that the traffic flow and vessel traffic conflict data of precautionary area A in 72 h are 681 and 327 respectively. Severe, moderate and mild conflicts account for 10.7%, 21.4% and 67.9% of the total respectively. The running of the system is steady, and vessel traffic conflict data can be acquired and processed automatically.More>

2011, 11(2): 121-126. doi: 10.19818/j.cnki.1671-1637.2011.02.020

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