2014 Vol. 14, No. 1

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Road and railway engineering
Research status summary of asphalt pavement technology on cement concrete bridge deck
HUANG Xiao-ming
Abstract: Through the analysis and summary on domestic and abroad research statuses and development trends of asphalt pavement technology on cement concrete bridge deck, the influences of concrete bridge types in different countries and traffic load circumstances on asphalt pavement technology were studied, especially on the mechanism of asphalt pavement diseases and the classification method, pavement structure combination, pavement material and pavement structure design. Analysis result shows that the durability of asphalt pavement is not entirely determined by the strength or excellence of pavement material, but more by the adaptabilities of pavement structure and material to bridge structure and concrete bridge deck. Integrated design of pavement and waterproof, construction quality control and evaluation methods are the keys to ensure the durability of pavement. The green materials of pavement for noise reduction, ice and snow melting, and easy regeneration are worth advocating. Asphalt pavement construction quality control system should be established and improved. Asphalt pavement typical structure with high humanization is worth studying.More>
2014, 14(1): 1-10.
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Mix proportion design method with multiple indexes for continuously reinforced concrete
ZHANG Hong-liang, CHEN Jiang, SU Man-man, LI Ning-li
Abstract: The sensibilities of continuously reinforced concrete pavement (CRCP) performances on concrete parameters such as compressive strength, drying shrinkage strain and temperature shrinkage coefficient were analyzed by using MEPDG software. The influences of mix proportion parameters of cement content, water-cement ratio etc on pavement design parameters were studied through laboratory tests. According to balanced design theory, the mix proportion design method with multiple indexes for continuously reinforced concrete was set up. The appropriate scopes of mix proportion parameters were recommended, the regression formulae of water-cement ratio with drying shrinkage strain and temperature shrinkage coefficient were established, and the formula of flexural-tensile strength and compressive strength was also established. Analysis result indicates that compressive strength, drying shrinkage strain and temperature shrinkage coefficient are fitted to be control indices of mix proportion design method for continuously reinforced concrete. The mass content of cement slurry should be less than 22%. Nominal maximum aggregate size should be 19.0-26.5 mm. It is shown that the concrete designed according to the mix proportion design method with multiple indexes can better satisfy the performance requirement of CRCP.More>
2014, 14(1): 11-17.
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Calculation methods of bearing capacities of eccentrically loaded concrete columns
CHEN Bao-chun, LIN Shang-shun
Abstract: By the application of the calculation methods of masonry columns and plain concrete columns in Codes for Design of Highway Masonry Bridges and Culverts (JTG D61—2005) and the calculation methods of reinforced concrete columns in Codefor Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts (JTG D62—2004), the loadcarrying capacities of 3 reinforced concrete arch bridges with the spans of 70, 160, 420 m were calculated respectively. The change rules of the bearing capacities of reinforced concrete columns were studied considering slenderness ratio, eccentricity, reinforcement ratio, and etc. The parameter ranges of the equivalent beam-column of concrete arches and the ultimate bearing capacities of masonry columns, plain concrete columns and reinforced concrete columns were analyzed. Analysis result shows that the bearing capacities calculated by JTG D61—2005 are greater than those calculated by JTG D62—2004 when reinforced concrete arches with low reinforcement ratio are treated as equivalent beam-column. For reinforced concrete columns with low reinforcement ratios and high slenderness ratios and eccentricities, the bearing capacities calculated by the formulas of reinforced concrete columns are smaller than those calculated by the formulas of masonry columns or plain concrete columns. Thus it can be seen that there areunreasonable factors in the calculation methods of eccentrically loaded concrete columns in two codes, which should be improved.More>
2014, 14(1): 18-25.
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Time-dependent variation distribution of fire temperature for concrete hollow thin-walled pier affected by flame fluid
ZHANG Gang, HE Shuan-hai, WANG Cui-juan
Abstract: For the structure response of the coupled variation of air current in fire field and flame temperature space, considering the effect of air current speed as well as the interaction effect of flame space and structure height, the surrounding fire model in flame fluid field was created. The temperature of flame fluid field was calculated by using time increment iteration method. The comprehensive boundary control equation and the relation between convection heat exchange and air current speed were studied. The temperature distribution statuses of facing-fluid side and lateral-fluid side in fluid field were analyzed, the surrounding fire scene of concrete hollow thinwalled pier was studied, the coupled model of flame fluid field was proposed, the time-dependent variation distribution law of fire temperature for concrete hollow thin-walled pier affected by flame fluid was revealed. Analysis result indicates that when fire time is 120 min and air current speed is 3 m·s-1, the temperature near fire source is about 100℃ higher than that at other air current speeds, the influence of air current speed on fire source temperature is nonlinear. Thedistribution depth of high temperature layer (higher than 500℃) on facing-fire side is only 7 cm, the outer facing-fire side concrete of hollow thin-walled pier strips easily under vertical load. Temperature on facing-fluid side is much higher than temperature on lateral-fluid side, temperature on far side of fire does not change. The distribution domains of different temperatures can be changed with the variation of air current speed in steady low fluid field, and the high temperature area on facing-fire side can be enlarged.More>
2014, 14(1): 26-34.
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Back-filled grouting compaction model of shield tunnel based on spherical cavity expansion
YE Fei, CHEN Zhi, GOU Zhang-fei, MAO Yan-fei, LIU Qin
Abstract: In order to study the compaction effect of back-filled grouting for shield tunnel, it was assumed that the grout expanded as a semi-sphere in clay stratum during compaction stage. The expansion process of spherical grouting was theoretically deduced by using elastic plastic theory, the back-filled grouting compaction model of shield tunnel was set up. The expansion rates of grouting, the plastic zone of soil mass and the pressure of grouting on segment were calculated. The effects of different parameters such as grouting pressure and the elasticity modulus, cohesive force and internal friction angle of surrounding soil on the pressure load of segment were analyzed. Analysis result shows that the pressure of grouting on segment increases with the increase of grouting pressure and soil mass Poisson's ratio, and decreases along with the increase of soil elastic modulus, cohesive force and internal friction angle. The pressure of grouting on unit area segment do not change along with the change of grouting pressure and soil characteristics. The pressure stress of back-filled grouting on segment becomes smaller and smaller when it is farther and farther away from grouting hole.More>
2014, 14(1): 35-42.
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Transportation vehicle engineering
Effect of bionic rhombic surface texture on frictional noise of high-speed train
WANG Jiu-gen, CHEN Shi-hong, WANG Qing-jiu
Abstract: In order to reduce the frictional noise of gas-solid interface for running high-speed train, a noise analysis model of gas-solid interface was established by using the rhombic surface texture to mimic the surface texture of jaws shin. The compressible N-S equation was solved by using unstructured hybrid grid and k-ε model, and the noise distribution was obtained based on broadband noise source. Numerical result demonstrates that the noise significantly reduces as result of eddy current in the rhombic structure, and the corresponding noise distribution also changes. The air frictional noise of running train increases with the increase of the speed. Compared with the smooth surface, the maximum reducing value of noise intensity for the surface texture with optimal diagonal ratio is 24 dB and the value with optimal depth to side ratio is 20 dB.More>
2014, 14(1): 43-48.
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Small-scale similarity model of maglev-guideway coupling vibration
WANG Hui, SHEN Gang
Abstract: Simplified as a model composed of single magnet and Bernoulli-Euler beam, the maglevguideway coupling vibration system with 5-state-variable feedback controller was designed to study the dynamics performances of the system in the time and frequency domain. A small-scale model of single magnet-guideway coupling vibration system was established based on the similarity theory, its similarity performances were studied, and the similarity relationship of the dynamics systems was analyzed. Study result shows that the maglev control method, calculating the controller output with the vibration informations of guideway's low order mode and magnet, is effective and can keep the system stable. The step response of the system indicates that the developed controller can stabilize the system in 0.27 swith the overshot 2%. The first 3 order modes can be used to accurately describe the dynamics characteristics of coupling vibration system. For analyzing the lower frequency characteristics of the system, the first 1 order mode is sufficient when the large difference among the lower frequencies exists. The small-scale model obtained according to the similarity theory is coincident with the original model in the dynamics performances.More>
2014, 14(1): 49-56.
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Fault feature analysis of high-speed train bogie based on empirical mode decomposition entropy
QIN Na, WANG Kai-yun, JIN Wei-dong, HUANG Jin, SUN Yong-kui
Abstract: A novel method of feature extraction was proposed by combining ensemble empirical mode decomposition (EEMD) and five entropies based on the characteristics of vibration signal for high-speed train bogie in failure station. Firstly, vibration signal was decomposed by EEMD to avoid mode mixing effectively. Secondly, EEMD entropy feature was calculated for describing the complexity of intrinsic mode functions (IMFs). Vibration signals were obtained under four typical working conditions including normal condition, air spring fault, lateral damper fault and yaw damper fault. There were 280 sample data including 60% training samples and 40% test samples. Analysis result shows that the method is good adaptivity for unselecting basis functions and decomposition levels. The recognition rate is above 95% at the running speed of 200 km·h-1. Therefore, the feature extraction method is effective to analyze the vibration signal of high-speed train bogie in fault station.More>
2014, 14(1): 57-64.
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Joint estimation method of key parameters for automotive active safety
SONG Xiang, LI Xu, ZHANG Wei-gong, CAI Feng-tian, WU Ming-ming
Abstract: According to the requirements of automotive active safety system, ajoint estimation method of key parameters for automotive active safety including automotive longitudinal velocity, lateral velocity and road friction coefficient was proposed. Based on automotive dynamics model with 3 degrees of freedom and brush tire model, the extended Kalman filter models under different road friction coefficient conditions were established. Automotive longitudinal velocity and lateral velocity were adaptively estimated by using the interacting multiple model, and the road friction coefficient could be real-timely estimated based on the calculated model probabilities. Calculation result shows that the method can accurately estimate automotive longitudinal and lateral velocities under different road friction coefficient conditions, the estimation error rates are less than 1% and 5% respectively. Compared with extended Kalman filter method, the estimation error of automotive velocity estimated by using the method reduces by more than 50%. When road condition mutates, the road friction coefficient can be real-timely estimated, the estimation error is less than 0.1, and the response time is less than 2 s.More>
2014, 14(1): 65-74.
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Transportation planning and management
Path optimization model and algorithm of multimodal transport for long and bulky cargo
LEI Ding-you, YOU Wei, ZHANG Ying-gui, PI Zhi-dong
Abstract: Based on the view of feasibility and rationality, the path optimization influence factors of multimodal transport for long and bulky cargo were analyzed. The minimum transport time, mileage and cost were taken as objective functions, the line boundary, bridge bearing capacity and lifting equipment capacity were taken as constraint conditions, and the original path optimization model of multimodal transport for long and bulky cargo was set up. By considering the transformation characteristics of constraint conditions, the original model was extended and optimized, two-dimensional sequence coding strategy was designed, and the extensional model was solved by using genetic algorithm. Calculation result shows that by using the extensional model and genetic algorithm, the optimal transport time, mileage and cost are 12.5 d, 1 116 km and 581 800 yuan respectively. By using the extensional model and simulated annealing algorithm, the optimal transport time, mileage and cost are 15.5 d, 1 131 km and 677 400 yuan respectively. By using single-railway transport mode and genetic algorithm, the optimal transport time, mileage and cost are 12.7 d, 1 152 km and 565 000 yuan respectivelg. By using the extensional model and genetic algorithm, the integrated optimization degree rises by 52.22% and 8.95% compared with the other 2 conditions. Obviously, the extensional model is feasible, and genetic algorithm is effective.More>
2014, 14(1): 75-83.
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Influence of airport coach service reliability on airport market share during market cultivation period
YANG Zhong-zhen, LU Jing, BAO Hong-li
Abstract: Based on the cumulative prospect theory, the choice behavior habit of passenger on airport was analyzed. According to the habit damping rule, the change process of choice behavior for passenger on airport was gotten. According to the change process of choice behaviors for all passengers during market cultivation period, the increase curve of market share was gotten after the airport coach service was carried out. The air trip data of Wuxi City in 2006-2009 were taken as an example, the influence of airport coach service reliability on airport market share during market cultivation period was analyzed. Analysis result indicates that after airport coach from Nanjing Lukou International Airport runs, the passengers who choose Shanghai Pudong International Airport will change to choose Nanjing Lukou International Airport after experiencing more than 8 trips when the choice habit strength equals to 0.52. The market share of Nanjing Lukou International Airport reaches the stationary value after the cultivation period of 26 months. When the fluctuation range of running time for airport coach decreases from ± 15 minto ± 5 min, the market cultivation period for Nanjing Lukou International Airport will reduce by 12 percent, when the the fluctuation range increases from ±15 min to ±25 min, the market share is around 20 percent. The effects of new service from Nanjing Lukou International Airport will not show immediately but gradually appear with time. The market share will increase as the reliability of airport coach increases.More>
2014, 14(1): 84-89.
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Optimal strategy of container vertical transportation energy structure conversion on port yard
PENG Yun, WANG Wen-yuan, SONG Xiang-qun, TANG Guo-lei
Abstract: Based on the dynamic programming theory, the minimum total cost during crane lifetime was taken as objective function, the carbon emission amount and investment cost were taken as constraint conditions, the dynamic changes of crane operation cost and carbon emission were considered, and the dynamic discrete programming model of container vertical transportation energy structure conversion on port yard was established. The athwart order method was carried out to solve the model, and the optimal strategy of crane energy structure conversion was determined. Calculation result shows that when rubber tire gantry (RTG) is 1 year old, the energy structure conversion should be completed at the start of the sixth year, and the total cost during the total lifetime of single crane under the optimal strategy is 9 376 600 yuan. When RTG is 2 years old, the energy structure conversion should be completed at the start of the fifth year, and the total cost during the total lifetime of single crane under the optimal strategy is 9 585 900 yuan. When RTG is equal to or older than 3 years, the energy structure conversion should be completed at the start of the second year, and the total cost during the total lifetime of single crane under the optimal strategy is 9 673 300 yuan. When the carbon limit value is less than or equal to 100 t, RTG energy structure should be converted immediately. When the carbon limit value is more than 400 t, the energy structure conversion should be completed at the start of the sixth year, and the constraint of carbon emission can be ignored. Because the carbon emission cost only accounts for 0.6-0.7 percent of operation cost and does not affect the decision greatly, it is advised to reduce carbon emission by increasing carbon tax or controlling carbon limit value.More>
2014, 14(1): 90-96.
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User cost model of highway work zone during discrete periods under influence of uncertain factors
YANG Qi, YANG Yun-feng, WU Da-yong, ZHAO Xian-wei
Abstract: The traffic situation of highway work zone during discrete periods was analyzed. By dispersing the work periods, the relationships between the capacities of work zones and user costs during different discrete periods were compared, and the calculation models of user costs during corresponding periods were set up. The uncertain factors of user cost for highway work zone were analyzed. Based on the probability distributions of uncertain factors, the fluctuation scope of user cost was predicted by using Monte Carlo simulation and verified by the example of Qinglian Highway. Calculation result indicates by using the proposed model, the average user cost under the day-time work scheme is 193 148 021 yuan, and the maximum and minimum costs are 466 820 060, 117 342 849 yuan respectively. The average user cost under the night-time work scheme is 1 795 047 yuan, and the maximum and minimum costs are 3 443 468, 1 417 274 yuan respectively. It is found that the application of proposed model can show the influences of uncertain factors well.More>
2014, 14(1): 97-102.
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Traffic information engineering and control
Bi-level programming model of timing optimization for multiple bus priority intersection
ZHU Xiao-ning, LONG Bing
Abstract: Induction signal control based on bus priority had negative effects on vehicles in nonpriority phases. In order to equilibrate the loss of non-priority phases, as well as to reduce the passenger delay at the intersection and the downstream stations, a bi-level programming model of signal timing optimization for multiple bus priority intersection was proposed. In the upper model, priority strategies were optimized based on the intersection delay and the passenger queuing delay at downstream stations. In the lower model, the equilibrium process of green loss was described based on the calculation of acceleration-deceleration delay at the intersection. With priority strategies as decision-making variables, the influence of priority strategies was introduced to the lower model. The solution algorithm was designed by using the Gauss-Seidel iterative method. An application example was analyzed. Analysis result indicates that after signal timing optimization, total passenger delays at the intersection and downstream stations in the period reduces by 23 576.12 s. Besides, the vehicle acceleration-deceleration delay at the intersection reduces by 62.87s. Bi-level programming model ensures the overall efficiency at the intersection under consideration of bus priority.More>
2014, 14(1): 103-111.
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Dynamic control of train interval based on real-time calibration of safe headway
PAN Deng, ZHENG Ying-ping
Abstract: The relationship between train interval and its following behavior was analyzed. When the steady-following state of high-speed train was broken, the dynamic control of train interval was described by using the formal modeling tool of Petri nets. For the CTCS-4 level train control system, a fitting function of the minimum safe headway changing with the current velocity of following train within the full-range velocity field was constructed by using numerical analysis method, and the constructed fitting function was used for the behavioral quality evaluation of following train. The dynamic control model of train interval was established based on the evaluation of train following behavior, and the model was simulated and verified. Simulation result indicates that during the period of train following system operating from a safe and efficient steady-following state with a velocity of 200 km·h-1 and a train interval of 5 849.18 mto another steady-following state with a velocity of 380 km·h-1, the dynamic control of train interval is accomplished well by the behavioral adjustment of following train, and the train interval is only 358.00 mlonger than the safe headway when a new steady-following state is realized at the velocity of 380 km·h-1, which means that a new safe and efficient steady-following state is established. When the preceding train stops abruptly in emergency, under the action of control law, the following train takes a corresponding measure to reduce its own velocity for movement in safety, efficiency and smoothness until it stops completely. The simulation results verify the effectiveness and feasibility of control method for safe and efficient train following operation.More>
2014, 14(1): 112-118.
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Adaptive transmission mode selection strategy of vehicle communication access system
CHEN Ting, ZHAO Xiang-mo, DAI Liang, ZHANG Li-cheng
Abstract: In order to improve the capability of intelligent transportation system (ITS) for effective transmitting of all kinds of information service flows, the technologies of adaptive modulation and coding (AMC) and orthogonal frequency division multiple access (OFDMA) were introduced into the vehicle communication access subsystem, and an adaptive transmission mode selection strategy was proposed. When the vehicle ran in a special geographic region or at a driving speed below 60km·h-1, the process of adaptive transmission mode selection would be triggered by the vehicle communication access system. Compared to the fixed SNR switching thresholds of AMC transmission modes of the typical strategies, the switching thresholds of the proposed strategy were variable and determined by the target packet error rate of ITS information service flow. In this case, different modulation and coding mode levels were probably used for the same access channel condition with different kinds of information service flows transmitting toobtain higher effective data transmission rate. All kinds of service flow target packet error rates and system average effective data transmission rates of the selection strategy were evaluated by using mathematical analysis. Analysis result indicates that the proposed strategy can make better tradeoff between transmission reliability and efficiency. When the target packet error rates of the first, second and third kind of ITS information service flow are 10-6, 10-5 and 10-2 respectively, the proposed strategy is recommended to improve the system average data transmission rate of the typical strategy by 8% with fulfilling the transmission reliability requirements at the same time.More>
2014, 14(1): 119-126.
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