交通运输工程学报

Influenced of train speed on dynamic characteristics of ballastless track subgrade

Qiu Yan-jun, Zhang Xiao-jing, Wei Yong-xing

Abstract: In order to analyze the influence of train speed on the dynamic characteristics of ballastless track subgrade, a 3-D layer finite element model of the subgrade was establisbed by using layer system theory and finite element method, the different speed influences of train load on the vertical acceleration, vertical displacement, dynamic stress and its transverse distribution characteristics of the subgrade surface layer were considered, and the mechanical behaviors of the subgrade under train load were studied.It is observed that the vertical acceleration is obviously affected by train load speed, and the acceleration increases with train load speed raising; the dynamic displacement is little influenced by train load speed, and its change value is less than 0.05 mm when the speed increased by 20 km·h^-1; the dynamic stress presents a fluctuate trend with train load speed increasing.The result is similar to actual measure result, and approves the correctness of the model.More>

2007, 7(2): 1-5.

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Influence of primary longitudinal position clearance on lateral dynamics of vehicle with MRF coupled wheelsets

Ni Ping-tao, Wang Kai-wen, Chen Jian

Abstract: In order to reasonably control the position clearance of vehicle wheelsets, improve the lateral dynamics performances of vehicle with magneto-rheological fluid (MRF) coupled wheelsets at high speed, a spatial dynamics model of vehicle was established, and the longitudinal position clearance influence of vehicle wheelsets on the critical velocity and curve passing performances of vehicle were analyzed.Analysis result shows that the clearance increase can make vehicle critical velocity descend sharply, make the lateral displacement and attack angle of wheelsets, the lateral force of wheel/rail and lateral acceleration of carbody largen rapidly; vehicle has higher critical velocity and better curve passing performances only in the condition of small clearance.More>

2007, 7(2): 6-9.

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Mixed marshalling influence of light vehicles and heavy vehicles on train stability

Chi Mao-ru, Zhang Wei-hua, Ceng Jing, Dai Huan-yun, Wu Ping-bo

Abstract: In order to study the stability of mixed marshalling train with light vehicles and heavy vehicles, a dynamics model of mixed marshalling train was set up.Circular-variable method was utilized to resolve the difficult problem of train freedom degrees blast, blocking modelling method was utilized to resolve the difficult problem of mixed marshalling modelling, and the coupling relation among the longitudinal, lateral and vertical performances of train was considered.The model was utilized to analyze train stability under all kinds of mixed marshalling cases about light tank cars and heavy tank cars.It is pointed that the stability of light tank cars placed into the front and back of train is worse than that of light tank cars placed into the middle of train.So in order to increase the stability of mixed marshalling train, the light tank cars should be placed into the middle of train.More>

2007, 7(2): 10-13.

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Dynamic simulation and plant test for locomotive and rolling stock

Huang Li-xiang, Zhang Wei-hua, Ma Qi-wen, Chen Liang-qi

Abstract: The importance of dynamic simulation techniques including prototype simulation, computer simulation and hybrid simulation in the development of locomotive and rolling stock were analyzed, and the relationship among simulation techniques, simulation objects and study contents were put forward.Through the use of computer simulation for the object analysis of locomotive and rolling stock, the structures and suspension parameters could be optimized.Prototype simulation and hybrid simulation were adopted to investigate the operating behaviours of vehicle parts.Full size testbed was utilized to simulate and determine vehicle running behaviour.The procedures of computer simulation, the similarity laws of prototype simulation and the implementation measures of hybrid simulation were introduced.The methods and classifications of railway vehicle testbed tests were discussed, and the application of testbeds for railway vehicles was described.The main technical specifications and functions of the roller testbed and the parameters measuring plant developed by traction power state key laboratory were introduced.More>

2007, 7(2): 14-18.

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Variable period updating algorithm of multiradar and ADS data fusion

Bai Song-hao

Abstract: In order to improve the surveillance performance of air traffic control system, the differences in contents and characters between ADS data and radar data were analyzed, the data mapping relation of multiradar target and ADS target was established, a new data fusion process model of multiradar data and ADS data was put forward, and a variable period updating algorithm was applied to determine the power factors of radar and ADS tracks in data fusion based on the position reporting period change of ADS information.Applied result shows that the algorithm can enhance information fusion depth and valid information utilization, ensure the whole accuracy of ATC surveillance when ADS data has a high updating rate, keep the smooth of target tracks when ADS report rate decreases, and decrease the influence of radar errors on surveillance system.It is an effective method for processing surveillance data in air traffic control system.More>

2007, 7(2): 19-23.

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Numerical value integral improvement algorithm of aircraft take-off running distance

Song Hua-yu, Cai Liang-cai, Zheng Ru-hai

Abstract: The numerical value integral algorithm of aircraft take-off running distance was studied by numerical value calculation theory, and an improvement algorithm was put up.The calculation method of engine instantaneous thrust and take-off aerodynamics data was improved by interpolation method.The liftoff speed was calculated by iteration method.Aircraft take-off running distance calculation was programmed based on the improved algorithm.In order to test the improved algorithm, the take-off running distances of 5 aircrafts were computed when their engine thrust curves were offered.The average error of the former algorithm is 55.6 m, while the one of the improved program is 23.4 m.Furthermore, 12 kinds of take-off running distances of a certain aircraft were computed when its engine thrust curve wasn't offered.The average relative error between computation result and actual running distances is 2.9%.The results indicate that the computation precision of the improved algorithm is higher than the former algorithm.More>

2007, 7(2): 24-28.

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Design method of asphalt concrete pavement for military airfield

Weng Xing-zhong, Sun Jian-bin, Yang Chuan-xi

Abstract: In order to reasonably design the asphalt concrete pavement of military airfield, design airplane was regarded as calculating load, the conversion relations of traffic volumes between different airplanes were analyzed by using fatigue equivalent principle, the tensile stresses of surface, base, subbase and the shear stress of surface were regarded as the structure design indices, according to the characteristics of pavement load, pavement material and pavement damage, airfield pavement was designed by using elastic layered theory.When the mix traffic consisted of H-6, MD-82 and B727-100, H-6 and MD-82 were used as the design load to design asphalt pavement separately, and the structure thicknesses of pavement were computed by using the program of Pave 2000.Computation result shows that the design thickness of subbase is 34 cm with H-6, it is 33 cm with MD-82, their relative error is only 3.03%, which indicates that the design method is correct.More>

2007, 7(2): 29-35.

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Determining method of mixing and compaction temperatures for modified asphalt mixture

Zhang Zheng-qi, Li Ning-li, Chen Hua-xin

Abstract: In order to reasonably determine the mixing and compaction temperatures of modified asphalt mixture, gyratory compaction test was conducted on several modified asphalt mixtures, their volume parameters were analyzed, an optimal compaction temperature was obtained based on the compaction effect, and according to the relationship among the viscosity with the temperature and shear rate for mixture at the optimal compaction effect, a shear rate of 60 s^-1 was proposed to measure the viscosity of modified asphalt.Aimed at the shear rate, the viscosities at different temperatures and the viscosity-temperature curves could be got, and the mixing and compaction temperatures were determined with the viscosity request of(0.17±0.02) Pa·s and(0.28±0.03) Pa·s respectively.The difference between the compaction temperature obtained by the commended method and the temperature at the optimal compaction effect is 5 ℃, the temperature obtained by the commended method is in accordance with paving practice, which indicates that the commended method is reasonable.More>

2007, 7(2): 36-40.

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Performance comparison of asphalt macadam mixtures based on different molding methods

Wei Jian-guo, Cha Xu-dong, Zheng Jian-long, Wang Bing-gang

Abstract: In order to study the influences of different molding methods on the performances of asphalt macadam mixtures and the indices of mixture tests, three molding methods were utilized, including large scale Marshall molding method, rolling molding method and vibrating molding method, the Marshall indices of asphalt macadam mixtures compacted by the three methods were compared, and the volume indices of asphalt macadam mixtures with different vibration times were analyzed.Based on the principle of same compaction power, the ranges of four indices designed by using rolling molding method and vibrating molding method were put forward aimed at asphalt macadam mixtures.Test result shows that the ranges of different indices aimed at the two methods are nearly same, only with a difference of 5% in asphalt saturation degree, and enough compaction time is required for asphalt macadam mixtures in construction and compaction, so that they have good road performances.More>

2007, 7(2): 41-45.

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Computation method of interfacial stresses between CFRP and concrete

Cheng Yong-chun, Li Chun-liang, Liu Han-bing, Wang Bo

Abstract: In order to study the shear stress distribution law of adhesive layer and determine the debonding failure on CFRP (carbon fibre reinforced plastic) and concrete interface in concrete strengthened structure with CFRP, a tensile test with CFRP reinforced concrete specimen was maked out, and a calculation model of arbitrary point interfacial shear stress and strain was put forward based on elasticity theory.Computation result indicates that the computation result of stresses is coincidence with the test result, the model is feasible; the computation value of interfacial ultimate shear strength is 3.96 MPa, so the shear stress should be less than the value in order to prevent the debonding failure.More>

2007, 7(2): 46-49.

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Estimating method of fatigue life during cracking initiation of asphalt pavement based on modified Neuber equation

Yang Jian-gang, Wang Bing-gang, Chen Shuan-fa

Abstract: To estimate the fatigue life of asphalt mixture during the cracking initiation of asphalt pavement, its true stress and strain loop curve was established by direct tension test based on partial stress and strain theory, its nominal stress and strain were converted into partial stress and strain through Neuber equation, and its loop curve and Neuber equation were modified in order to meet the question of plain stress.The fatigue equation of asphalt mixture was established by isostrain fatigue test, and an estimating method of fatigue life was put forward.It is pointed that the fatigue damage of asphalt mixture can be reasonably calculated by its strain fatigue life curve, and its fatigue life during the cracking initiation of asphalt pavement can be estimated by its cumulation damage.More>

2007, 7(2): 50-54.

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Properties of acoustics and vibration of skeleton dense quiet pavement

Cao Wei-dong, Yang Yong-shun, Lu Wei-min

Abstract: In order to study the noise reduction mechanism of skeleton dense quiet pavement(SDQP), the absorption coefficient, complex moduli of SDQP mixture and the properties of vertical vibration attenuation of tire aimed at different pavements were tested by respectively using standing-wave meter, repetitive loading method and tire/pavement vibration test system.Test result shows that the absorption coefficient of SDQP is close to that of SMA, the values of the absorption coefficients are very small in all frequency bands, and the dynamic moduli of SDQP decreases with the increase of rubber granules content, while the damping of SDQP increases; the attenuation coefficient of tire placed on SDQP is the maximum, and increases with the increase of rubber granules content, which indicates that SDQP has good noise reduction ability of damping and vibration attenuation, and the primary mechanism of noise reduction is not sound absorption.More>

2007, 7(2): 55-58.

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3-D consolidation numerical calculation of loess-high embankment

Jing Hong-jun,

Hu Chang-shun

, Wang Bing-gang, Ding Ning, Li Yue-cai

Abstract: According to the structural, under-compressible, unsaturated and anisotropic characters of loess, loess was regarded as unsaturated soil, its 3-D consolidation equations were derived based on unsaturated soil theory, and its consolidation deformation characters were analyzed by FEM.It is pointed that compressed subgrade settlement deformation appears "sag" shape, its maximum settlement lies in embackment center, embackment shoulder settlement is minimum, and 1/3~2/3 of embankment high appears outward "extrusion" tendency; stress change tendency is inward and downward increasing, and minimum shear stress lies in slope toe; for unsaturated soil, after instantaneous loading, its surface settlement contains instantaneous settlement and soil mass consolidation settlement, and the former is main deformation.Analysis result shows derived unsaturated loess 3-D consolidation equations can well simulate and analyze the consolidation deformation of loess embankment, and its application prospect is quite good.More>

2007, 7(2): 59-64.

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Permafrost subgrade deformation forecast based on phase space reconstruction and partial least squares regression

Hou Shu-guang, Wang Shuang-jie

Abstract: In order to accurately forecast permafrost subgrade deformation, a single variable chaos time series of permafrost subgrade deformation was constructed in multidimensional phase space, some independent variables, function and sample numbers were defined according to embeded 38 dimensions of the space, the main components of independent variables were picked by using partial least squares regression method, a deformation forecast model was constructed, the precision of the model was analyzed by recurring multiplicate evaluation indices, and the comparative figure between forecast values and measure values was plotted.Analysis result shows that all sample points concentrate near the diagonal line of the figure, their correlation index is 0.889 4, their maximum relative error is 9.75%, which indicates that the model is reasonable and credible, can forecast subgrade deformation in permafrost regions.More>

2007, 7(2): 65-69.

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Settlement prediction model of wettest-soft loess subgrade in ravine regions

Peng Xiao-yun, Ye Wan-jun, She Xue-sen, Zhao Juan, Liu Zhao

Abstract: In view of the randomness and uncertainty of effect factors in subgrade settlement prediction, a prediction model based on case-based reasoning integrated with neural network was presented.In the model, a model for indexing subgrade settlement cases with neural network was set up, the successful experiences of similar engineerings were analyzed, and a new kind of utility function to calculate the similarities of the cases were introduced.The similarity relationship among the settlement cases was established by training neural network, so that the most similar base case to settlement target case was found out.Settlement prediction result of wettest-soft loess subgrade in ravine regions shows that the absalute errors between predicted data and actual ones are less than 10%, and the model has high prediction precision.More>

2007, 7(2): 70-75.

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Calculation method of antifreezing layer thickness in cold region tunnel

Chen Jian-xun, Luo Yan-bin

Abstract: In order to determine the optimum thickness of antifreezing layer of highway tunnel in cold region, the thickness was computed by separately using equivalent thickness conversion method, weather analytic method and finite element simulation method.Calculation result shows that aimed at former two kinds of methods, the antifreezing layer thickness is less than 1 cm when it lies between the primary support and the lining, and less than 2 cm when it lies on the lining surface, which are consistent with the practice; the relevant values are 3.2 cm and 4.4 cm respectively aimed at finite element simulation method, which are bigger than the thicknesses of antifreezing layer in reality; the result of finite element simulation calculation is excessively safe for the structure, the computation process of weather analytic method is complex, the computation process of equivalent thickness conversion method is easy and can be applied in engineering practice; the antifreezing layer is suitable to be laid between the primary support and the lining to save money.More>

2007, 7(2): 76-79.

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System optimization equilibrium model of parking and riding based on road section and parking impedances

Shen Jia-jun, Wang Wei, Chen Jun

Abstract: In order to select parking and riding(P&R) establishment effectively and reasonably, road section saturation and parking availability were regarded as two main factors, and a system optimization equilibrium model (SO) aiming at minimizing gross road section and parking impedances was established, which served the users' parking behaviors of the establishment. The solution uniqueness of the model was proved by constructing Hessian matrix, and the steps to solve the model were summarized. Calculation result of an example shows that the parking distribution quantities of three establishments are 259, 340 and 421 veh respectively, the demand of the model is less, its solving steps are simple, and it may gain better practical effect when it is applied with parking guidance information system. 1 tab, 1 fig, 12 refs.More>

2007, 7(2): 80-83.

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Forecast model of parking demand based on land function and traffic characteristics

Wang Feng-yuan, Zou Xu-dong, Yan Yan, Li Hong-min, Zhang Hong-hai

Abstract: In order to solve urban parking difficulty and reasonably forecast urban parking demand, the limitation of land resource and the increase of traffic flow were considered, the principle of parking demand forecast model with land function and traffic effect was analysed, the relation of land use property and dynamic parking generation rate was depicted by land use character function, and the influences of the increase rate of traffic flow and parking rate on parking demand were analyzed by traffic influence function.A parking demand forecast model was constructed, the algorithm and the program of the model were developed, and the parking demand of a typical region was forecasted based on its land planning data and practical road traffic flow data.Forecast result shows that parking demand increases slowly in recent 5 a and quickly in following 5 a, the increase speed of everyday parking demand is higher than that of rush hour.More>

2007, 7(2): 84-88.

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Nonlinear optimization model and algorithm of urban curb parking setting scale

Mei Zhen-yu, Chen Jun, Wang Wei

Abstract: In order to form the proper matching relationship between curb parking and off-street parking, decrease parking cost, the matching relationship was analyzed, the parking choice behaviors of drivers were studied, the social costs of curb parking and road vehicle travelling were analyzed separately, the effect of curb parking on traffic delay, the circuitous distance, charge balance and individual time benefit of parking were considered synthetically, an optimization model of urban curb parking setting scale based on minimizing parking cost was put forward, and an inner-spot algorithm of the model was designed.Calculation result shows that the average parking circuitous distance of travelling vehicle and whole parking cost are decreased by 63.0% and 37.3% respectively.It is obvious that the optimization model can optimize the matching relationship between curb parking and off-street parking, and minimize parking system integrated cost.More>

2007, 7(2): 89-93.

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Road safety level evaluation based on grey fixed weight clustering model and factors analysis

Xu Hong-guo, Liu Zhao-hui, Wang Chao

Abstract: In order to determine the holistic traffic safety levels of higher-class highways in a district, and distinguish the influence degrees of road factors on traffic safety, grey clustering theory of whitenization weight function, fuzzy theory and analytic hierarchy process (AHP) were studied, a new synthesized method for evaluating road safety level was put forward.Higher-class highways in a district were categorized into several safety grades by utilizing grey fixed weight clustering.The weight of each clustering criterion was determined by adopting fuzzy consistency matrix.Main road factors that influenced traffic safety were quantificationally analyzed by using AHP.Analysis result of an example shows that highway No.5 belongs to the grey group of low safety grade, its namely alignment combination, safeguard facilities, sight distance and mixed degree are main reasons to result in the low safety grade.Which indicates that the method can objectively compartmentalize the traffic safety levels of higher-class highways, give a reasonable order of the factors that affected traffic safety, and realize the systematic evaluation of road traffic safety.More>

2007, 7(2): 94-98.

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Noise reduction effect of noise barrier made of sound-absorbed bricks with resonance cavities along expressway

Yuan Wei-ning, Dong Xiao-lin, Zhang Yu-fen

Abstract: In order to solve the problem of acoustic environment impact resulted from traffic noise on the villages along expressway, the traffic noise of constructed expressway was monitored, a forecasting model of traffic noise was given to calculate the traffic noise levels, and a noise reduction method was proposed, that noise barrier was made of sound-absorbed bricks with resonance cavities on both sides of expressway.Noise barrier engineering and noise monitoring result indicate that the method is feasible, the noise level is decreased by 13~16 dB, the structure of the barrier is simple, its cost is low, its construction is easy, and its environment and economic benefits are obvious.More>

2007, 7(2): 99-103.

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Stochastic saturation entropy model of passenger transportation structure configuration for comprehensive transportation corridor

Qiu Yu-zhuo, Chen Sen-fa

Abstract: In order to find a systematic and scientific method to optimize the passenger transportation sharing rate of comprehensive transportation corridor, a passenger transportation structure configuration model was put forward based on the maximum entropy theory.In the model, passenger chose transportation mode, so that generalized travel time based on stochastic time value was least, the saturation degree of basic links in the corridor and corridor saturation entropy were defined, and a particle swarm algorithm was designed to solve the model.Analysis result shows that the sharing rates of various transportation modes depend on the differences of out-of-vehicle times, the differences of unit distance prices, the differences of unit distance travel times and travel distances; rail optimal pricing is higher than the current one, the saturation entropy has an increase of 15%, which means that low rail pricing result in the over saturation of passenger flow; the optimal passenger transportation sharing rate can reduce the differences between the saturation degrees of various transportation modes on the basic links in the corridor, and realize the effective match between transportation demand and supply.More>

2007, 7(2): 104-108.

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Two-phase tabu search algorithm of unloading operation scheduling project in container wharf

Ceng Qing-cheng, Yang Zhong-zhen

Abstract: In order to improve the unloading efficiency of container wharf, a integrated optimization model of storage location and yard trailer scheduling was developed, and a two-phase tabu search(TS) algorithm was designed to solve the model.In the first phase, a TS was performed to determine a good storage location scheme.In the second phase, for each storage location scheme obtained during the first phase, another TS was run to obtain a good yard trailer scheduling project, and then to calculated container unloading time, so as to influence the TS in the first phase.The optimal scheduling project was formed by the feedback and reciprocity between the two phases.Computation result shows that the algorithm can decrease container unloading time 6.78% in average, and the computation values are stable.More>

2007, 7(2): 109-112.

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Operating mechanism of logistics concentrating goods based on stochastic service process

Xia Wei-huai, Chen Zhi-ya

Abstract: In order to raise the concentrating goods operating management efficiency of logistics network joints(logistics centers), the process and characteristic of concentrating goods were described by applying stochastic service system theory and method, concentrating goods operating mode(CGOM) was compared with decentralized operating mode(DOM), the operating mechanism of concentrating goods was studied, and CGOM's model(Markov queuing model) was constructed.The analysis result of a example indicates that the system running indices of CGOM are obviously superior to that of DOM, its service facilities' utilization ratio increases by 23.4%, system goods average staying time decreases by 56.12%;especially, its system running indices' change of DOM is rapid when system busy degree is 90%, but that of CGOM is not obvious, and the goods average staying time in CGOM system is less than 1/5 of that in DOM system.More>

2007, 7(2): 113-116.

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Combinatorial optimization algorithm of rapid road repair and material distribution after disaster

Zhang Yi, Guo Xiao-fen, Li Jin-hui

Abstract: In order to obtain the highest road repair benefit and the optimized material distribution project within limited time, and enhance relief efficiency after disaster, the problems of rapid road repair and material distribution after disaster were analyzed, their time-space networks were respectively constructed by using the flowing technique of time-space network, the relativity between rapid road repair and material distribution was considered, a multi-objective mixed integer-multiple network programming model was founded relating with rapid road repair engineering and urgency material distribution after disaster, and a decomposition heuristic algorithm was put forward.The calculated result of an instance shows that it takes 106.9 h to obtain the optimized solution of the model with CPLEX math programming software, while it only takes 31.8 min with the algorithm.Its calculation efficiency is high, and the calculation time is acceptable in actual relief work after disaster.More>

2007, 7(2): 117-122.

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Optimization model of economic scale of agricultural products logistics center

Pang Sheng-ming, Wei Lang

Abstract: In order to optimize the economic scale of agricultural products logistics center, its production function, scale profit ratio and economic behavior were analyzed, and the relation of scale profit ratio and logistics center scale was calculated.Shouguang logistics center of agricultural products was taken as an example to validate the optimized model.Calculation result shows that the scale profit ratio is in the determination scope of the model, it begins to increase with the growing of labor and capital investments, and then to decrease with the continuous growing, which indicates that the optimized model is feasible, can be used to evaluate economic property of the operational scale of logistics center.More>

2007, 7(2): 123-126.

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