交通运输工程学报

Influence of lateral damper on locomotive riding quality

LIU Jian-xin, WANG Kai-yun, FENG Quan-bao, ZHAO Huai-yun

Abstract: Based on vehicle-track coupling dynamics, with simulation software TTISIM, the effects of the parameters, working condition, unloading velocity and position of lateral damper on the running performance of speed-raised locomotive were systematically investigated.Analysis result shows that it can improve locomotive riding performance to choose proper damping parameters and unloading velocity, the working condition of lateral damper has great effect on locomotive riding quality, so it must be ensured that all of dampers are in normal working states when locomotive runs on railway, its running performance is not sensitive to damper position.More>

2006, 6(3): 1-4.

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Aerodynamic performance of sidewall shape of boxcar under strong crosswind

TIAN Hong-qi, MIAO Xiu-juan, GAO Guang-jun

Abstract: The transverse force and air lift force caused by strong crosswind are the main factors of train overturning, unloaded boxcar can easily be overturned by strong crosswind because of its large sidewall area and underweight.So flow field numerical computation was completed in order to look for an optimum project of sidewall shape among the upright sidewall, bulgy-arc sidewall and bulgy-slope sidewall, the aerodynamic performance of boxcar suffering from crosswind was studied, such as the transverse air force, air lift force and overturning moment.The result shows the bulgy-arc sidewall and bulgy-slope sidewall can reduce the overturning moment effectively and improve train's stability under strong crosswind to greater extent than the upright sidewall, when the width of boxcar is 3.2 m, boxcar sidewall with bulgy-arc and bulgy-slope compared with upright, its coefficient of overturning moment decreases to about 21% and the critical wind speed increases to 2.7 m²·s^-1 for unloaded boxcar.More>

2006, 6(3): 5-8.

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Running safety and comfortability simulation of railway

WANG Kai-yun, LIU Jian-xin, ZHAI Wan-ming, CAI Cheng-biao

Abstract: In order to investigate the running safety and comfortability of train with a maximum speed of 200 km·h^-1, on the basis of system engineering and dynamics point, the indices of all kinds of trains at different speeds were calculated for mixed railway with passenger and freight traffic.With the railway vehicle and locomotive specification for the evaluation of dynamics performance and accreditation test, train running safety and comfortability were evaluated systematically.The result shows that all dynamics indices belong to safety grade and there are much of overmeasure under operating condition, especially, the ridding indices belong to fine grade.More>

2006, 6(3): 9-12.

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Model of ground vibration generated by slab track

HE Zhen-xing, ZHAI Wan-ming

Abstract: A model was established for the study of ground vibrations generated by slab track that was subject to a unit force, the characteristics of slab track were considered, ground was modeled as a number of infinite-parallel-homogeneous-elastic layers overlying elastic half-space, the dynamic differential equations of the system were solved in wave-number domain, and then the vertical displacement amplitude of ground surface was obtained by implementing inverse Fourier transform.The applied result of the model shows that the dispersion characteristics of the vibrations propagating in ground can be demonstrated, the load speed has significant influence on ground vibrations, the spread scope and response amplitude of vibrations increase with load speed increase, Doppler effects occur when the speed is greater than Rayleigh wave speed, which indicates that the model can simulate the alluvial depositing stratification characteristics of ground.More>

2006, 6(3): 13-17.

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Numerical value comparison of micro-pressure wave in reduction by using hoods at high-speed railway tunnel exit

GENG Feng, ZHANG Qian, MEI Yuan-gui

Abstract: Based on analyzing the generating mechanism of micro-pressure wave at high-speed railway tunnel exit, with one-dimensional unsteady-compressible-nonisentropic air flow theory and round-piston radiation theory with infinite baffle plate, the rules of micro-pressure waves generated by high-speed train near tunnel exit under different shape hoods were studied, the influences of various shapes and parameters of hoods on the waves were qualitatively and quantitatively analyzed.It is indicated that the wave intensity evidently decrease with the length and cross-section area increasing of line-type, parabola-shaped and discontinuous-type hoods, the effect of discontinuous-type hood is evidentest; when hood cross-section area is constant, but hood construction is perforated, the choice for the best structural parameters needs an integrated plan contrast although the wave intensity can be greatly reduced.More>

2006, 6(3): 18-22.

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Computation model of rupture force between continuously welded rail and high-speed railway bridge

XU Qing-yuan, WANG Ping, QU Xiao-hui

Abstract: Based on the study achievements of some predecessors, bridge, pier and abutment were simulated by solid element, rail and sleeper were simulated by space beam element, the links of rail, sleeper, bridge, pier and abutment were simulated by spring element, a three-dimensional finite element spatial mechanics model for calculating the rupture force between continuously welded rail and high-speed railway bridge was established.Taking a 10-span-32 m simply supported double-track box girder beam bridge in Qin-Shen passenger special line as an example, the influence factors of rail gap were analyzed.The result shows that bridge temperature variation amplitude, bearing frictional force and rail gap position have little influence on rail gap, fastener longitudinal resistance, rail temperature variation amplitude, rail type and pier longitudinal stiffness have remarkable influence on rail gap, mechanics models also have some influence on rail gap, the computation result of new three-dimensional spatial model is lesser compared with traditional plane model.More>

2006, 6(3): 23-26.

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Joint sealant performance of cement concrete pavement

TAN Zhi-ming, SUN Ming-wei, LI Li-han

Abstract: The model composed of one viscous and two elastic elements was used to simulate the viscoelastic performances of silicone, polyurethane, rubber asphalt, PVC modified asphalt and polyvinyl chloride mortar, some regressive formulas of the viscoelastic parameter of sealant were provided, the computing approaches of sealant tensile stress arising out of temperature drop and sealant shearing stress caused by vehicle load were established, a limit state equation related to sealant stripping out of joint wall was developed, and the road service performance of experimental sealant was analyzed and evaluated accordingly.It is found that the adhesive failure of sealant mostly arises from the shear stress caused by vehicle load, the primary cause is of sealant stiffness at low temperature under high frequency shearing condition, whereas the tensile stress arising out of temperature drop is subordinate.More>

2006, 6(3): 27-31.

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Grey relation degree analysis of high-temperature performance indexes of asphalt

WANG Peng, CENG Fan-qi, HUANG Xiao-ming

Abstract: In order to improve the high-temperature performance indexes of asphalt, the theory of grey relation degree was applied to calculate the relation degrees between 60 ℃ asphalt viscosity, 135 ℃ modified asphalt viscosity, their softening points and asphalt G^*/sinδ, other high-temperature performance indexes.It is pointed that the relation degree between 60 ℃ asphalt viscosity and asphaltG^*/sinδ is better, the value reaches above 0.800, the relation degrees between 60 ℃ asphalt viscosity, 135 ℃ modified asphalt viscosity by short-term aging and asphalt G^*/sinδ are also better, the maximum value is 0.897, but the relation degrees between softening point and other high-temperature performance indexes are not better.The result indicates that asphalt G^*/sinδ cann't reflect the high-temperature performance of modified asphalt, but asphalt G^*/sinδ by short-term aging may reflect the performance, softening point used to evaluate the high-temperature performance of asphalt need further research.More>

2006, 6(3): 32-36.

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Reliability index analysis of internal stability of reinforced embankment

QUE Yun, LING Jian-ming, CENG Si-ping

Abstract: In order to perfect the reliability design method of reinforced embankment, Monte-Carlo method was adopted to analyze the relations between the design parametric random variables and internal stability reliability index of reinforced embankment.Analysis result indicates that the internal stability is better when the density is lower, and the parameters, such as the cohesion, internal friction angle, geosynthetics tensile strength and pseudo-friction coefficient, are larger.The internal stability reliability index is sensitive to the variation coefficients of the design parameters.Except the internal friction angle, other different probabilistic models of the design parametric random variables and the design loads of different highway classes have little influence on the internal stability.Perhaps the internal stability is improved while light filler with high cohesion and big internal friction angle and high strength geosynthetics are used in the reliability design.The reliability tend to be safe while filler density accords with extremal typeⅠlargest distribution, the cohesion, internal friction angle, geosynthetics tensile strength and pseudo-friction coefficient accord with normal distribution.More>

2006, 6(3): 37-41.

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Stability computation method of highway loess dam-like embankment

XU Shi-qiang, ZHE Xue-sen, LIU Yi-lin, ZHENG Nan-xiang, ZHOU Zhi-jun, SHI Gang

Abstract: In order to improve the stability of upper slanting waterproof highway loess dam-like embankment, earthquake effect on slope stability was analyzed, the calculation formula of slope stability coefficient was deduced by introducing earthquake parameter and using simplified Bishop method, the water pressure action and mechanical balance principle of the embankment were studied, its whole stability judgment qualification was got.The calculation result of slope stability shows that earthquake effect on slope stability is great, the minimal error of slope stability coefficient is 0.1 (earthquake intensity is 7°) in the conditions of earthquake and no earthquake, relative to the slippery points out of slope bottom and on slope, the slope stability coefficient of the former is less than that of the latter, the stability coefficient value that slope is immersed in water is less than the value that slope is not immersed in water, the slippery point position, immersed state and earthquake effect must be considered when the stability is computed.The whole stability calculation result of the embankment shows that the embankment is safe when ditch gradient is 2.872%, the embankment is ruin when ditch gradient is 10.000%, so loess dam-like embankment must be built on placid ditch.More>

2006, 6(3): 42-46.

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Architecture of expressway maintenance management system based on SDSS

ZOU Guo-ping, ZOU Qun, HUANG Zheng

Abstract: Present expressway maintenance management system (EMMS) is a simple decision support system (DSS), its decision-making is drived by model, and its intelligent level of decision-making is lower.The EMMS based on synthetic decision support system (SDSS) was presented in order to improve the ability and intelligent level of expressway maintenance decision-making, it integrated intelligence decision support system (IDSS) and business intelligence (BI) technology, and drived the system decision-making by model, knowledge and data.The system is composed of data warehouse (DW), on line analytical processing (OLAP), data mining (DM), model storehouse, knowledge storehouse and database.DW can store and synthetize the data of decision theme, OLAP can realize multi-dimension data analysis, DM can mine the knowledge from database and DW, model storehouse can realize combination assistant decision-making by many generalized models, database can provide data for assistant decision-making, expert system (ES) can realize qualitative analysis by knowledge reasoning.The integrated system can exert its each advantage, and realize more effective assistant decision-making by their mutual makeup and dependence.More>

2006, 6(3): 47-50.

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Mechanics property and adaptability of approach slab

YU Yong-hua, XIE Yong-li, YANG Xiao-hua

Abstract: With MARC program, subroutine program of simulating vehicle moving load, contact iterative computing method and element life-death technique, the different mechanics states of contact and separation between slab and filling were simulated, on the basis of different foundation settlement modes, the coupling action of slab internal force and deformation was considered, the mechanics property and adaptability of slab were researched.The result shows that the flexural-tensile stress at the bottom of slab is not influenced when the length of slab separation section is less than 1.08 m, observably increases with the increase of the length, and the loading position of the maximum flexural-tensile stress at the bottom of slab is between the abutment and half of length of slab; the slab of length 6 m is suitable for treating the foundation that the settlement value is less than 3 cm, 8 m for 4 cm, 10 m for 5 cm.More>

2006, 6(3): 51-56.

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Mechanical behavior of concrete filled circular steel tubular stub columns with axial pre-stress in steel tube

DING Fa-xing, YU Zhi-wu

Abstract: Based on continuum mechanics, the calculation model for concrete filled circular steel tubes of concentric cylinders of circular steel tube with concrete core of entire section loaded with axial pre-stress in steel tube was determined, the theoretical calculation formulas for composite elastic modulus and composite stress-strain relationship of concrete filled circular steel tubular (CFST) stub columns with axial pre-stress in steel tube were presented, the axial stress-axial strain relationship of steel tube, the perimeter stress-strain relationship of steel tube, the axial stress-axial stain relationship and the radial stress-axial strain relationship of concrete core were analyzed, and the influence of the axial pre-stress ratio on mechanical behavior of columns was discussed.Analysis result indicates that the axial stiffness, radial stress, and axial strength of concrete core and the perimeter stress of steel tube decrease with the axial pre-stress increasing of steel tube, but the axial stress of steel tube increases, the confinement effect and ultimate capacity decrease, but the composite elastic modulus is hardly influenced.More>

2006, 6(3): 57-61.

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Capacity evaluation of RC girder bridge with vibration testing technique

ZHOU Mi, HE Shuan-hai, YUAN Wan-cheng

Abstract: Dynamic parameters were used to evaluate the loading capability of existing RC girder bridge. According to the experimental results of damnification test on four pieces of RC simple T-beam and applying nonlinear regression analysis method, some equations expressing the relation of the stiffness ratio and frequency ratio of T-beam were obtained, a relation of the structural dynamic characteristic and bearing capacity of RC single beam was proposed. Based on the measured basic frequency and crack characteristic, the dynamic characteristic of the whole bridge was divided into the dynamic properties of single beams. So the model of dynamic assessment was expressed, structural basic frequency and crack characteristic→rigidity→nominal ratio of reinforcement→resistance to bending of single beam. In the dynamic assessment of a actual RC simple bridge, the deflection-controlling bending moment, crackcontrolling bending moment and intensity-controlling bending moment of single beam are obtained, the evaluation result of vibration method is accurate and accordant to static test result, which indicates that the frequency and crack characteristic can be used to forecast the loading capability of existing RC girder bridge. 3 tabs, 9 figs, 9 refs.More>

2006, 6(3): 62-67.

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Secondary lining thickness optimization of road tunnel

CHEN Jian-xun, LI Jian-an

Abstract: Engineering analog method was adopted to take the secondary lining thickness optimum design of Yushugou tunnel, shallow-buried Ⅱ class rock, Ⅲ class rock and Ⅳ class rock, which are three different kinds of composite lining structure types, were selected, the software FLAC was used to take analog computation on the surrounding rock and primary support's strained condition after the tunnel was excavated, then the software ANSYS was used to take analytical computation on the strained condition of the secondary lining.Computation result indicates that the secondary lining's internal forces of three different kinds of lining structure types are less, the maximal stress is 165 kN, the maximal bending moment is-15.97 kN·m, and both of them happen in the section of shallow-buried Ⅱ class rock, the safety factor of the secondary lining is large; the maximal circumjacent displacement of the lining occurs in the situation of shallow buried Ⅱ class rock, the maximal displacement (18 mm) of the surrounding portal happens in spring, the surrounding rock displacement in side wall has a less convergence, the better the surrounding rock is, the smaller the circumjacent displacement is.The result of monitoring measurement indicates that the convergence of tunnel inner perimeter is far smaller than allowed convergence, the measured pressure values of contact surface in the secondary lining are smaller than the calculated values in specification, the secondary lining has good work condition and its safe provision is enough, so tunnel structure is safe when reducing the thickness of secondary lining.More>

2006, 6(3): 68-72.

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Ultrasonic-tomography system for nondestructive concrete structure testing

SONG Huan-sheng, ZHAO Xiang-mo, WANG Guo-qiang, QI Xiu-zhen

Abstract: The safety supervision and quality evaluation of bridges, tunnels and buildings require the nondestructive testing of their inner properties.Conventional ultrasonic testing equipment only processes one-dimension signals that it receives, from which it is hard to get a clear description of the concrete structures.So a new ultrasonic-tomography system was developed, a specially designed great power and short pulse ultrasonic emitter was used.The ultrasonic signals passing through the concrete structures were captured by high speed signal acquisition circuit.The inner features of the concrete structures were computed by improved fast ART algorithm.In the detection test of the inner defects of concrete sample, the tomography image produced by the system clearly shows the inner structure of test sample.In another bridge pier intensity test, the new system produces bridge intensity tomography images, which are coincident with the detection results by rebound measurer.The experiment results show that the developed system can reproduce the inner intensity distribution and defects of concrete structure, and can be effectively used for the safety supervision and quality evaluation of concrete construction.More>

2006, 6(3): 73-77.

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3-D modeling method of ship model surface for numerical control machining

ZHU Lin-sen, TANG Yang-ping, BIN Hong-zan, XIONG Cai-hua, LIU Ping

Abstract: In order to farthest make use of three sets of molded lines of ship model surface (SMS) so that SMS modeling contains more design information, SMS modeling effects realized by many kinds of surface modeling methods based on UG were analyzed, a modeling method of through curve mesh (TCM) for numerical machining of SMS was proposed, the key technologies of SMS 3-D modeling by TCM were studied, which are local region enveloping and surface partition, and SMS 3D modeling module was developed by UG/OpenGrip.It needs at least 30 d for traditional handcrafting manufacturing method to finish twin-skeg SMS, however, only 6 h is needed for 4-axis SMS NC (numerical control) machining system to finish 98% of the workload, the dimension precision, geometrical precision and fairing effect of SMS realized by the method are better than those realized by the traditional method, so the 3-D modeling precision of SMS realized by TCM can fully satisfy the requirements of numerical control machining, and is feasible.More>

2006, 6(3): 78-81.

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Co-scheduling model of Three Gorges-Gezhou Dam based on series queuing network

WANG Xiao-ping, QI Huan, XIAO Heng-hui, ZHANG Xiao-pan, HU Yang, FENG Xiao-jian

Abstract: In order to increase the whole passing ability of Three GorgesGezhou Dam, a mathematical model on the co-scheduling problem of Three GorgesGezhou Dam was given out, based on the analysis of its actual needs, two objective functions to maximize the utilization ratio of lock chamber and minimize the whole navigation lock waiting time were considered, along with eight constraint conditions during ship arrangements, a scheduling algorithm based on series queuing network was put out.In the algorithm, declarated ships were divided into four sequences and each ship's weight was calculated, ship's length and width priorities, navigation lock waiting time constraints, the navigable constraints of Gezhou Dam navigation lock and task equalizing conditions were considered, circularly scheduling ships and plan's step-by-step optimizations were carried out.Applied result shows that making a two-dam-five-gate plan only needs 2 min, the lock chamber utilization ratio of Gezhou Dam's 2^# gate is higher than 70%, and passenger ship and touring ship are arranged to the front, the waiting time restriction of passenger ship is satisfied, ship up-and-down running courses are alternant, no converse course occurs, which indicates that the plan is quite effective according to practical application.More>

2006, 6(3): 82-86.

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Traffic congestion identification method of urban expressway

JIANG Gui-yan, GANG Long-hui, WANG Jiang-feng

Abstract: In order to quickly identify traffic congestion from mass dynamic traffic information, traffic congestion pattern and the characteristics of various data mining technologies were analyzed, an auto-identifying method of urban expressway traffic congestion was designed.The flow, speed and occupancy of expressway were combined into several new eigenvectors, optimized multi-layer feedforward perceptron model was adopted to classify the eigenvectors during congestion and non-congestion, recurrent congestion and non-recurrent congestion could be distinguished by analyzing the variances of the model outputs, the method was tested with simulated data and actual data from an urban expressway. The result shows that the method has great practicability and can identify congestion states on urban expressway correctly.More>

2006, 6(3): 87-91.

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Elman neural network model of freeway dynamic traffic flow

LIANG Xin-rong, LIU Zhi-yong, MAO Zong-yuan

Abstract: In order to improve the accuracy of freeway traffic flow modeling, the discrete mathematical model of freeway dynamic traffic flow was analyzed, and a traffic flow model of recurrent neural network was built based on the principle of Elman network. The node numbers of the input layer, context layer, hidden layer and output layer of the recurrent network were selected as 8, 30, 30 and 2 respectively. Levenberg-Marquardt algorithm was used to train the recurrent network, and a freeway with five segments was simulated. Simulation result shows that the average relative error and the maximum relative error for the recurrent network are 8. 683 7 × 10^-5 and 4. 237 1 × 10^-4 respectively, compared with the BP and RBF neural network, the Elman recurrent network can approach the mathematical model of freeway traffic flow more accurately, can better describe the basic properties of traffic flow, and by means of on-line learning from the data measured by sensors on the freeway, the Elman recurrent network can adapt to the change of traffic status. 1 tab, 7 figs, 10 refs.More>

2006, 6(3): 92-96.

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Blocking problem of freeway side traffic signs

LI Wen-quan

Abstract: In order to improve the accurateness that car driver recognizes roadside signs on the inboard driveway of more-lanes freeway, the mathematical model and algorithm to deal with the blocking problem of roadside traffic signs were set up by using driver visiblity disciplinarian, vehicle arrival disciplinarian and probability computation methods, the individual approaches and methods for setting roadside traffic signs in sequence were obtained by the theoretical model, they were how to determine the location of roadside signs, calculate the length of blocking rectangle, calculate the shelter probability and choose the number of roadside signs set in sequence. The simulation result shows that the blocking probability varies from 2.1 ×10^-1 to 9.4×10^-5 when the number of roadside signs set in sequence varies from 1 to 6, the blocking probability exponentially decreases with the number increase that of roadside signs, which indicates that the established models and methods to set roadside traffic signs in sequence are feasible, it can solve the blocking problem of roadside traffic signs on freeway with more lanes. 2 tabs, 7 figs, 10 refs.More>

2006, 6(3): 97-102.

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Car-following model under influence of expressway accident

CHEN Bin, WEI Lang

Abstract: With agent technology and in view of car-following behavior under the influence of accidents happening on bidirectional four-carriageway expressway, a car-following model based on agent was established.In the description of vehicle agent properties, the quantitative analysis of its separation-desire was carried out according to the data of West China expressway traffic surveys and statistics, the acceleration of vehicle agent was determined by proportional-derivative control theory, the logic intention queue with different accelerations was set up, which made the acceleration response of the model comply with vehicle dynamic features.The model was tested both under specified condition and in random process according to EAD-simulation system.Test result shows that the model can represent the individuality, self-constraint characteristic and self-adaptability of vehicle agent, control its stability by the similar damped character of proportional-derivative control.More>

2006, 6(3): 103-108.

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Self-calibration three-dimension reconstruction model of traffic accident photographs

LU Guang-quan, XU Hong-guo, MA She-qiang, LI Yi-bing

Abstract: In order to survey traffic accident scene rapidly, a 3-D reconstruction model of traffic accident scene based on self-calibration using general digital camera was explored.The model was based on fundamental matrix, which was estimated by matched feature points, essential matrix can be calculated by it.Traffic accident scene was reconstructed after essential matrix was decomposed.It is proved that the traffic accident scene can be reconstructed without calibration reference points in scene, the difference between the reconstruction result and real 3-D data is only a scale factor.More>

2006, 6(3): 109-113.

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Driving route status recognition based on digital image technique

LIN Guang-yu, WEI Lang

Abstract: In order to monitor driver working states and vehicle traveling conditions at real time, the recognition property of driving routes relative to road traffic mark was analyzed by using the images taken from on-board CCD image sensor, the models of perspective projection and vehicle traveling routes recognition were established by image understanding and computer vision techniques, the vehicle's real three-dimensional positions relative to road traffic mark from the dots of planar images were computed.Computation result shows that vehicle's calculation traveling routes are coincident with reality, so that driver's some peccancy behaviors, such as driving along solid central-line, driving across solid central line and driving along converse roadway, can be decided correctly.More>

2006, 6(3): 114-117.

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Model and heuristic solution for location routing problems of logistics network

CHEN Song-yan, JIN Jing-zhao-fu

Abstract: The minimum cost related to the process, in which goods are delivered from suppliers, through logistics centers (or distribution centers) to ultimate customers, was taken as the object function, MSDLRP (multi-supplier multi-depot location routing problem) was presented, including the optimal number and locations of suppliers, the optimal number and locations of distribution centers, the optimal routes from distribution centers to ultimate customers, a mathematic model of the problem was put forward, a mixed heuristic solution was developed by using traditional heuristic solution and simulated annealing solution, they were tested by manually generated data and studied cases.For small-scaled problem, compared with the optimal result got by using planning software, MSDLRP can be described by the mathematic model accurately, the problem can be solved by the heuristic solution during short period, and the optimal result is obtained.For big-scaled problem, although the optimal result can not be got, the result also is better.More>

2006, 6(3): 118-121.

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Basic point of integrated transport planning theory

WU Qun-qi, SUN Qi-peng

Abstract: In order to realize the coordination of all kinds of transport modes in the condition of market economy, current integrated transport theory was analyzed, by which some questions of transportation were difficult to be dealed with, such as promoting transport ability, transport's sustainable development, realizing transport's essential aims, transport's harmonizing development, because the diversification, multi-level demands and satisfaction degree difference of transport supplies were not reflected.It is pointed that the economic characteristics of all kinds of transport modes are the basic point of forming integrated transport planning theory, based on regarding transport demands as predominance and combining the specific condition of application to analyze the technology economic characteristics of transport modes, which may be realized, the organic unification between amount equilibrium and economic equilibrium can be indicated, and the properties belong to dynamic technology economy characteristics.7 refs.More>

2006, 6(3): 122-126.

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