2013 Vol. 13, No. 4

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Characteristic of crack spacing for continuously reinforced concrete pavement
ZHANG Shu, HU Sheng-neng, ZHAO Hong-duo, ZHAO Dui-jia
Abstract: The characteristics of average crack spacing models for continuously reinforced concrete pavement (CRCP) in AASHTO—1993 and Mechanistic-Empirical Pavement Design Guide (MEPDG) were analyzed.A total of 1 171crack spacing data were collected from 29CRCP experimental sections.Classifying, statistical analysis, distribution fitting and variance analysis were conducted by using the data.The parameters of AASHTO—1993and MEPDG models were determined respectively, and two models were validated by using the data.Research result shows that cracks can be classified into six types according to the patterns, and CRCP crack spacing distribution is subject to four-parameter Dagum distribution.The differences of CRCP average crack spacings for different slab thicknesses at the same reinforcement ratio are not significant.AASHTO—1993model overestimates average crack spacing with an error of 0.13m, MEPDG model tremendously underestimates average crack spacing with an error of 1.7m.More>
2013, 13(4): 1-7. doi: 10.19818/j.cnki.1671-1637.2013.04.001
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Experiment of active deicing and snow melting pavement coating with environmental friendly and long-term action
YAO Yun-shi, CHEN Tuan-jie, XIANG Hao, WANG Bao-lei, JIANG Song-li
Abstract: The mechanism of active deicing and snow melting pavement coating with environmental friendly and long-term action was analyzed.The comparative experiment methods of various deicing and snow melting materials were used, and the experiments of snow melting, freezing rain, and secondary icing under artificial environment were conducted.The environmental performance was analyzed through the experiments of carbon steel bar corrosion and watering clover, and the deicing and snow melting performance of road was evaluated in an experimental section.Analysis result shows that when the amount of active deicing and snow melting pavement coating is more than 0.6kg·m-2, the effect of snow melting is perfect, and one-time construction of the coating can be used repeatedly.Freezing rain and secondary icing can be well inhibited by the coating.The active deicing and snow melting pavement coating has little harm to structures and vegetations, and has good environmental performance.One-time construction of the coating can deice and melt snow several times, and the ability of repeated snow melting can meet the long-term requirements for a snowing season.More>
2013, 13(4): 8-15. doi: 10.19818/j.cnki.1671-1637.2013.04.002
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Influence of freezing speed on physical and mechanical properties of freezing-thawing loess
ZHOU Zhi-jun, YANG Hai-feng, GENG Nan, YE Wan-jun
Abstract: Freezing speed was set to 3.33, 1.67, 1.11, 0.83℃·h-1 respectively, and freezing-thawing cycles were conducted on soil samples with different water contents under closed condition.The water contents, dry densities, liquid-plastic limits, shear strengths and compressibilities of soil samples under different freezing speeds were tested, and the influence rules of freezing speed on the physical and mechanical properties of freezing-thawing loess were analyzed.Test result indicates that the water contents of soil samples after freezing-thawing cycle are larger than those of initial soils, and the growth of water content decreases with the increase of freezing speed.When water contents are lower, the influences of freezing speed on the dry densities of soil samples are less.When water contents are higher, the dry densities of soil samples decrease with the increase of freezing speed.The liquid limits of soil samples increase with the increase of freezing speed, and plastic limits change little.Cohesive force increases with the increase of freezing speed, and the change rule of internal friction angle with freezing speed is closely related with water content.The compressibility of soil sample after freezing-thawing cycle is higher than that of unfrozen soil, and compression modulus increases with the increase of freezing speed.More>
2013, 13(4): 16-21. doi: 10.19818/j.cnki.1671-1637.2013.04.003
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Impact response analysis of heavy vehicle passing bridge-tunnel section
CHAO Wan-li, LI Xu-mei, WANG Xing-hua
Abstract: The rotation and overturn of vehicle in longitudinal direction were considered, and the process of heavy vehicle passing bridge-tunnel section was regarded as forced oscillation under certain initial condition.Based on D'Alembert principle, the calculating model of vehicle-road dynamic coupling was built, and vibration equation was given.The impact response of vehicle was analyzed by using Laplace transform, the change law of maximum impact force of vehicle on road was got.The influences of vehicle load, goods position, vehicle speed, difference settlement on vehicle impact response were researched.The test acceleration value was obtained, and the calculated result of acceleration was verified.Analysis result shows that this impact forces between vehicle and road increase with the increases of difference settlement, vehicle speed and load, the influences from big to small in order are vehicle load, difference settlement, vehicle speed.The goods position has little influence on vehicle impact force.More>
2013, 13(4): 22-28. doi: 10.19818/j.cnki.1671-1637.2013.04.004
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Computing method of bridge impact factor based on weighted method
ZHOU Yong-jun, CAI Jun-zhe, SHI Xiong-wei, ZHAO Yu
Abstract: A simply supported beam highway bridge was taken as an example, the half vehicle model with four-degree-of-freedom was employed to set up vehicle-bridge coupled vibration function, and the time-history curves of dynamic deflection and strain at mid-span under different vehicle velocities were calculated.The impact factors (IM) calculated by traditional definition method, experiment method and current code provisions were compared, the first two methods were revised to reflect the maximum dynamic response of bridge.According to the calculation principle of the maximum internal force for girder under moving load, the weighted method was utilized to replenish the first two methods.Analysis result shows that the IMs calculated by traditional definition and experiment methods are less than those in General Code for Design of Highway Bridges and Culverts (JTG D60—2004).The average value of IMs obtained at the maximum dynamic response of time-history curves doubles the first two methods, and its maximum IM is 37%less than code provision.Deflection IMs calculated by traditional definition method are greater than strain IMs, but deflection IMs calculated by experiment method are mostly less than strain IMs.The IM calculated by traditional definition method and weighted method is 16% greater than code provision.The weighted method combining with experiment method reflects the whole impact course of bridge caused by moving load, and it is stable when calculating IM.More>
2013, 13(4): 29-36. doi: 10.19818/j.cnki.1671-1637.2013.04.005
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Theoretical study of longitudinal connection for rubber floating slab track of subway tunnel
XU Qing-yuan, FAN Hao, MENG Ya-jun, ZHOU Xiao-lin, SHI Cheng-hua
Abstract: A coupling dynamics model of subway train, rubber floating slab track and tunnel was established, its corresponding program for coupling dynamic simulation was developed by MATLAB software, and the calculation result of coupling dynamic simulation program was verified by ANSYS software.With the developed coupling dynamic simulation program, a B-type subway train with a speed of 80km·h-1 was taken as an example, when it past through rubber floating slab track on tunnel with 3 kinds of floating slab lengths and 5 kinds of rubber stiffnesses, the influence of longitudinal connection form of rubber floating slab on the dynamic characteristics of coupling system was calculated.Calculation result shows that longitudinally articulated floating slab has little influence on the dynamic characteristics of each vehicle component, the maximum wheel-rail force, the dynamic characteristics of rail, the dynamic characteristics of rubber mat, and the dynamic characteristics of tunnel, and the influence is less than 10%.When floating slab is longitudinally articulated, the vibration acceleration of floating slab decreases significantly, but the maximum positive bending stress of floating slab increases to a certain extent.When the length of floating slab is longer and the stiffness of vibration-reduced rubber mat is lower, after the floating slab is longitudinally articulated, the maximum fastener tensile force near the joint of two neighboring floating slabs decreases significantly, and the decrease amplitude may exceed 80%.When the length of floating slab is 1.25 m, it is not necessary for the floating slab track to be longitudinally articulated, but when the length of floating slab is 5.00mand the stiffness of vibration-reduced rubber mat is less than 0.01N·mm-3, the floating slab track should be longitudinally articulated.When the length of floating slab is 31.25m, the floating slab track should be longitudinally articulated if the stiffness of vibration-reduced rubber mat is less than 0.02N·mm-3.More>
2013, 13(4): 37-44. doi: 10.19818/j.cnki.1671-1637.2013.04.006
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Bogie rotation resistance torque characteristics of passenger car
SHI Huai-long, WU Ping-bo, LUO Ren
Abstract: The mathematical model of railway passenger car was established to analyze the rotation motion between bogie and carbody.The bogie rotation resistance factor formula was built for the vehicle with air springs bogies.Laboratory test was used to measure the resistance factor to verify mathematical model and calculation results.The distribution rule of bogie rotation resistance factor was summarized for motor and trailer car under different loading conditions.The influence of air spring state on the resistance factor was analyzed.Analysis result shows that the theory calculation result is slightly smaller than the test result for air springs in inflated and overinflated states, and the maximum error is 0.02, which is resulted from that the dynamic stiffness change of air spring at different rotation velocities and other suspension components'influence in theory calculation are ignored.The greater the rotation angle and the rotation velocity are, the greater the rotation resistance factor becomes.The resistance factor at 1.0 (°) ·s-1 is much greater than that at 0.2 (°) ·s-1, and the extreme error is 0.047.In the deflated state of air spring, the test result is bigger than the calculation result, and the difference increases with the rotation velocity.The air spring in over-inflated state has little effect on the rotation resistance factor.In the deflated state of air spring, for trailer car of tare load, the rotation resistance factor reaches its most dangerous value 0.093.More>
2013, 13(4): 45-50. doi: 10.19818/j.cnki.1671-1637.2013.04.007
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Comparison method of energy transfer characteristics for fault detection of vehicle suspension spring
DING Jian-ming, LIN Jian-hui, ZHAO Jie, HUANG Chen-guang
Abstract: The frequency shift characteristics of suspension transfer function under different spring stiffnesses were analyzed, and a new dynamic detecting method of vehicle suspension spring fault was developed.The vertical vibration accelerations of car body and bogie at the locations installed with suspension springs were respectively decomposed by seven-layer harmonic wavelet packet, and the eight low scales energies were calculated.The suspension's scale energy transfer characteristics were got through the division of car body and frame acceleration energies in each scale.The comparison method of suspension's scale energy transfer characteristics in adjacent periods was constructed to achieve the failure detection of suspension spring.Detection result shows that suspension's energy transfer characteristic changes to high scale due to spring stiffness metamorphosis, which is consistent with the conclusion drawn from the detection mechanism analysis to low frequency change, and the method correctly detects suspension failure with 10% stiffness metamorphosis.Therefor, the method has high reliability and good engineering applicability.More>
2013, 13(4): 51-55. doi: 10.19818/j.cnki.1671-1637.2013.04.008
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Fluctuating wind field and wind-induced vibration response of catenary based on AR model
LI Rui-ping, ZHOU Ning, ZHANG Wei-hua, MEI Gui-ming
Abstract: Based on AR model and the structural characteristics of catenary, the fluctuating wind field of catenary related with time and space was established.The fluctuating wind loads acting on the catenary were calculated by the simulated wind speed time series.A three-dimensional finite element model of catenary was established to calculate the modes, static wind deviations and wind-induced vibration responses of catenary, and the spectrums of the displacement responses were analyzed in details.Analysis result indicates that the fluctuating wind field of catenary can be established by using Davenport wind speed spectrum because the vertical wind speed is lower than the along-wind speed.While the lateral average wind and natural wind with the speed of 30m·s-1 acting on the catenary, the maximum lateral displacements of mid-span node of contact wire are 109.11mm and 312.49mm, respectively.The lateral displacement of catenary calculated by the average wind load acting on the catenary decreases by 186.40% compared with the value calculated by the fluctuating wind loads.The lateral displacement of catenary is generated as well as the vertical displacement of catenary under natural wind, the first order vertical and lateral frequencies are 0.973 Hz and 1.384 Hz, respectively, and the windinduced responses of catenary exhibit peak resonant vibration in the zone of the two frequencies.Under natural wind with a speed of 30m·s-1, the stresses of contact wire and support wire caused by the wind loads are about 10.77% and 27.40% of their total stresses, respectively.Therefore, the fluctuating wind loads should be applied to conduct the wind deviation and strength design of catenary.More>
2013, 13(4): 56-62. doi: 10.19818/j.cnki.1671-1637.2013.04.009
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Emission characteristics of diesel bus burning different alternative fuels
TAN Pi-qiang, LI Jie, HU Zhi-yuan, LOU Di-ming
Abstract: The gaseous emissions of diesel bus fueled with pure diesel fuel, gas-to-liquid(GTL)fuel and biodiesel fuel were studied by using OBS-2200 gaseous portable emission measurement system on arterial road, residential road and elevated road. Analysis result shows that the on-road transient mass emission rates of CO, NOx, HC and CO2 have good following performance with the transient change of vehicle speeds. The mass emission rates of gaseous pollutants from the bus burning alternative fuels show a total ascending tendency with increasing vehicle speed. The mass emission rates of HC and CO2 almost linearly increase with ascending vehicle speed, while CO and NOx emissions firstly increase with the speed increasing in low and medium vehicle speed ranges, and then decrease with the speed increasing in high vehicle speed range. Compared to arterial road and residential road, the emission factors of the bus burning alternative fuels on elevated road are the lowest. Compared to pure diesel fuel, the emission factors and mass emission rates of CO and HC from the bus burning biodiesel fuel and GTL fuel decline, and for biodiesel fuel, the decreasing range is greater. The average emissions of CO and HC from the bus burning pure biodiesel fuel on the whole test roads are the lowest. Compared to pure diesel fuel, NOx emissions from the bus burning pure biodiesel fuel are higher on all roads. CO2 emissions of the bus burning pure GTL fuel, GTL fuel with 20% blend ratio and biodiesel fuel with 20% blend ratio are respectively lower than the emission for pure diesel fuel, but CO2 emission of the bus burning pure biodiesel fuel is slightly higher than the emission for pure diesel fuel.More>
2013, 13(4): 63-69. doi: 10.19818/j.cnki.1671-1637.2013.04.010
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Urban public traffic assignment algorithm under influence of transfer behavior
CENG Ying, LI Jun, ZHU Hui
Abstract: Aiming at the work and life modes and the particularities of public traffic networks of big cities in China, the public traffic trip behaviors of residents in Chengdu City were taken as study object, and the generalized public traffic route which could accord with the route choice behavior of passenger was put out.By considering the section impedance and station impedance during the public traffic trip, the impedance function of public traffic route was set up, and the determination method of effective path was proposed.Based on the improved logit model, a route choice model under the influence of transfer behavior was established.The part public traffic network of Chengdu City was taken as an example, the example verification was carried out by using proposed assignment algorithm.Analysis result indicates that when the minimum departure intervals of four designate public traffic lines during peak period are 4, 4, 3, 3min respectively and all the maximum departure intervals during non-peak period are 10min, the minimum and maximum transfer walking times are 0, 6 min respectively.When the maximum impedance and minimum impedance are 71.5, 51.5min respectively, the riding times are 60, 48min respectively, the route choice ratios are 5.53%, 41.98% respectively.When the maximum impedance and minimum impedance are 52.5, 48.5 min respectively, the riding times are 42, 39 min respectively, the route choice ratios are 13.40%, 62.07% respectively.When the transfer behavior is considered, the maximum relative error, the minimum relative error and the average relative error of assignment results and actual values are 16.46%, 11.09%, 14.42% respectively.When the transfer behavior is not considered, the maximum relative error, the minimum relative error and the average relative error are 34.37%, 11.38%, 23.15% respectively.The public traffic assignment result considering transfer behavior is in accord with actual situation.More>
2013, 13(4): 70-78. doi: 10.19818/j.cnki.1671-1637.2013.04.011
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Optimization model of flight time and frequency under operation mode of multi-airports system
WU Gang, XIA Hong-shan, GAO Qiang
Abstract: Aiming at congestion problem at hub airport, the optimization strategy of flight time and frequency for multi-airports system was put out.The transportation demand management theory was used, the minimum trip lost time of passenger was taken as objective function, the passenger wastage rate and the occupancy rate of airline were taken as constraint conditions, and the optimization model of flight time and frequency based on operation mode of multi-airports system was established.According to the ground traffic times of 5airports in multi-airports system and the relation between flight amount and average delay for hub airport, passenger demand in each airport was classified, and the flight time and frequency, the trip lost time of passenger and the distribution modes of aircraft type and amount were calculated by using k-means clustering algorithm.Calculation result shows that under the operatiom mode of multiairports system, passenger demand is classified into 7classes, the flight amount satisfied all passenger demands is 11, and the trip lost time of all passengers is 123 403 min.Under the independent operation mode, passenger demand is classified into 8classes, the flight amount satisfied all passenger demands is 13, and the trip lost time of all passengers is 165 343min.Under the operation mode of multi-airports system, the flight amount satisfied all passenger demands is 11, and the trip lost time of all passengers is 126 119min by using genetic algorithm.More>
2013, 13(4): 79-86. doi: 10.19818/j.cnki.1671-1637.2013.04.012
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Prediction method of highway passenger transportation volume based on exponential smoothing method and Markov model
RUI Hai-tian, WU Qun-qi, YUAN Hua-zhi, FENG Zhong-xiang, ZHU Wen-ying
Abstract: The usual prediction methods of passenger transportation volume were analyzed, a new prediction method of highway passenger transportation volume based on exponential smoothing method and Markov model was put out. Based on the actual value, linear fitting value and quadratic curve fitting value of highway passenger transportation volume, the initial value and smoothing coefficient were calculated by using quadratic curve fitting method. According to the related data of Anhui Province in 2000-2009, the highway passenger transportation volumes in 2010, 2011 were predicted by using exponential smoothing method. Taking -11%, -5%, 0, 5%, 11% as division threshold values, the relative errors of prediction results by using exponential smoothing method were divided into four state intervals, the prediction results of exponential smoothing method were modified by using Markov model, and the prediction results among the proposed method, fuzzy linear regession model and exponential smoothing method were compared. Analysis result shows that by using the proposed method, the prediction results of highway passenger transportation volumes in 2010, 2011 are 1.420 9×1010, 1.571 2×1010 persons, relative errors are 1.195% and 0.492% respectively. By using exponential smoothing method, prediction results are 1.346 8×1010, 1.489 3×1010 persons, relative errors are -3.399% and -4.746% respectively. By using fuzzy linear regession model, prediction results are 1.357 3×1010, 1.532 5×1010 persons, relative errors are -2.647% and -1.983% respectively. The proposed method has higher precision to meet the actical demands.More>
2013, 13(4): 87-93. doi: 10.19818/j.cnki.1671-1637.2013.04.013
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Two-stage dynamic incentive model of synergy and innovation for logistics alliance
TANG Zhi-ying, ZHOU De-su, YE Huai-zhen
Abstract: In order to improve the synergy level and income status of logistics alliance, the income of third party logistics (TPL) was taken as objective function, the incentive compatibility constraint and retained income of member were taken as constraint conditions, and the two-stage dynamic incentive model of synergy and innovation for logistics alliance was established.With the change of substitutable degree for the two tasks such as synergy and innovation, the optimal incentive coefficient and the optimal effort level were calculated, and the fixed incomes of member and the incomes of TPL under the single-stage static incentive and the two-stage dynamic incentive were compared.Analysis result shows that when the retained income of member is 0.6 million yuan and substitutable degree are 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 respectively, the fixed incomes of member are-1.087 7, -1.095 3, -1.084 8, -1.063 0, -1.033 4, -0.999 3 million yuan respectively under the single-stage static incentive and are-1.236 7, -1.106 5, -0.995 1, -0.898 3, -0.816 2, -0.744 7 million yuan under the two-stage dynamic incentive.The incomes of TPL are 1.092 2, 1.100 9, 1.091 1, 1.069 5, 1.039 5, 1.003 2 million yuan respectively under the single-stage static incentive and are 1.245 4, 1.117 2, 1.007 3, 0.911 8, 0.828 1, 0.753 0 million yuan respectively under the two-stage dynamic incentive, the incomes of TPL increase 14.03%, 1.48%, -7.68%, -14.75%, -20.34%, -24.94% respectively.The fixed income of member, the optimal incentive coefficient and the optimal effort level increase with the increase of substitutable degree.When substitutable degree is 0.2, the income of TPL is maximum, and the scheme is optimal.More>
2013, 13(4): 94-101. doi: 10.19818/j.cnki.1671-1637.2013.04.014
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Forecast method of annual senior overhaul amount for EMU
LI Yan, ZHANG Wei-jiao, JIA Zhi-kai
Abstract: To forecast the senior overhaul amounts of all EMUs in arbitrary time period accurately and efficiently, a forecast method of annual senior overhaul amount for EMU was put out.The relative data of existing running rule of EMU on line was taken as initial value, the concrete dates of subsequent senior overhaul and the senior overhaul amounts during the statistical period were calculated, and the total senior overhaul amounts of all EMUs on line were obtained.For the EMUs which were not put into use, the probability calculation method of annual senior overhaul amounts for different overhaul levels were built from macro perspective, and the total overhaul amounts of all EMUs which were not put into use during the statistical period were obtained by using integral statistical method.The total senior overhaul amounts of actual overhaul plan in 2013 and predictive overhaul plan in 2015 were calculated through normalization processing, and correlative comparison and error calculation were carried out.Calculation result shows that when the standard amount of EMU is 670, the day-average mileage on line is from 1 000 km to 3 000 km, and calculation period is 180 d, the relative error of unitary data in 2015 and 2013 is-2.86%, and the relative errors of three-level and four-level overhauls are-0.23% and 9.24% respectively, the errors are within the effective range, and the proposed method is effective.More>
2013, 13(4): 102-107. doi: 10.19818/j.cnki.1671-1637.2013.04.015
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UML-HLA collaborative modeling method and its application in multi-train simulation system
SHANGGUAN Wei, LIU Peng-hui, CAI Bo-gen, SHAO Yong-zhe
Abstract: Aimed at the distributed and interactive properties of complex real-time large system, through a comprehensive comparison of unified modeling language (UML) and high level architecture (HLA) features, a modeling and simulating method of train control system was proposed based on high level architecture with unified modeling language (UML-HLA).On the basis of traditional modeling method, an analysis model of multi-train simulation system was constructed from different perspectives by using UML-HLA modeling method.The model consisted of use case modeling, activity modeling, structural modeling, interactive modeling and state-based modeling, and the high level architecture resource library was constructed.Based on the analysis model, a multi-train simulation system structure was established, and a design model of multi-train simulation system was obtained finally.The functions and performances of multitrain simulation system were validated.Simulation result shows that the modeling method based on UML-HLA has strong interactivity and maneuverability.With the optimization of original thread management mechanism and timer control mechanism, the CPU occupancy of original system reduces from 50% to below 15% by using thread management method, the timer error in the system is below 0.02 ms, and the simulation requirement of train control system is satisfied.More>
2013, 13(4): 108-115. doi: 10.19818/j.cnki.1671-1637.2013.04.016
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Review of traffic signal control methods under over-saturated conditions
LI Yan, ZHAO Zhi-hong, LI Peng-fei, HUANG Shen-sen, CHEN Kuan-min
Abstract: To provide references for traffic control optimization at congested urban road network, various traffic signal control strategies under over-saturated conditions were reviewed and evaluated.Based on the analysis of the characteristics of over-saturated traffic flow, the corresponding optimization principles of traffic signal control under over-saturated conditions were proposed.The traffic control strategies for isolated intersection, coordinated intersections and road network were summarized and evaluated by using VISSIM simulation environment.The control measures of adaptive traffic signal control system with the capability to deal with over-saturated conditions were summarized.Simulation result indicates that traffic signal control strategies under over-saturated conditions should optimize the allocation of road space in the first place.The queue management strategy has better performance on optimizing traffic signal under over-saturated conditions.It is suggested that the strategies like queue ratio maintenance and throughput maximization for critical route should be utilized with real-time traffic information for the optimization at the intersection group or road network level.More>
2013, 13(4): 116-126. doi: 10.19818/j.cnki.1671-1637.2013.04.017
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