交通运输工程学报

Loading performances of pavement with assembled aluminum mats

CAI Liang-cai, ZHOU Shao-hui, XU Wei, CEN Guo-ping, YANG Wen-shan

Abstract: The strength of assembled aluminum mat was detected by four-point bending loading test.Two soil test sections with different strengths were built.Four aluminum honeycombsandwich mats with different thicknesses and strengths were paved on the test sections to simulate different pavements with assembled aluminum mats at expedient airfield.Light and heavy aircraft loads were simulated by using loaded cart.The deformations and ruts of the pavements under different loading times were measured and the control indexes were that the maximum rutting depth reached 30 mm and 20% mats were damaged.Experimental result indicates that the effective moduli of mats 1-4 are 1 616, 1 862, 2 064 and 2 328 MPa respectively.When mats 1-4 are installed over single-layer stabilized soil base and loaded by 75 kN, the vertical deformations of the pavements are respectively 35, 19, 10 and 12mm after 400 loading times, and the relative maximum ruts are respectively 50, 28, 16 and 10 mm after 500 loading times.When mats 1-4 are installed over double-layer stabilized soil base and loaded by 150 kN, thevertical deformation of the pavement with mat 4is 16 mm after 1 000 loading times, the relative maximum ruts of the pavements with mats 3 and 4 are 36 and 24 mm respectively, and the horizontal joints of mats sink obvious.Under the same base condition and loading times, mat 1 made of 3003 aluminum alloy is easier to damage compared with mats 2-4 made of 6A 02 aluminum alloy, and the pavement constructed by mat 1is easier to fail than the others.When mats 1-4 are installed over single-layer stabilized soil base and loaded by 75 kN, the matting pavements can meet the using requirements of light aircrafts.When mat 4 is installed over double-layer stabilized soil base, the matting pavement can meet the using requirements of heavy aircrafts.More>

2015, 15(6): 1-9. doi: 10.19818/j.cnki.1671-1637.2015.06.001

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Permeating-chemical grouting treatment method of sulphate saline soil

WANG Le-fan, WENG Xing-zhong, ZHANG Ren-yi, YAO Zhi-hua, GU Qiang-kang, LI Wan, LI Ye

Abstract: The soil samples with two kinds of dry densities and three kinds of salinities were selected, the adsorption-seepage experiments of pure soils to water and saline soils to barium chloride solution were carried out, the sodium sulfate contents were measured after reaction, and the complete processing lengths of sulphate saline soils were gotten by permeating-chemical grouting treatment method.The influencing factors of complete processing length were analyzed, and the correction factor of complete processing length was computed.Test result shows that the sodium sulfate content of soil sample significantly reduces because of the intelligent use of permeatingchemical grouting treatment method.Under the condition that the dry density is 1.4g·cm^-3 and the permeating-chemical grouting treatment time based on barium chloride solution is about 22 h, when the mass concentrations of sodium sulfate in soil samples are 1%, 2% and 3% respectively, the complete processing lengths of soil samples are 22, 14 and 6cm respectively.Under the condition that the dry density is 1.6g·cm^-3 and the permeating-chemical grouting treatment time based on barium chloride solution is about 70 h, when the mass concentrations of sodiumsulfate in soil samples are 1%, 2% and 3% respectively, the complete processing lengths of soil samples are 10, 6 and 6cm respectively.Therefore, the lower the dry density and saltness of soil sample are, the better the permeating-chemical grouting treatment effect is, and the larger the complete processing length is.The complete processing length is affected by the wetting length, the concentration of barium chloride solution, soil saltness and the increment of water content in soaking section, and the computational correction factor of complete processing length is 0.53.More>

2015, 15(6): 10-16. doi: 10.19818/j.cnki.1671-1637.2015.06.002

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Comparison of wind-vehicle-bridge coupling vibration characteristics for three-line three-tower suspension bridge

LI Yong-le, XU Xin-yu, YAN Nai-jie, DENG Jiang-tao, XIANG Huo-yue

Abstract: Taking the two design schemes(steel-box-truss and steel-truss schemes)of a three-line three-tower suspension bridge as the research object, the three-component coefficients of forces for vehicle and bridge were obtained by the wind tunnel tests of vehicle-bridge system section model.Based on the spatial dynamics model of wind-vehicle-bridge(WVB)system, the dynamic characteristics of bridge and the coupling vibration characteristics of WVB system were analyzed by using the self-developed software BANSYS. Analysis result indicates that the natural frequencies of three-line three-tower suspension bridge are comparatively low.The aerodynamic characteristics of vehicle were greatly affected by track position, and the drag coefficient of windward vehicle for the steel-truss scheme is about 2.2 times that for the steel-box-truss scheme.When wind speed is 0, the dynamic responses of bridge and vehicle increase with the increase of vehicle speed.The displacements of bridge for the steel-truss scheme are bigger than those for the steel-box-truss scheme at the same vehicle speed, which is resulted from the weaker whole stiffness for the steel-truss scheme.When wind speed is considered, the lateral responsesof bridge greatly increase with wind speed increasing.When vehicle is running on the windward side and wind speed increases from 15m·s^-1 to 25m·s^-1, the lateral displacements of bridge for the steel-box-truss and steel-truss schemes enlarge to approximate 2.4 times and 3.8 times respectively, and crosswind is dominant to the lateral responses of bridge.On the whole, the bridge responses for the steel-truss scheme are larger than those for the steel-box-truss scheme under the same wind speed.As for the same scheme, vehicle responses increase with wind speed increasing.When wind speed reaches 25 m·s^-1, the dynamic responses remarkably increase, and the maximum response index increases by 71.6% compared with that at the wind speed of 15m·s^-1.More>

2015, 15(6): 17-25. doi: 10.19818/j.cnki.1671-1637.2015.06.003

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Comparison of selecting methods on rock sample mechanical parameters of rock bank slope

ZHOU Zhi-jun, ZHANG Xing-ming, FENG Jia-jia

Abstract: The axial compression tests of rock samples of typical bank slope in Anchuan Highway were carried out under natural state and water-saturated state, their deformation parameter and shear strength parameters were sampled and selected by the random-fuzzy method, the least square method and the Monte Carlo method, and the stability coefficient of typical bank slope was computed.Calculation result shows that the mean, standard deviation and variation coefficient of deformation parameter obtained by the Monte Carlo method are basically similar to the values obtained by the least square method, and the mean difference is only 0.77%.Relatively, the mean, standard deviation and variation coefficient of deformation parameter obtained by the random-fuzzy method are minimal, and the mean value is 8.60%lower than the value obtained by the least square method.In sampling and valuing of shear strength parameters, the means and variation coefficients of shear strength parameters and the corresponding safety factors of slope from small to large are obtained in turn by the random-fuzzy method, the Monte Carlo method and the least square method, and slope safety factors are 1.243 and 1.521 when the parametersare computed by the random-fuzzy method and the Monte Carlo method respectively.Compared with the Monte Carlo method, the membership function confirmed by the random-fuzzy method considers the weight effect of sample parameter, which can reflect the uncertainty of rock shear strength parameter.The safety factors of rock slope calculated by the random-fuzzy method have more engineering guiding significance.More>

2015, 15(6): 26-34. doi: 10.19818/j.cnki.1671-1637.2015.06.004

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Soil arching effect of low subgrade with pile-net structure under train load

WEI Jing, WEI Ping, YANG Song-lin, ZHANG Dong

Abstract: The dynamic finite element model of low subgrade with pile-net structure was built by using ABAQUS software.The reliability of the model was verified by the comparison of calculated and measured results.The distribution of dynamic stress, the vibration characteristics of pile-soil stress ratio and the height of equal settlement plane under train load were analyzed.Analysis result indicates that the maximum differences of calculated and measured values for dynamic stress and dynamic displacement at different depths of subgrade are 0.56 kPa and 7 μm respectively, the transmission trends of average dynamic stress and dynamic displacement of calculated result are similar to the measured result along the subgrade depth, so the proposed dynamic finite element model is reliable.There exists soil aching effect in subgrade under dynamic load, and the height of soil arching effect is about 1.6 m that is approximately the same with the value under static load.The stress variation ratio under dynamic load in subgrade surfaceis larger than the value in subgrade base, and the stress variation rate in subgrade base is extremely diminutive.The distribution of dynamic stress in subgrade under dynamic load is effected by soil arching effect, and the dynamic stress is partly transferred from soil among piles to pile top, and the phenomenon is most obvious in the cushion of subgrade.After dynamic load, in the center of subgrade, the pile-soil stress ratio of pile top to soil between two piles decreases, and the ratio among four piles increases.The pile-soil stress ratio between two piles is always larger than the value among four piles.The height of equal settlement plane of vertical section with the distance of 1mto the center of subgrade is about 1.55 m.The height of equal settlement plane in vertical section with piles is larger than the value without piles.From subgrade center to subgrade shoulder, the height of equal settlement plane in the same vertical section decreases gradually.After dynamic loading, the height of equal settlement plane in the center of subgrade increases.More>

2015, 15(6): 35-44. doi: 10.19818/j.cnki.1671-1637.2015.06.005

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Vibration properties of locomotive traction gear excited by load fluctuation

WANG Yan, LIU Jian-xin

Abstract: Aiming at the problem of locomotive traction gear vibration excited by load fluctuation, the dynamics equations of locomotive traction gear were built.The vibrational frequency and amplitude of gear were got by using averaging method.The variation tendency of amplitude and the influences of parameter variations on the amplitude after gear vibrating stably were analyzed, and the simulation test of vibration was carried out.Analysis result shows that load torque is a function of vibrational speed.The vibrational frequency is a constant.When creep speeds are0.8, 0.2m·s^-1 respectively, the vibrational frequencies of gear are 335.0 Hz, which is very close to the theoretical value 334.8 Hz.The amplitude decreases to 0 or gradually increase to a stable value according to different situations.When creep speed is 0.8 m·s^-1, the amplitude after gear vibrating stably decreases with the increases of gear meshing stiffness and meshing damping, and increases with the increases of equivalent moment of inertia for small gear and locomotive axle load.Therefore, increasing gear meshing stiffness and meshing damping and decreasing equivalent moment of inertia for small gear and locomotive axle load help to decrease amplitude of gear.More>

2015, 15(6): 45-50. doi: 10.19818/j.cnki.1671-1637.2015.06.006

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Real vehicle test and numerical simulation of flow field in high-speed train bogie cabin

HAN Yun-dong, YAO Song, CHEN Da-wei, LIANG Xi-feng

Abstract: The device for testing the flow field state in bogie cabin of high-speed train was designed. The flow field in bogie cabin was analyzed by numerical simulation method, under the conditions of no crosswind, crosswind speed of 15 m·s^-1 and end plate angles of 30°, 45°and70°. The effect of skirt plate covering on accumulated snow formation was analyzed. Test result shows that the test and simulation results of airflow motion laws are coincident, so the simulation is feasible. Airflow enters into bogie cabin from train bottom and skirt plates of two sides. The flow separation phenomenon happens when airflow flows past end plate. Most airflow comes out from end plate bottom and skirt plate backs of two sides. The speed of airflow past bogie cabin decreases gradually from head car to back car, air inlet area at skirt plate decreases, and air outlet area at skirt plate back increases. Snow grains are taken into bogie cabin by airflow past the cabin bottom and deposit continuously under the effect of flow field of bogie to form accumulated snow. Reasonably setting end plate angle of bogie can decrease the accumulating probability of snow in bogie cabin. Covering skirt plate can not decrease accumulated snow in bogie cabin, and is not recommended.More>

2015, 15(6): 51-60. doi: 10.19818/j.cnki.1671-1637.2015.06.007

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Optimization of aerodynamic noise for vehicle alternator

ZHANG Ya-dong, ZHANG Ji-ye, DONG Da-wei, YAN Bing, HUA Chun-rong

Abstract: The large eddy simulation method and the FW-H acoustic model were adopted to simulate the aerodynamic noise of vehicle alternator.The vector composition method was used to optimize the front-blade distribution angle of alternator.Aiming at low noise, high flow and optimizing spectrum structure to reduce the single-frequency rotational noise, the aerodynamic noise properties of alternator were analyzed.Analysis result shows that the numerical simulation and test results have good consistencies on sound pressure level, main influencing orders and magnitudes of alternator noise.The aerodynamic noise sources of vehicle alternator are front and back blades.The main influencing orders of overall noise are orders 6, 8, 10, 12 and 18, and the main energy centers on 1 120-5 600 Hz.The maximum prediction error of overall noise is 6.97 dB, and the prediction errors of rotational noise on orders 12 and 18 are 2.30 dB and 3.30 dB respectively.After optimizing the front-blade distribution angle of alternator, the maximum decreasing amount of overall noise is 3.10 dB, the average decreasing amount is 2.58 dB, the average decreasing amounts of noise on orders 12 and 18 are 5.80 dB, so the noise reduction effect is remarkable.More>

2015, 15(6): 61-67. doi: 10.19818/j.cnki.1671-1637.2015.06.008

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Laws of high-speed train operation speed acting on line capacity

PAN Deng, MEI Meng, ZHENG Ying-ping

Abstract: The mathematical models of quasi-moving block system and moving block system were used to calculate total vehicle distance, train interval time and line capacity. When brake accelerations were -0.63, -0.75, -0.85 and-0.90 m·s^-2 respectively, the simulation experiments were carried out to analyze the laws of high-speed train operation speed acting on line capacity.Analysis result shows that safe headway is proportional to initial speed when train decreases speed to stop.Train interval time and line capacity are closely related to safe headway, train operation speed and initial parameter values.The minimum of train interval time and the maximum of line capacity exist accordingly.The smaller braking acceleration is, the smaller train interval is, and the greater line capacity is.Train interval time can be controlled in 3 min, and line capacity can reach over 1 000 trains a day.Train interval time of quasi-moving block system is longer than that of moving block system, and its line capacity is less than that of moving block system.Considering the feasibility of engineering application makes the line capacity gap between quasi-moving block system and moving block system to further expand.More>

2015, 15(6): 68-74. doi: 10.19818/j.cnki.1671-1637.2015.06.009

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Scheduling optimization of acceptable flight formation based on improved GH-SOM

MENG Ling-hang, XU Xiao-hao

Abstract: Aiming at the scheduling optimization problem of acceptable flight formation, the maximum equivalent range constraint and the maximum allowable delay time constraint were considered, and the statistical decision boundaries of acceptable formation pattern were derived.The formation scheduling optimization problem was transformed into the optimal hierarchical clustering problem, and an improved growing hierarchical self-organizing map(GH-SOM)neural network was used to realize the scheduling clustering recursive refinement of acceptable flight formation.Simulation result shows that compared with the empirical boundaries, the recognition quantity based on the statistical decision boundaries of acceptable formation increases by 92.14%, the mean flat rate and mean time synchronization deviation decrease by 25.00% and 26.23% respectively, and the standard deviations of flat rate and time synchronization deviation decrease by 12.50% and 18.75% respectively.Compared with self-organizing map(SOM)and standard GH-SOM, the recognition quantities based on the improved GH-SOM increase by 303.49% and 162.87% respectively, the mean flat rates decrease by 34.25% and 22.58% respectively, the mean time synchronization deviations decrease by 47.06% and 36.62% respectively, the standarddeviations of flat rates decrease by 45.10% and 6.67% respectively, and the standard deviations of time synchronization deviations decrease by 46.94% and 3.70% respectively.Therefore the statistical decision boundaries of acceptable formation pattern and the improved GH-SOM proposed in this paper are effective.More>

2015, 15(6): 75-82. doi: 10.19818/j.cnki.1671-1637.2015.06.010

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Speed estimation model during lane-changing decision

WANG Chang, FU Rui, ZHANG Qiong

Abstract: In order to research the driver's estimation characteristic for rear-vehicle speed during lane-changing decision, small passenger car was used as test platform and established by using microwave radar, vehicle CAN-bus data logger, audio-video monitoring system.15 drivers were recruited, and the estimation test of rear-vehicle speed was carried out in a normal highway.The speeds of test vehicle were set as 60, 70, 80, 90km·h^-1 separately, and 1 625 sets of data were obtained finally.The impact characteristics of relative speed, rear-vehicle speed, and relative distance on driver's speed estimation behavior were analyzed by using significance analysis method.A driver's speed estimation model was established by using multiple linear regression theory, and the model was examined.Analysis result shows that 60% of absolute values of speed estimate errors are no more than 10km·h^-1, and the driver's speed estimation error follows a normal distribution.Driver's speed estimation error decreases with the increase of relative speed and rear-vehicle speed, when the relative speed or rear-vehicle speed is lower, rear-vehicle speed is overestimated, and when the relative speed or rear-vehicle's speed is higher, rear-vehicle speed is underestimated.When the relative distance of vehicles increase, the driver's speed estimationerror change very small.However, when the relative distance is smaller, rear-vehicle speed is overestimated by driver.The average estimation errors of speed estimation model is-0.56km·h^-1, so the model is feasible.More>

2015, 15(6): 83-91. doi: 10.19818/j.cnki.1671-1637.2015.06.011

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Repair method of traffic flow malfunction data based on temporal-spatial model

LU Hua-pu, SUN Zhi-yuan, QU Wen-cong

Abstract: In order to improve the accuracy of traffic flow data, the characteristics of temporal correlation, spatial correlation and historical correlation of traffic flow big data were considered, and a basic traffic flow temporal-spatial model was built.To ensure the accuracy and speed of data processing, the simplification and calibration of temporal-spatial model were realized.The temporal-spatial model was simplified and abstracted into a bi-level programming model.The operation speed was optimized in the upper level model by controlling the number of temporalspatial correlation coefficients, and the calculation accuracy was optimized in the lower level model by controlling the error.Based on the data-driven method, the bi-level programming model was solved, and the calibration of temporal-spatial model was completed.Based on the proposed temporal-spatial model, a repair method of traffic flow malfunction data was presented.Taking a road section in Beijing City as example, the validity and feasibility of proposed repair method were verified.Verification result indicates that the precisions of repair methods of traffic flow malfunction data based on historical trend, spatial correlation and time series are 79.65%, 85.16%, 89.84% respectively, however, the precision of proposed method based on the temporal-spatial model is 90.91%, that is relatively higher, the characteristics of traffic flow big data can be accurately described by the proposed repair method.More>

2015, 15(6): 92-100. doi: 10.19818/j.cnki.1671-1637.2015.06.012

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Traffic signal control optimization model of over-saturated intersection based on dynamic programming

LI Rui-min, TANG Jin

Abstract: In order to satisfy the signal control demand of over-saturated intersection, an optimization model was established by using dynamic programming theory.The stages, state variables, and decision variables were redefined.The state transition equations of average queue length and controller were built.The objective functions and constraints based on different intersection saturated states were determined.The optimization framework of the model was proposed.The control objective of unsaturated states was designed as the minimum delay, and the control objectives of saturated and over-saturated states were designed as the maximum capacity.Through iteration operations, retaining or changing the current phase was decided, and the signal timing program of next stage was adjusted by the real-time feedback of control effects.Taking an intersection of Qinhuangdao City as an example, the traffic flows of unsaturated, saturated and over-saturated states were obtained based on the actual collected data.The signal timing program was obtained by using the dynamic programming model, and compared with the signal timing program obtained by using TRANSYT method.Analysis result indicates that for the unsaturated state, the average delay, saturation, and average queue length obtained by the proposed model are 49.3s, 0.76, 13.7veh respectively, and the corresponding values obtained by TRANSYT method are 52.0s, 0.78, 14.4veh, respectively.For over-saturated state, the saturation and average delay obtained by the proposed model are 0.85 and 78.5 srespectively, and the corresponding values obtained by TRANSYT method are 0.86 and 82.5 srespectively, however, the corresponding average queue length is 27.3 veh that is slight better than the optimization value 27.6veh.The control effect of saturated state is similar to over-saturated state.Obviously, the proposed model based on dynamic programming can effectively reduce the intersection saturation and the average delay of vehicle for each import of each phase.More>

2015, 15(6): 101-109. doi: 10.19818/j.cnki.1671-1637.2015.06.013

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Locating algorithm of urban variable message signs

SI Bing-feng, CHEN Bo-yang, JIANG Ming-qing, YANG Xiao-bao

Abstract: Not only the static factors including road grade, traffic flow, and road operation state, but also the dynamic factor of information attenuation property were considered, a locating algorithm of urban variable message sign(VMS)considering the properties of road sections was proposed.In view of 4main road properties closely related to the traffic guidance, including road grade, traffic flow, layout effect, and information superposition, road sections were scanned in multi-level.The traversal ranges of traffic flow and layout effect of road section were introduced into the algorithm.The importance degrees of different properties were controlled by adjusting the two parameters.The algorithm was verified by using a local road network of Beijing City.Verification result shows that when the two parameters change from 0.3 to 0.6, the layout orders of different road sections change.The road sections with high grades have layout priority, even if the traffic flow is small.Based on the same interval of traffic flow, the roads with better layout effect are selected to locating VMS preferentially.In practice, if more VMSs are requested to layout on high-grade road sections, the layout order can be adjusted by adjusting the parameters.More>

2015, 15(6): 110-117. doi: 10.19818/j.cnki.1671-1637.2015.06.014

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Vehicle detection and tracking algorithm based on monocular and binocular vision fusion

CAI Ying-feng, WANG Hai, CHEN Xiao-bo, JIANG Hao-bin

Abstract: The monocular and binocular vision fusion based vehicle detection and Kalman filter based vehicle tracking algorithm was proposed.The 2D deep belief network based vehicle detector was designed.In road images, the monocular vision was used to generate probably existing area of vehicle that composes vehicle candidate set processed by the binocular vision.The binocular vision was used to further eliminate error detection and obtain vehicle position information.The Kalman filter was used to track detected vehicles in 2D image coordinate system and 3D world coordinate system.Test result shows that the detection rate of the algorithm is 99.0%, the error detection rate is 1.3×10^-4%, and the detection time is 57 ms.So the detection rate is high, the error detection rate is low, and the detection time is short.Compared to the monocular and binocular vision weak fusion algorithm, the monocular vision algorithm and the binocular vision algorithm, the proposed vehicle detection and tracking algorithm has both the advantage of binocular vision with high detection rate and the advantage of monocular vision with short detection time.More>

2015, 15(6): 118-126. doi: 10.19818/j.cnki.1671-1637.2015.06.015

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2015 Vol. 15, No. 6

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