交通运输工程学报

Mechanical responses of thin-layer asphalt concrete utilized in bridge deck pavement

ZHAO Yan-jing, FANG Tao, NI Fu-jian, CAO Jin

Abstract: Thin-layer asphalt concrete was paved on cement concrete bridge, finite element analysis software ABAQUS was utilized to build the 3D models of box girder bridge and flanged girder bridge respectively, and the mechanical responses of pavementes with different thicknesses under traffic and thermal loads were analyzed.In addition, the effect of pavement gravity on bridge structure was studied.The result indicates that the maximum vertical shear stresses in box girder bridge and flanged girder bridge increase by about 72% and 40% respectively under vehicle load when pavement thickness increases from 4 cm to 12 cm.Thus, the possibility of the rutting occurrence decreases because of the application of thin-layer pavement.The influence of pavement thickness on the tensile stress is not obvious under thermal load, and each mechanical index is at the similar level.Under the gravity of pavement, the maximum Mises stress and principle tensile stress in box girder bridge respectively decrease by 19.62% and 17.70% by decreasing pavement thickness from 12 cm to 4 cm.At the same condition, the stress levels in flanged girder bridge respectively decrease by 13.79% and 10.16%, and the stress distribution in bridge structure is meliorated.Therefore, thin-layer asphalt concrete is feasible to be utilized in bridge deck pavement when environment condition and material performance are considered in actual engineering.More>

2010, 10(3): 1-9. doi: 10.19818/j.cnki.1671-1637.2010.03.001

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Safety design and evaluation method of long-steep downgrade sections for expressway

YANG Hong-zhi, HU Qing-yi, XU Jin-liang

Abstract: The spatial and temporal distribution of traffic accidents and the distribution of vehicle types were counted for long-steep downgrade sections of expressway.The conditions of tested road sections and the causes of traffic accidents were analyzed.The running speeds of cars on expressway were surveyed by section observation method, and their running speed prediction model was formulated.The temperatures of brake drums for trucks were measured by DHS-130XL infrared observing instrument, and their temperature predict model was set up.The definition of long-steep downgrade was proposed.The indices of average longitudinal slope were determined, and the reasonable average longitudinal slope lengths of long-steep downgrade sections were determined.The safety design and evaluation method of long-steep downgrade were put forward.Analysis result shows that for long-steep downgrade sections, the main reasons of traffic accidents are overspeed and brake failure, the running speed can be used as the safety evaluation index for cars, while slope length and the temperature of brake drum for trucks.The temperatures of brake drum for security slope length, general safety slope length and maximum limit slope length are 200 ℃, 220 ℃ and 260 ℃ respectively.The amount of traffic accidents reduces by 42.3% and casualties reduces by 76.2% after setting some safe improvement measures at the sections, so the measures are effective.More>

2010, 10(3): 10-16. doi: 10.19818/j.cnki.1671-1637.2010.03.002

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Uniformity evaluation standard of subgrade based on reliability

LI Yue-jun, WU Ya-zhong, LI Liang

Abstract: A new uniformity evaluation method of subgrade was proposed based on reliability.A 2D finite element model was established to compute the reliabilities of asphalt pavements with different moduli and variation coefficients by using Monte Carlo Method.A division basis of the reliabilities was set down based on the research on the influence of the coefficients on pavement reliabilities.Computation result shows that the coefficients are 0.05 and 0.10 as the critical values of reliabilities are 95% and 90% for expressway and first class highway.The coefficients are 0.05 and 0.15 as the critical values are 90% and 85% for second class highway.The coefficients are 0.15 and 0.25 as the critical values are 85% and 80% for third and fourth class highways.Subgrade uniformities are divided into three grades when 90% and 95%, 85% and 90%, 80% and 85% are taken as the evaluation standards of subgrade uniformities for different highways.More>

2010, 10(3): 17-22. doi: 10.19818/j.cnki.1671-1637.2010.03.003

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Stability analysis of rock slope based on cusp catastrophe theory

WANG Si-zhang, SHE Xue-sen, LI Yi, MU Peng

Abstract: A mechanical model for the assessment of rock slope stability was built, the criterions of the mechanical conditions resulting in the failure and instability of rock slope were inferred, the stability of rock slope was analyzed by using cusp catastrophe theory and limit equilibrium stability method applied in rigid bodies, and the latter deficiency was studied.With rigid limit equilibrium method, the stability coefficient of rock slope is 0.989, and is less than 1, which means that the slope is unstable.With cusp catastrophe theory, the rigidity ratio of the slope is 1.120, and is greater than 0.806 that is the reciprocal of water softening ratio, which means that the slope is stable.In fact, the slope is stable in excavation process, so cusp catastrophe theory may be used to analyze the stability of rock slope with complex factors.More>

2010, 10(3): 23-27. doi: 10.19818/j.cnki.1671-1637.2010.03.004

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Technical framework of monitoring and evaluating highway water destruction based on remote sensing and GIS

ZHANG Yong, GAO Ke-chang

Abstract: A model that was used to automatically extract the information of landslide and debris flow from ALOS image was constructed based on the demand analysis of remote sensing image.An automatic system and a technical workflow were built to evaluate highway water destruction by combining remote sensing and GIS software.A typical area in Beichuan County of Sichuan Province was selected as the study area to automatically monitor and evaluate highway water destruction after "5.12" earthquake.The result of test was compared with the result from higher resolution satellite images through visual interpretation.The length error of water-ruined road from the two methods is less than 10%.The relatively applicable satellite resources are those images who are multi-spectrum and whose spatial resolution is between 2 m to 10 m for monitoring highway water destruction whose scale is over 400 m².More>

2010, 10(3): 28-34. doi: 10.19818/j.cnki.1671-1637.2010.03.005

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Effect of double-thin-wall distance on seismic response of continuous rigid frame bridge

SHI Xiong-wei, LIU Hai-peng, ZHOU Yong-jun, HU Zhao-tong, YUAN Zhuo-ya

Abstract: In order to study the effect of pier's layout on the seisimic response of continuous rigid frame bridge, a curved rigid frame bridge was taken as an example, the natural frequencies of the bridge under five double-thin-wall distances were analyzed by finite element procedure, and artificial earthquake wave was employed to compute the elastic seismic response of the bridge.The result shows that when double-thin-wall distance lies between 1/20 and 1/25 of main span, the change of fundamental frequency is not more than 5%, and the seismic responses of the moments of girder and pier and the displacement of the superstructure are not more than 12%, which indicates that the natural frequencies and the seismic response of the structure are not sensitive to double-thin-wall distance.So during the period of primary design, the effect of double-thin-wall distance on the dynamic performance of continuous rigid frame bridge can be neglected if the bridge has ordinary double-thin-wall distance.More>

2010, 10(3): 35-40. doi: 10.19818/j.cnki.1671-1637.2010.03.006

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Motion control model of supercavitating vehicle considering time-delay effect of supercavitation

LUO Kai, LI Dai-jin, DANG Jian-jun, WANG Yu-cai, ZHANG Yu-wen

Abstract: Based on the cavitation theory of unattached expansion, the time-delay effect of supercavitation was considered, the vector from the empennage center of maneuverable supercavitating vehicle to supercavitation center in accompanying reference frame was established, and a motion control model of the vehicle was presented, which could describe the maneuverable motion property of the vehicle.Convenient for practical application, the model was simplified to straight-and-level flight without roll based on investigating the motion characteristics of the vehicle.The model is close and applied.It adequately considers the time-delay effect of supercavitation, accurately describes the motion characteristics of the vehicle at cruise phase and is the base of designing the motion control system of the vehicle.More>

2010, 10(3): 41-45. doi: 10.19818/j.cnki.1671-1637.2010.03.007

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Effect of longitudinal stiffness of traction rod on car body elastic vibration for high-speed passenger car

HUANG Cai-hong, CENG Jing, LUO Ren, WU Hui-chao

Abstract: In order to reduce car body elastic vibration, the vibration transmission paths exciting car body elastic vibration were analyzed.A finite element model of car body for high-speed passenger car was established, a rigid-flexible coupling system dynamics model of passenger car was established by using FEMBS module of multi-body dynamics software SIMPACK, and the effect of longitudinal stiffness of traction rod on car body elastic vibration was researched.Considering traction rod's basic hauling and braking functions, traction rod with variable stiffness was used to suppress car body elastic vibration.Simulation result shows that the longitudinal stiffness of traction rod doesn't affect car body rigid vibration but elastic vibration.Wheel imbalance leads to serious car body elastic vibration, which often occurs at low speed.Traction rod with variable stiffness can meet the hauling and braking functions, and can reduce the vertical elastic vibration and longitudinal vibration of car body effectively, but can't affect its lateral vibration.More>

2010, 10(3): 46-51. doi: 10.19818/j.cnki.1671-1637.2010.03.008

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Characteristic of dynamic interaction between wheel and rail due to wheel tread flat on heavy haul railway

LIU Jian-xin, YI Ming-hui, WANG Kai-yun

Abstract: The excitation effects of new and old wheel tread flats for heavy haul vehicle were considered, and the responses of wheel/rail forces, the displacements and accelerations of track in time and frequency domains were studied by simulation.The result shows that under the action of the new flat, there are a high-frequency wheel/rail vertical force and a low-frequency wheel/rail vertical force, and the frequencies of track displacements are low.Due to the old flat, there is a high-frequency wheel/rail vertical force only, the displacements of track are little, and the high-frequency displacement amplitude is lager than low-frequency displacement amplitude.Furthermore, the frequencies of vertical accelerations of rail due to both of the flats are high, the acceleration of the ballast due to the new flat is larger than that due to the old flat, and both of the characteristics of sleeper accelerations are similar.More>

2010, 10(3): 52-56. doi: 10.19818/j.cnki.1671-1637.2010.03.009

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Experimental method of gasoline evaporation loss in refueling process of vehicle

HE Ren, CAI Jin-rong, HE Jun, Liang Lin-lin

Abstract: In order to measure the gasoline vapor emission quality in refueling process, the experimental methods of gasoline evaporation loss were studied, and a collection equipment was designed.The basic components and working principle of the equipment were introduced.Under the condition that average temperature was 25 ℃ and RVP (Reid vapor pressure) was 62 kPa, three experiments were operated.The result shows that for the detection system with carbon canister but without ORVR (on-board refueling vapor recovery) , refueling emission reduces by 15.7%. However, while installing carbon canister and ORVR, refueling emission reduces by 93.9%.More>

2010, 10(3): 57-61. doi: 10.19818/j.cnki.1671-1637.2010.03.010

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Determined models of optimal length for urban rail transit line

LUO Xiao-qiang, CHEN Kuan-min

Abstract: The investment and benefit of urban rail transit line were considered comprehensively, the optimization method of urban rail transit line length was proposed from economic view, and the relationships among length, construction costs, vehicle purchasing costs, operating and maintenance costs, the saving value of travel time and the ticket income of urban rail transit were analyzed.The determined models of optimal length for urban rail transit line were established with maximizing relative net benefit in accordance with the linear and ring structures of urban rail transit lines, and the models were evidenced by empirical data.Analysis result shows that the optimal lengths for urban rail transit lines are between 14.5 km and 37.0 km with the usual intensities of passenger flow, and the optimal lengths are inversely proportional to the intensities of passenger flow.The conclusion is much close with the empirical control objective in urban rail transit project construction standards (JB 104—2008), so the models are valid.More>

2010, 10(3): 62-66. doi: 10.19818/j.cnki.1671-1637.2010.03.011

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Determined method of subway footway width based on queuing theory

JIANG Yang-sheng, HU Lu, LU Guo

Abstract: Subway footway and passenger flux were described as a queuing system at rush hours, a queuing optimization model was built based on the analysis of parameter characteristics, and a new approach for determining subway footway width was developed by combining the level of service for passengers with the calculation of subway footway capacity.A simulation model was proposed to testify the theoretical model above, which was capable of simulating the queuing system with any arrival process and any distribution of service time.Comparison result shows that the results of queuing optimization model and stochastic simulation at the lowest level of service are both close to the values of existing design norm, but with the improvement of service level, the values calculated by the former two methods show a remarkable trend of simultaneous growth, while those derived from the existing design norm show a level trend.More>

2010, 10(3): 67-71. doi: 10.19818/j.cnki.1671-1637.2010.03.012

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Layout optimizing model of alternative interchange in highway network

CHEN Da-wei, XU Zhong, LI Xu-hong

Abstract: The common principles of layout planning for alternative interchange were analyzed, and a bi-level planning model was proposed to describe the layout optimization of alternative interchange from the perspectives of transportation planners and users.The upper-level model was from the perspective of transportation planners, its target was system optimization by optimizing interchange layout, and it was solved by genetic algorithm.The lower-level model was from the perspective of users, the traveling characteristics of users were described, the rational routes of users were arranged by adopting stochastic user equilibrium model, and the lower-level model was solved by the method of successive averages.Case computation result shows that the optimal solution is solved in 19 iterations, the model has high efficiency, and is feasible.More>

2010, 10(3): 72-76. doi: 10.19818/j.cnki.1671-1637.2010.03.013

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Selection model of trip modes for rural population

FENG Zhong-xiang, LIU Hao-xue, ZHANG Jing-feng

Abstract: Referring to the 1 249 survey data of rural population in 12 provinces of China, the influence factors of trip selection modes were analyzed.Based on the theory of disaggregate discrete choice and its modelling method, 6 daily trip modes including walk, bicycle, motorcycle, agricultural truck, bus and private car were selected as the alternatives of trip modes, the characteristic variables affecting mode choice and the method getting their values were determined, and a multinomial logit(MNL)model was developed.Another 400 trip data of rural population were selected to testify the model' s validity.The result shows that the maximal absolute error between statistical data and computational values by MNL is 4.0%, so MNL has high accuracy.More>

2010, 10(3): 77-83. doi: 10.19818/j.cnki.1671-1637.2010.03.014

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Running characteristics of equivalent people group at urban road intersection

LI Ai-zeng, WANG Wei, LI Wen-quan

Abstract: Based on the running characteristics of non-motorized vehicles and pedestrians when they passed through intersection, equivalent people group was defined to describe its influence on vehicles.Considering sample stability, sample number and application convenience, the analysis period of 15 min was adopted, and equivalent people groups' data at peak hours were investigated.The correlation models among equivalent people number, average group time headway and group number were got by means of regression analysis.Analysis result indicates that the group time headway of equivalent people group is shifted negative exponential distribution, the average group time headway decreases with the increase of equivalent people number, and the group number firstly increases and then decreases with the increase of equivalent people number.More>

2010, 10(3): 84-89. doi: 10.19818/j.cnki.1671-1637.2010.03.015

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Operating speed models for trucks at expressway tunnel sections

FANG Jing, WANG Shuang-jie, ZHU Zhan-dong, ZHOU Rong-gui

Abstract: In order to identify the characteristic points and operating speeds for trucks at expressway tunnel sections, the operating speed characteristics at tunnel sections were analyzed.According to car following tests, the driving behaviors and speed changes of trucks in varied length tunnels were studied, and the observation points at tunnel sections were identified.After speed observation, the characteristic points at tunnel sections were verified, the operating speed models for the characteristic points were achieved, and the validities of the models were verified.Analysis result shows that middle tunnel and short tunnel have little impacts on truck speed.200 m before tunnel entrance, entrance point and 100 m after exit are determined as three characteristic points of operating speed for long tunnel, the relative errors of the models are within 10%, so the models are valid.More>

2010, 10(3): 90-94. doi: 10.19818/j.cnki.1671-1637.2010.03.016

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Integrated optimization on both vehicle filling and routing for van truck transportation

JIN Zhi-hong, YU Bo, HOU Li-xiao

Abstract: By means of introducing the residual space and its correlative operations, a mixed integer programming model was proposed based on the integrated optimization on both vehicle filling problem (VFP) and vehicle routing problem (VRP) for van truck.A new interactive algorithm was designed which combined C-W saving algorithm with packing algorithm based on residual space, and simulation tests were compared.Test result shows that the total objective function of the integrated optimization increases by 40.8% and 18.2% compared with two kinds of separate optimization instances, which preferentially consider VFP and VRP respectively, so the integrated optimized model and its algonithm are valid.More>

2010, 10(3): 95-100. doi: 10.19818/j.cnki.1671-1637.2010.03.017

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Two-part pricing model of container liner based on gross mass of individual container

YIN Ming, SHENG Zi-ning, DING Yi-zhong, WANG Xue-feng

Abstract: To resolve the irrational use of carrying capacity and the low efficiency of slot employment resulted from unreasonable pricing system in container liner shipping, a nonlinear pricing revenue optimization model was conducted based on classical two-part pricing theory and in virtue of relevant statistics characteristics obtained from sampling analysis.A series of mathematical experiments were carried out through MATLAB programming, and certain optimization conclusions with factors concerned under different laws were drawn.Analysis result indicates that under certain conditions, the revenue of container liner shipping enterprise can increase by 20%, and the rate of slot employment can reach to 100%, so the model is valid.More>

2010, 10(3): 101-109. doi: 10.19818/j.cnki.1671-1637.2010.03.018

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Traffic assignment method based on dynamic fuzzy control and fuzzy decision making

ZHANG Lin, DU Wen, SONG Jun-ji, XIANG Hong-yan

Abstract: In order to improve the operational efficiency of whole traffic network, a nonlinear programming model was established, and the corresponding nonlinear fuzzy programming model was further obtained by using dynamic fuzzy control methods.According to the magnitudes and directions of adjacent intersection traffic flows, intersection signal dynamic phases were reasonably allocated by using different elastic signal periods and maximum membership degree principle.Based on the observation path of driver, the minimum detection impedance path was obtained, the impedance was compared with the path impedances of intelligent transportation system, and the greatest satisfaction path was chosen.Analysis result indicates that the traffic assignment based on dynamic fuzzy control and fuzzy decision making method is consistent with the shortest path method, and the control effectiveness of signal intersection increases by 50% or more based on fuzzy optimal control, dynamic fuzzy control and fuzzy decision making method can accurately reflect human behavior, and is an effective measurement for signal intersection control.More>

2010, 10(3): 110-117. doi: 10.19818/j.cnki.1671-1637.2010.03.019

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Reconstruction method of line parameters in traffic accident scene plane by photogrammetry

LU Guang-quan, HU Nan, LI Yi-bing

Abstract: Based on the theory of 3D reconstruction of space lines and through 3D reconstruction of scene space lines under photogrammetry system, the drawing plane of traffic accident scene was constructed by the least median of squares method, and the scene space lines' transformations from photogrammetry system space to road traffic accident drawing plane were completed.The examination and reconstruction of lines' parameters in road traffic accident scene plane were realized.Test was done to reconstruct drawing plane, middle line, right and left edge lines in the reference frame of photogrammetry system.The projective equations of middle line, right and left edge lines in drawing plane were calculated, and the lines were drawn in drawing plane.Test result indicates that the differences of angles among edge lines, middle line and x axis are less than 0.1°, and edge lines and middle line are almost parallel, so the measurement precision is exact.More>

2010, 10(3): 118-121. doi: 10.19818/j.cnki.1671-1637.2010.03.020

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Multilevel decision method of ship's tropical cyclone avoidance route using multisource track forecast

ZHANG Wen-jun, WEI Shu-yi, LI Qiang, LIU Da-gang, LIU Zheng-jiang

Abstract: In order to reduce the unsafe affection on ship's tropical cyclone (TC) avoidance caused by the errors of TC track forecasts, the present situations of techniques used in ship's TC avoidance and TC track forecast were introduced, and the purport using multisource track forecast was analyzed.In the basis of introducing the application integrating multisource prediction results from observatories, a specific method using the technique of multisource data fusion and a multilevel decision diagram for ship's avoiding TC were put forward.Study result shows that TC avoidance route decided by using multisource forecast results and multilevel decision will enable decision makers to consider all the results from different observatories and more possible TC tracks, so as to reduce possible danger and loss farthest, and ensure the safeties of ships and mariners.More>

2010, 10(3): 122-126. doi: 10.19818/j.cnki.1671-1637.2010.03.021

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2010 Vol. 10, No. 3

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