2014 Vol. 14, No. 5

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Road and railway engineering
Influence of AC-25 particle size distribution on gradation segregation
PENG Yu-hua, HU Jia-yin, HU Shun-feng
Abstract: Seven kinds of asphalt mixtures with typical gradations were produced by adjusting the scale of hot bunker of mixing plant in AC-25 gradation range.By Bailey method, AC-25 aggregate was divided into five gradation intervals such as 0-0.3, 0.3-1.18, 1.18-4.75, 4.75-13.2 and 13.2-31.5 mm.The grey relation degree of aggregate content and gradation segregation in each interval was calculated by gray relation method.Analysis result shows that the grey relation degree reflects the influence of aggregate content on gradation segregation in AC-25 gradation range very well.The relation degrees decrease in the order of 4.75-13.2, 0.3-1.18, 0-0.3, 1.18-4.75 and 13.2-31.5 mm.The relation degree is maximal in 4.75-13.2 mm, which illustrates that the variation of aggregate content in the interval has great effect on the final gradation variability of pavement, so a good segregation resistance gradation is obtained by adjusting the aggregate content.The relation degrees are smaller in 1.18-4.75 and 13.2-31.5 mm, which shows that coarse aggregate and the coarse part of fine aggregate have less influence on gradation segregation.The quadratic regression relation coefficient of aggregate content and gradation segregation in each interval is more than 0.6, which shows that the interaction amongaggregates has great influence on final gradation segregation, the segregation characteristic of aggregate gradation possibly weakens when the influence of single passing rate on the performance of asphalt mixture is considered only, so the segregation resistance performance of asphalt mixture gradation must be analyzed from different grain sizes'combination angle.More>
2014, 14(5): 1-7.
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Centrifugal model test and numerical simulation of pressure grouting in subgrade retrofitting
QIU Yan-jun, LIU Yu-liang, YANG En-hui, XIANG Ke-ming
Abstract: In the practice of pressure grouting in subgrade retrofitting project of Mianyang-Guanyuan Highway, field monitoring, centrifugal model test and numerical simulation were carried out to study the technical process and the influencing factors of pressure grouting in subgrade disease.It is revealed that the geometrical property of subgrade section is the main reason to the differential settlement of subgrade, and then produces pavement premature failure such as longitudinal cracking.Centrifugal model test indicates that two-phase grouting method that with 0.2 MPa at the first stage and 0.4-0.5MPa at the second stage is recommended.The recommended reasonable space between grouting holes is 2.0 m.Economy should be considered in the practice for choosing reasonable concrete mix proportion and maintenance time.Numerical simulation result shows that there are three stages for pressure grouting, such as stress accumulation stage, cracking extension stage and crack widening stage.The pressure for soil splitting increases with the increases of homogeneity and soil strength.More>
2014, 14(5): 8-18.
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Bending behavior test of hybrid high performance steel beam
DUAN Lan, TANG You-ming, WANG Chun-sheng, WANG Ji-ming
Abstract: Bending behavior tests were conducted for 3 hybrid high performance HPS 485 W I-shape steel beams with the method of two-point loading.The influences of cross profile geometric parameters on bending capacity, elastic and plastic deformations, and failure mode of test beam were analyzed.Considering the test results under midspan one-point loading, the influences of different loading methods on bending capacity of test beam were analyzed.Finite element models were established to accurately simulate bending procedures of test beams.Parameter analysis was conducted for hybrid high performance steel beams under the condition of non-compact cross profile.Analysis result shows that the failure modes of two-point loading test beams are local bucklings at both compressive flange and compressive web in pure bending field.The plastic rotation capacity of steel beam increases obviously with the decrease of flange width to thickness ratio.The bending capacity and ductility decrease with the increase of web height to thickness ratio.For beams with same dimension, the bending procedures are similar when adopting different loading methods, but the buckling modes marking the failure of beam are different.It is suggested for hybrid steel beam that the steel grade of web should be not beyond two grades lower than the strength grade of flange.More>
2014, 14(5): 19-28.
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Complementary ventilation operational test in large longitudinal slope double-hole tunnel
WANG Ya-qiong, HU Yan-jie, DENG Min, XIA Feng-yong, XIE Yong-li
Abstract: In order to solve the technical problem that whether ventilation shafts are needed to set up or not in upstream tunnel when the air inflow and outflow are imbalanced in the large longitudinal slope double-hole tunnel, Dabie Mountain Highway Tunnel was selected as an entity engineering for analysis.The CO concentration, visibility index, and air velocity in the complementary network ventilation tunnel were tested on site, and the effect and existing problem of ventilation channel in the double-hole complimentary network ventilation system were analyzed.Test result indicates that the complimentary network ventilation can meet the control criteria of contaminant concentration.Two ventilation channels can play the role of airflow bi-direction exchange, and the exchanged air volume can meet design requirement, therefore, the complementary ventilation plan is feasible.When ventilation loads in upstream and downstream tunnels are imbalanced, the complementary ventilation can be used instead of ventilation shaft in upstream tunnel for large longitudinal slope extra-long tunnel.More>
2014, 14(5): 29-35.
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Transportation vehicle engineering
Control law design of dynamic positioning for ship based on dynamic surface control
DU Jia-lu, YANG Yang, HU Xin, CHEN Hai-quan
Abstract: The control problem of dynamic positioning for surface ship was analyzed, the timevariant environmental disturbances with unknown bounds were considered, the dynamic surface control technology was combined with the vectorial backstepping method, based on which, an adaptive robust nonlinear control law of dynamic positioning was proposed.By introducing the dynamic surface control technique, the proposed control law utilized the differentiation term of the first-order low-pass filter to replace the differentiation term of virtual control vector.As a result, the differentiation operations in the control law design were replaced by the simple algebraic operations.Hence, the control law simplified the computation and was implemented in engineering practice easily.Leakage terms based on a variation of σ-modification were incorporated into the adaptive laws for estimating the unknown bounds of disturbances to prevent parameters from drifting.By using the Lyapunov function, it was proved that the proposed control law could force the ship's position and heading to converge and keep at the desired target values and guarantee the uniformly ultimate boundedness of all signals in the closed-loop dynamic positioning system of ship.Simulation result shows that as the initial horizontal-plane position of ship deviates 25 m from the desired position, the ship can achieve the desired position within 50 sbased on the control law, so the proposed control law is effective.More>
2014, 14(5): 36-42.
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Fuzzy semi-active control of railway vehicle with magnetorheological dampers
LI Zhong-ji, DAI Huan-yun, CENG Jing
Abstract: The control methods of semi-active suspension system for railway vehicle with magnetorheological (MR) dampers were studied.The multi-body dynamics model with 50 freedom degrees of railway vehicle and the Spencer model of MR damper were set up.The fuzzy controller based on the feedback of velocity and acceleration was designed.The inverse model of MR damper predicting the control current was built by using the voltage control function and the separating method of hysteresis characteristic.With the simulation method, the characteristic of fuzzy semi-active suspension system with MR dampers was studied and the dynamics performance of vehicle with semi-active suspension system was analyzed.Simulation result shows that when the fuzzy control method based on the inverse model is used, the actual damping force can track accurately the desired value given by the controller.Compared with the passive suspension system, the fuzzy semi-active suspension with MR dampers can reduce vehicle vibration in the range of 1-10 Hz.When vehicle speed is 250 km·h-1, vehicle vibration acceleration decreases by 53.3%.The riding comfort index increases by 6%-9% when the speed of vehicle ranges from 100 km·h-1 to 300 km·h-1.More>
2014, 14(5): 43-50.
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Dynamic coordinated control method of gear shifting without clutch operation for hybrid electric vehicle
WANG Jun, WANG Qing-nian, WANG Peng-yu, CENG Xiao-hua
Abstract: In order to decrease gear shifting impact, shorten gear shifting time and improve vehicle accelerating performance, a dynamic coordinated control method of gear shifting without clutch operation for hybrid electric vehicle was proposed based on dual-motor hybrid electric powertrain.The driven motor of automatic transmission input shaft was controlled to fast realize rotate speed synchronization in gear shifting process without clutch operation so as to shorten gear shifting time.The driven motor of automatic transmission output shaft was controlled to prevent clutch from over wearing because of frequent separation and combination, and the continuous torque output of driving system was achieved by using motor torque on the output shaft of transmission to reduce the impact degree in gear shifting.Test result shows that vehicle driving force keeps stable in gear shifting because of the dynamic coordinated control method.Compared with the traditional gear shifting method, clutch impact degree reduces by about 60%, and vehicle accelerating performances improve by 5.53% and 5.94% under 0-50 and 0-60 km·h-1accelerating conditions, respectively.More>
2014, 14(5): 51-58.
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Transportation planning and management
Optimal model and improved genetic algorithm of containership stowage on full route
ZHU Hui-ling, JI Ming-jun
Abstract: The stability, strength and load of containership were taken as constraint conditions, the minimum shift and the optimal trim on full route were taken as objective functions, and the multi-objective optimal model of containership stowage on full route was established.The initial feasible solution was obtained by using heuristic algorithm and was optimized by using improved genetic algorithm, and the example verification was carried out on the practical containership with capacity of 1 841 TEU and 3 hatches.Calculation result shows that by using the improved genetic algorithm, the stowage plans of 5 call ports can be obtained within 1.967 s, and the reasonable solution in each port can be obtained compared with traditional genetic algorithm.In the obtained reasonable solutions, all the shift amounts are 0, and the absolute values of trim are 0.003 5, 0.000 8, 0.109 7, 0.001 1 and 0.371 2 mrespectively, which are within a reasonable range between 0 to 0.5 m.For the other routes of call ports with different amounts, the reasonable stowage plan can be highly achieved within 5 s by using the improved genetic algorithm.So, the optimal model and improved genetic algorithm are feasible.More>
2014, 14(5): 59-67.
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Evaluation method of urban expressway service level based on traveling speed index
YANG Fu-she, ZOU Qun, LI Ming, CHEN Kuan-min, GAO Yang
Abstract: According to the characteristics of urban expressway, urban expressway was divided into basic section, weaving section, diverging and merging section.The traveling speed of free flow was calculated by using Greenshields model, and spot speed data were collected through dual-loop detector to estimate traveling speed.After the consistency test of right side mean and mean square deviation for traveling speed index, the service level was quantified, the evaluation method of urban expressway service level based on traveling speed index was proposed, and example verification was carried out on the Southern Section of Second Circular Road of Xi'an City.Evaluation result shows that when the traveling speeds in free flow, peak period and flat peak period are 82.514, 47.825 and 67.930 km·h-1 respectively, the mean and mean square deviation of traveling speed index in peak period are 7.206, 8.482 respectively, and the service level of urban expressway is 2.667 and is Ⅲ level.The mean and mean square deviationof traveling speed index in flat peak period are 6.408, 8.960, and the service level of urban expressway is 4.083 and is Ⅱ level.The calculation result consists with actual situation, so the proposed method is effective.More>
2014, 14(5): 68-73.
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Identification method of dynamic road traffic network vulnerability
ZHANG Yong, TU Ning-wen, TAO Jun-jie
Abstract: The trfffc flow propagation process of section and node and the discrete instantaneous dynamic equilibrium condition of optimal route choice for user were analyzed, the reactive traffic flow model of dynamic user equilibrium network was established, diagonalizable heuristic algorithm was designed to solve the model, and the dynamic vulnerability index of road network was evaluated.Analysis result shows for an example road network with 12 sections and 9 nodes, free-flow speed is 40 km·h-1 and jam density is 125 veh·km-1, when section 1 is broken at time 3, vehicle amount at peak time increases from the original 50 veh to 100 veh at section 3, the inflow of section 3 increases by 1 time, and the inflow of section 2 drops to 0.The damage of section 1 doubles the vehicles on the path consisting of sections 3, 6, 7 and 10, the increase of vehicle amount leads to the increase of impedance on each section.The traffic flow propagation process of vehicle bypassing the broken section can be described, the proposed method is effective to identify the vulnerability of road network for each section at each time.More>
2014, 14(5): 74-81.
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Optimization model of urban parking fare based on equilibrium flow
LIN Zhan, SI Bing-feng, HU Hui, JIANG Ming-qing, YANG Xiao-bao
Abstract: Based on stochastic user equilibrium principle, the route choice and parking choice behaviors of travelers were analyzed, and the urban road parking assignment model meeting the logit relation was set up.Based on the revenue management ideology, the maximum parking revenue was taken as decision target, the bi-level programming model of urban parking fare was set up, and the example verification was carried out by using a small-size network with 7 nodes and 2 parking plots.Analysis result shows that when parking demand is 10 000 pcu·h-1, the parking flow will continue to shift from parking plot 2 to parking plot 1 with the increase of parking fare of plot 2, the parking revenue of parking plot 1 increases unceasing though its fare has no change.The total parking revenue reaches the maximum value when the parking fare of plot 2 is 4 yuan·h-1.When parking demand is 20 000 pcu·h-1, the total parking revenue will continue to increase with the increase of parking fare.On the other hand, the game relation exists betweenthe two parking plots and there is a Nash equilibrium point.In the case of 10 000 pcu·h-1, the optimal fare is 5 yuan·h-1 for the two parking plots, while the optimal fare is ceiling price 10 yuan·h-1 in the case of 20 000 pcu·h-1.More>
2014, 14(5): 82-89.
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Traffic information engineering and control
Interactive evolution between safe headway and control strategy of high-speed trains during following operation
PAN Deng, MEI Meng, ZHENG Ying-ping
Abstract: In order to achieve the safe, effective, and stable operation of high-speed train, the interactive evolution mechanisms between safe headways and control strategies of high-speed trains in given following states were described and analyzed by using Petri net.The calculations of safe headway of high-speed train in complex following states were discussed, and the mathematical model of parking deceleration for high-speed train based on control strategy was established.To satisfy the safety, efficiency and smoothness (comfort) of high-speed train in current following state, the calculation method of safe headway based on control strategies was presented.The calculation method was helpful for real-time calibration of dynamic safe headway and control strategies.In the three following situations that the preceding train was moving at the speeds of 250, 300 and 350 km·h-1 respectively and the speed of following train is 300 km·h-1, the safe headways were calculated when different control strategies were used for preceding and following trains.Calculation result indicates that safe headway varies for different control strategies used for preceding and following trains, and their influences on the behavioral adjustment smoothness (comfort) of following train and the following efficiency are also different.In comprehensive consideration of safety, efficiency and smoothness (comfort) of train following operation, the safe headways in the different following states should be re-calibrated according to different control strategies, and the corresponding database should be established for train operation and control.More>
2014, 14(5): 90-100.
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Overview of research on flight technical error estimation in performance based navigation
ZHAO Hong-sheng, XU Xiao-hao, LI Rui, XIONG Zhi-yong, LI Dong-bin
Abstract: The characteristics and influencing factors of flight technical error (FTE) in performance based navigation (PBN) were analyzed in terms of human factors, aircraft performances and environmental factors.The research and statistical analysis of FTE estimation based on flight experiments were discussed according to navigation schemes and certain operation configurations, and the limitations of the methods were discussed.The estimation models and methods of FTE variance based on moulding mechanism were researched, and the characteristicsand applied ranges of different methods were discussed.The limitations of current researches and expectation of further work were analyzed in terms of FTE estimation method and FTE application.Analysis result indicates that the effect of flying strategy on FTE is prominent when the manual mode is active.Furthermore, lateral FTE is inversely correlated with the sensitivity of course deviation indicator.The standard deviations of lateral FTE for certain general aviation aircrafts are as much as 759.32 and 481.52 m, and the main cause is lack of high-precision onboard navigation system.The FTE estimation method based on fitting flight experiment data has certain limitation because it can not cover all aircraft types, flight segments or weather conditions.The standard deviations of lateral and vertical FTE are 2.68 and 1.13 mrespectively because of using moulding mechanism.The method is proved to be effective through the comparison of both simulation result and test data.The onboard navigation equipment using a certain constant in substitute of real-time FTE estimation will endanger the aircraft.An important research direction in the future is to diminish the FTE in PBN with the consideration of multiple coupled factors.More>
2014, 14(5): 101-110.
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Fusion method of road section average speed based on BP neural network and D-S evidence theory
LI Rui-min, MA Wei
Abstract: In order to estimate road section average speed accurately, a fusion method of road section average speed based on BP neural network and D-S evidence theory was proposed.The values of probability density function were estimated by trained BP neural network, and the data were fused by D-S evidence theory.The self-learning ability of BP neural network and the reasoning ability of D-S evidence theory were combined in the fusion method.The framework and model of the fusion method were presented, and each process of the method was analyzed.The fusion method was verified by using floating car data (FCD), microwave detector data, and license plate recognition data from Beijing-Xizang Expressway.The robustness of the fusion method was verified in the case that microwave detector failed to work.Analysis result indicates that the mean absolute percentage errors of fusion data are 7.90%, 20.72% better than that of FCD and microwave detector data respectively.When microwave detector fail to work, the fusion accuracy reduces, but the errors of fusion data is still smaller than that of FCD, and the fusion method is proved to be robustness.More>
2014, 14(5): 111-118.
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Lane line detection method based on orientation variance Haar feature and hyperbolic model
WANG Hai, CAI Ying-feng, LIN Guo-yu, ZHANG Wei-gong
Abstract: In order to solve the problem that expressway lane lines were easily affected by many factors, which made them hard to be detected, a distributed lane line detection method based on orientation variance Haar feature and hyperbolic model was proposed.In order to get the disappearing line of lane plane in the image, the camera was calibrated firstly.Then, the lower 2/3 zone below the disappearing line was segmented as the region of interestⅠ (ROI-Ⅰ).The dip angle of straight line model of lane line in ROI-Ⅰ was obtained by using edge distribution function.Then the feature points of lane line edge were got by using orientation variance Haar feature, and the straight line model of lane line was fitted.The region of interestⅡ (ROI-Ⅱ) was determined by using the parameters of straight line model.A single direction search algorithm was proposed to get edge feature points.Full lane line model was obtained by using hyperbolic model.The lane line detection method was verified by using about 10 000 actual road images.Verification result indicates that lane line detection in a variety of conditions can beachieved well, the detection rate in fair weather condition is 99.9%, and the detection rate in bad weather condition is 99.7%.More>
2014, 14(5): 119-126.
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