2011 Vol. 11, No. 4

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Design method of warm mix asphalt based on Marshall test under variable temperatures and compaction times
PEI Jian-zhong, XU Li, ZHANG Jiu-peng, XING Xiang-yang
Abstract: In order to establish the mixture design method for warm mix asphalt (WMA), Marshall test was conducted under variable temperatures and compaction times to prepare AC-13C WMA specimens, and the volume characteristics of WMA specimens were researched. Analysis result indicates that the air void volume (VV) and the percent voids in mineral aggregate (VMA) increase with the decrease of compaction temperatures and compaction times, but the percent voids in mineral aggregate that are filled with asphalt (VFA) decrease. Compared with hot mix asphalt (HMA), the asphalt content absorbed by aggregates, the effective asphalt content (mass fraction) and the thickness of asphalt film in WMA differ a little, and the optimum asphalt content of AC-13C WMA is 4.7%. According to the volume characteristics, the compaction temperatures of WMAs are determined, and the compaction temperatures of WMAs with matrix asphalt and SBS modified asphalt decrease by about 10 ℃-20 ℃ and 10 ℃ respectively. WMA compactibility is better, and the compaction times of WMAs with matrix asphalt and SBS modified asphalt decrease by about 20% and 10% respectively.More>
2011, 11(4): 1-9. doi: 10.19818/j.cnki.1671-1637.2011.04.001
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Flexural performance of RC beam strengthened with highstrength steel wire mesh and polymer mortar overlay
LIU Ming, LIU Bo-quan, XING Guo-hua
Abstract: The load-deflection curves of RC beam strengthened with high-strength steel wire mesh and polymer mortar overlay were analyzed, and the bond mechanism between concrete surface and polymer mortar was studied. The overall flexural behaviour of strengthened beam could be divided into precracking stage, cracking stage and failing stage, and an analysis model of section moment and mid-span deflection for RC beam was developed based on plane assumption. The overall flexural behaviour of strengthened beam subjected to concentrated load was analyzed by using transformed section method, and the model was verified by using the test data of 10 strengthened beams. Analysis result shows that the average ratios between the test values and computation values of yielding moment and ultimate moment of beam section are 1.027 and 1.094 respectively, the average ratios between the test values and computation values of yielding mid-span deflection and ultimate mid-span deflection are 1.286 and 0.918 respectively, so the model is feasible.More>
2011, 11(4): 10-16. doi: 10.19818/j.cnki.1671-1637.2011.04.002
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Morphological character of coarse aggregate and its influence on high-temperature shear strength of asphalt mixture
YUAN Jun, QIAN Ye
Abstract: The high-temperature shear strength of asphalt mixture was confirmed by using uniaxial penetration test at 60 ℃. The 2D morphological characters of coarse aggregate were described in terms of shape, angularity and surface texture by using digital image processing technology. The gradation of coarse aggregate was identified based on equivalent ellipse method and sieve size correction factor. The morphological characters of coarse aggregate were extracted by MATLAB, and some characters affecting the high-temperature shear strength of asphalt mixture were proved. Euler number of image in digital topology was applied to quantify the skeleton stability of coarse aggregate. Analysis result shows that the shear strength of asphalt mixture increases due to coarse aggregates with low aspect ratio and eccentricity, high angularity index of equal ellipse perimeter and surface texture parameter. As Euler number decreases, the skeleton structure of coarse aggregate in asphalt mixture with dense framework structure becomes steadier, which leads to higher high-temperature shear strength of asphalt mixture.More>
2011, 11(4): 17-22. doi: 10.19818/j.cnki.1671-1637.2011.04.003
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Comprehensive evaluation method of semi-rigid base mixture's pavement performance
CONG Zhuo-hong, ZHENG Nan-xiang, YAN Hong-guang
Abstract: In order to decrease the evaluation indexes of semi-rigid base mixture's pavement performance and evaluate the performance rationally, a comprehensive evaluation method of pavement performance was presented based on grey correlation clustering analysis, principal component analysis and entropy weight method. The multi indexes were classed according to grey clustering analysis, each cluster was conducted according to principal component analysis, and principal components assemble was decided. The weight of each cluster was decided according to entropy weight method. The comprehensive index was decided to reflect all the indexes' informations and differences. The cement stabilized sandstone mixture's pavement performances of 5 samples as A, B, C, D, E were tested, which were sampled from Sichuan Guangba Expressway. The eleven performance indexes were chosen to evaluate the mixture's performance. Evaluation result shows that the order from superior to inferior of pavement perfromances is as follows A, B, D, C, E, and the result is consistent with the evalutation result of grey correlation degree, so the comprehensive evaluation method is easier to differentiate the mixtures' performances.More>
2011, 11(4): 23-28. doi: 10.19818/j.cnki.1671-1637.2011.04.004
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Static and dynamic properties of three-tower suspension bridge and structural type selection of mid-tower
LIANG Peng, WU Xiang-nan, LI Wan-heng, XU Yue
Abstract: In order to discuss the static and dynamic properties differences between three-tower and two-tower suspension bridges, and select the rational structure type of mid-tower, based on the Taizhou Yangtze River Bridge, the 3D space finite element models of two-tower suspension bridge and three-tower suspension bridges with concrete mid-tower and steel mid-tower were set up by finite displacement theory and the static and seismal effects were analyzed under various structural parameters. Analysis result shows that compared with two-tower suspension bridge, because the mid-tower is lack of effective restraints from side cables, three-tower suspension bridge has lower total stiffness, lower natural frequency and larger deflection-to-span ratio of main girder. Under vehicle loads, the anti-slipping safety factor between main cable and saddle, the forces of mid-tower and the deflection-to-span ratio of main girder are not important for two-tower suspension bridge, but become controlling indices for three-tower suspension bridge. The indices are related to the anti-pushing rigidity of mid-tower, but have incompatible demands for the rigidity. Under vehicle loads, when the steel mid-tower with upside-down Y shape is selected, the anti-slipping safety factor between main cable and saddle of mid-tower is 2.17, the maximum stress of mid-tower is 182 MPa, the deflection-to-span ratio of main girder is 1/210, and they meet correlative demands. Obviously, due to the application of steel mid-tower, the indices are rationally considered, the stiffness optimization of components and cable system is achieved, so, it is an appropriate structure for mid-tower.More>
2011, 11(4): 29-35. doi: 10.19818/j.cnki.1671-1637.2011.04.005
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Wheel/rail force continuous exporting algorithm of instrumented rail
LI Yi-fan, LIU Jian-xin, WANG Kai-yun, LIN Jian-hui, WANG Chao-feng
Abstract: According to wheel/rail interaction characteristics, ground test data were used, and the available data of wheel/rail force were extracted by using threshold value judgmental method. An algorithm based on radial basic function neural network(RBFNN) was designed to deal with the nonlinear relationship of wheel/rail forces at different measure points, and the neural network was trained by lateral and vertical forces at different contact points of different wheels. The wheel/rail force continuous measurement of instrumented rail was achieved, and the simulation experiments under three working conditions were conducted. Analysis result indicates that the accuracy of continuous wheel/rail force when both interference and strain gage damage exist is lower than that when interference or part strain gage damage exists respectively. The algorithm can real-timely process wheel/rail force signal when sampling frequency is less than 8 720. 9 Hz, and has good applicability.More>
2011, 11(4): 36-40. doi: 10.19818/j.cnki.1671-1637.2011.04.006
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Coupled vibration analysis of flexible car body and bogie for high-speed train
GONG Dao, ZHOU Jing-song, SUN Wen-jing, XIE Wei-da
Abstract: A finite element model of car body for a high-speed train was built, and the modal parameters were calculated by using Guyan reduction method. A system dynamics model including flexible car body was established by using multi-body dynamics software SIMPACK. The influence of car body elastic mode on riding quality was analyzed based on the model, and the vertical coupled vibration between flexible car body and bogie frame was studied. Analysis result shows that when the first vertical bending frequency of car body closes to the null nod response frequency of car body, the vertical flexible resonance of car body will happen. When the diagonal distortion frequency is higher than 9 Hz, and first vertical bending frequency is higher than 10 Hz, car body flexibility almost has no effect on riding quality. The primary suspension vertical stiffness of bogie for the train matches with the first vertical bending frequency of car body, even if frame bounce and nod frequencies coincide with the first vertical bending frequency, there will not have the flexible resonance of car body and bogie.More>
2011, 11(4): 41-47. doi: 10.19818/j.cnki.1671-1637.2011.04.007
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Running attitudes of car body and wheelset for high-speed train under cross wind
YU Meng-ge, ZHANG Ji-ye, ZHANG Wei-hua
Abstract: The aerodynamics model of high-speed train was established by using fluid dynamics theory, and the aerodynamic forces and aerodynamic moments acting on the car body of high-speed train were calculated. Vehicle system dynamics model was established by using multi-body dynamics theory, and the running attitudes of front car body and wheelset for high-speed train under different wind directions, side slip angles and synthetic wind speeds were analyzed. Calculation result indicates that under different cross wind conditions, front car body always traverses and rolls toward the leeward side. When wind direction is 90°, the lateral displacement and roll angle of front car body always are biggest. When train speed is 350 km·h-1, cross wind speeds are 13.8, 32.6 m·s-1 respectively, the maximum lateral displacements of car body are 74. 2, 171. 7 mm respectively, and the maximum rolling angles are 3.1° and 8.4° respectively. When train speed is 200 km·h-1, cross wind speed is more than 32.6 m·s-1, and wind direction is 90°, the first and second wheelsets of front car traverse toward the leeward side, and the wheels on the leeward side have climbing track phenomenon. The third and fourth wheelsets traverse toward the windward side, and on the windward side, the third wheelset has climbing track phenomenon. The lateral displacement and yaw angle of the fourth wheelset are less than those of former three wheelsets, and the fourth wheelset is relatively safe.More>
2011, 11(4): 48-55. doi: 10.19818/j.cnki.1671-1637.2011.04.008
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Simulation of wheel wear for heavy haul freight car
DING Jun-jun, SUN Shu-lei, LI Fei, HUANG Yun-hua
Abstract: The dynamic model of C80 heavy haul freight car with ZK6 bogies was built in SIMPACK software, LM wheel profile and 75 kgºm-1 rail profile were matched, and a railway line model was built based on Daqin Railway Line. The wheel wear of heavy haul freight car was simulated based on FASTSIM algorithm and Zobory tread wear model, and the simulation results were compared with that of field test result. Analysis result indicates that wear occurs in-50-45 mm of wheel tread, the maximum wear depth occurs in wheel flange, and the minimum wear depth occurs in wheel flange root. The wear velocities of wheel flange and rolling tread circle slow with the increase of running mileage. The vertical wear depth of wheel tread in simulation is less than test depth. The critical velocity of vehicle decreases when wheel is worn, the critical velocity of empty vehicle deceases by 13-18 kmºh-1, and the critical velocity of loaded vehicle deceases by 2-8 kmºh-1.More>
2011, 11(4): 56-60. doi: 10.19818/j.cnki.1671-1637.2011.04.009
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Pneumatic electronic assistant brake device based on high-speed on/off valve
WANG Jian-qiang, YANG Bo, LI Sheng-bo, LI Ke-qiang
Abstract: In order to satisfy the demands of automatic braking in longitudinal driving assistance systems for commercial vehicles, a pneumatic electronic assistant brake device was developed based on high-speed on/off valves. Its mathematical model was built, and a PI controller with resistance integral saturation was designed. High-speed on/off valves were regulated dynamically by using pulse width modulation method, and the brake pressure of vehicle was controlled actively. The hardware-in-the-loop platform of pneumatic electronic assistant brake device was developed, and its control performance was verified. Analysis result shows that the device can respond to brake command fast and accurately, its stable error and response time are less than 0.01 MPa and 0.3 s respectively. While it is easy to be fixed, and has good compatibility with the braking system of commercial vehicle.More>
2011, 11(4): 61-67. doi: 10.19818/j.cnki.1671-1637.2011.04.010
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Optimization algorithm of branch transportation route for container ship
JI Ming-jun, CHEN Zhe, WANG Qing-bin
Abstract: On the basis of the limit time of hub port ship and branch ship capacity, hub-and-spoke network transportation model was analyzed. Taking the total minimum navigation time of ship as objective function, the mixed integer programming model of branch container transportation model was set up. Hybridization and variation were realized by designing itinerant route method, the structure of solution was updated, and genetic algorithm was used to solve the model. Calculation result indicates that when ship capacity is 150 TEU, the total navigation time is 708.6 h, and the route number is 8 after 160 times iteration. When the ship capacities are 100 and 150 TEU respectively, the total navigation time is 714.6 h, and the route number is 9 after 150 times iteration. Through the variance analysis of the limit time of hub port ship and branch ship capacity, the probability values of F test statistics are almost less than 0.05 significantly. Through the sensitivity analysis of branch ship capacity and running cost, while there is higher ship capacity, there are lower route number and navigation time, but there is higher running cost. When there is the bigger limit time of hub port ship, there is lower route number. While considering navigation time and running cost, the ship capacity of 150 TEU is most reasonable.More>
2011, 11(4): 68-75. doi: 10.19818/j.cnki.1671-1637.2011.04.011
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Clustering and discrimination of port function in China
HUANG Shun-quan, QU Lin-chi, YU Si-qin
Abstract: According to the sample characteristics of ports in China, 11 major function indexes were selected, factor analysis model was established, and suitability test was carried out. On the basis of principal component analysis, three factors were extracted. By using factor rotation and normalization, the major functions of 24 seaports in China were clustered based on system coagulation method. The functional category of Yantai Port was discriminated by using MATLAB. Analysis result shows that based on the classifications of economic function factor, urban function factor and logistics function factor, 24 seaports in China can be clustered into 7 categories. The first class port is Shanghai Port, the second class port is Shenzhen Port, the third class port is Guangzhou Port, and the forth class port is Ningbo-Zhoushan Port. The fifth class ports are Qingdao Port, Tianjin Port and Dalian Port. The sixth class ports are Xiamen Port, Dandong Port, Weihai Port, Shantou Port, Beihai Port, Fangcheng Port, Haikou Port, Lianyungang Port, Yingkou Port, Qinhuangdao Port and Rizhao Port. The seventh class ports are Tangshan Port, Wenzhou Port, Taizhou Port, Fuzhou Port, Quanzhou Port and Zhanjiang Port. Then Yantai Port is identified into the seventh class by using artificial neural network method. So, the method is effective.More>
2011, 11(4): 76-83. doi: 10.19818/j.cnki.1671-1637.2011.04.012
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Multi-objective optimization model and ant colony optimization of liner ship scheduling
SHOU Yong-yi, LAI Chang-tao, LU: Ru-fu
Abstract: Aiming at liner ship scheduling problem, on the basis of rational allocation for liner ships to different round trips and non-existing time conflict, the minimum variation cost on liner ship, the minimum carrying amount notch on route and the absolute minimum deviation of total liner voyages were taken as objective functions, a time-space network was constructed based on port periods and round liners, and a 0-1 integer programming mathematical model was established. The historical data of a certain liner shipping company were analyzed, ant colony optimization was used to solve the model, and a neighborhood search technique was integrated to raise the efficiency. Calculation result shows that while the carrying amount can meet the running requirement, the daily liner variation cost of liner running decreases from 198 086.3 yuan to 170 472.2 yuan, and decreases by about 13.9%. The absolute deviation of total liner voyages decreases from 4.4 times to 2.2 times, and decreases by about 45. 5%, and liner utilization ratio is more equilibrium. Obviously, the proposed model is feasible, and the algorithm is effective.More>
2011, 11(4): 84-88. doi: 10.19818/j.cnki.1671-1637.2011.04.013
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Decision support system of track utilization with CTC at railway passenger station
ZHANG Ying-gui, LEI Ding-you, WANG Juan
Abstract: With station autonomy machine, interlocking system, various technological operations and their requirements of track utilization at railway passenger station, the system model, functions and structure were designed based on the principle of decentralized and self-regulated control. The real-time adjustment controllable scheduling model and coupled model of track utilization were constructed by utilizing modern scheduling theory. The three-step algorithm of synthesis dispatching rules and the general heuristic algorithm of track utilization were put forward to solve the series decision problems of track utilization and disturbance problems among technical and shunting operations. A decision support system of track utilization with centralized traffic control (CTC) at railway passenger stations was developed. Analysis result indicates that the means optimum solution of synthesis dispatching rules is much better than that of basic dispatching rules, and the synthesis dispatching rule EDD+FIFO can get the best solution. The synthesis dispatching rules, especially EDD+FIFO, should be adopted to make real-time adjustment plan, while various dispatching rules should be applied to solve track utilization coupled problem. So the system functions, performances and technical parameters can meet the practical needs for making track utilization plan and real-time adjustment plan at railway passenger station intelligently.More>
2011, 11(4): 89-96. doi: 10.19818/j.cnki.1671-1637.2011.04.014
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Identification method of road hot zone based on GIS
LOO B P Y, YAO Shen-jun, WU Jian-ping, YU Bo-lang, ZHONG Hai-dong
Abstract: Based on GIS and the basic model of hot zone, the identification method of road hot zone was studied. Road networks were merged by following a priority sequence, and the basic spatial units (BSU) of road were obtained. The spatial distribution of traffic accidents was simulated, and the threshold value of traffic accident for each BSU was defined by using Monte Carlo method. The spatial contiguities of BSUs were examined to obtain hot zones, and the hot zones around Shanghai Expo Venue were identified. Analysis result shows that the share of irregular BSUs decreases from 41.5% to 14.8% after merging road networks. There are 84 hot zones involving only vehicles and 33 hot zones involving pedestrians, which accords with the real situation. So the method can effectively identify road hazardous locations.More>
2011, 11(4): 97-102. doi: 10.19818/j.cnki.1671-1637.2011.04.015
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Optimization method of phase difference for urban traffic arterial control system
LU: Bin, NIU Hui-min
Abstract: Based on the random distribution characteristic of link travel speed, the limitations of phase difference optimization methods for the existed arterial control systems were analyzed. Link travel time, vehicle delay and queue length were taken as evaluation indexes, the phase difference optimization algorithm of arterial control system was designed by using information entropy theory and multi-attribute synthetic decision method, and a simulation calculation was carried out. Calculation result indicates that when the variance of link travel speed increases from 5 km·h-1 to 10 km·h-1, link travel speed, vehicle delay and queue length of west-to-east traffic flow increase from 98.4 s, 13.5 s·pcu-1 and 9.1 pcu to 115.5 s, 15.9 s·pcu-1 and 12.3 pcu respectively. Link travel speed, vehicle delay and queue length of east-to-west traffic flow increase from 99.4 s, 13.5 s·pcu-1 and 9.2 pcu to 108.7 s, 14.3 s·pcu-1 and 10.8 pcu respectively. So, the random distribution characteristic of link travel speed has an obvious effect on settings of phase difference, and the optimal phase difference can be obtained by using the proposed model.More>
2011, 11(4): 103-107. doi: 10.19818/j.cnki.1671-1637.2011.04.016
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Traffic control method of highway tunnel emergency based on CBR and RBR
LIN Shan, XU Hong-ke, LIU Zhan-wen, LI Shu-guang
Abstract: On the basis of traditional traffic control methods concluded by using experiences in highway tunnel, a traffic control method of highway tunnel emergency combining case-based reasoning (CBR) and rule-based reasoning (RBR) was provided by utilizing knowledge expression methods and rule-based expert system. A response plan generation and management system for highway tunnel vehicle guidance under emergency was set up based on the method. A parallel separate expressway tunnel was taken as example, cases were expressed as a triple-tuple form by using object-oriented expression method, including case attribution information, control scheme information and result information, and case similarity computation method was discussed. IF-THEN expression method was used, and the class attribute of highway tunnel emergency and the attribute of blocked lane numbers were combined, the reasoning rules of vehicle diffluence control strategy for single point traffic accident were produced. Simulation result shows that when the case number is insufficient, the traffic control method can reduce the generation time of response plan by 22% compared with CBR approach, and the method is efficacious.More>
2011, 11(4): 108-113. doi: 10.19818/j.cnki.1671-1637.2011.04.017
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Test case generation method of radio block center
GOU Chen-xi, CAI Bo-gen, TANG Tao, SHANGGUAN Wei
Abstract: Test case generation method based on function features was used, the function structure of radio block center (RBC) was studied, the function features of RBC were extracted, and the feature list of RBC was obtained. Aiming at the each feature of RBC, test cases were compiled and serially combined to electronic test sequence. On the basis of standards and requirements of running control system for China high-speed train, RBC test platform was established, and test step and XML program document was written. With RBC test platform, the three test sequences of five running features containing registration and start-up, driving permission, parking and cancellation, communication network fault and RBC switching. Test result shows that under room temperature and atmospheric pressure, while there is only one train and its speed is less than 350 km·h-1, the uninterrupted working time of RBC is more than 90 min, and the function can be kept well. So, the proposed method is effective.More>
2011, 11(4): 114-122. doi: 10.19818/j.cnki.1671-1637.2011.04.018
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Shortest path improved algorithm based on GIS under large-scale disaster
YU De-xin, YANG Wei, YANG Zhao-sheng
Abstract: The Dijkstra algorithm under large-scale disaster was improved by using classical Dijkstra algorithm, and the function of penalty factor was built. Complex network analysis function was realized by using Visual C++ 6.0 and the secondary development module of GIS. The impacts of node quantity on road reliability and the selection of optimal path under large-scale disaster were analyzed. Distance, travel time and node quantity were considered, the advantage of improved Dijkstra algorithm in the selection of optimal path was proved. Analysis result shows that the node quantities computed by improved Dijkstra algorithm and classical Dijkstra algorithm are 31, 59 respectively, travel times are almost same. So the improved algorithm can reduce the node quantity in evacuation route effectively, and decrease the delay loss and risk of vehicle at the node.More>
2011, 11(4): 123-126. doi: 10.19818/j.cnki.1671-1637.2011.04.019
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