2010 Vol. 10, No. 4

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Analysis of mechanics response for climbing section of asphalt pavement under moving load
PEI Jian-zhong, CHEN Yong, ZHANG Jiu-peng, BI Yu-feng
Abstract: Jiefang CA141 was selected as a representative vehicle, the four possible kinds of driving behaviors at climbing section were analyzed, and the acceleration was calculated based on the parameters of dynamics performance when vehicle shifted to accelerate or decelerate at climbing section.A 3D finite element model was established for the transient dynamics analysis of asphalt pavement under moving load.The compressive stresses, shear stresses and vertical displacement characteristics under different driving behaviors were analyzed.Calculation result shows that under the effect of moving load, the mechanics response of pavement structure not only has fluctuation, but also presents alternating feature within a certain region, and there is reversal of changes on tension and compression stresses in the area.Specifically, compressive stress concentrates in the area of 0~6 cm for road surface, the maximum shear stress moves from wheel joint to wheel centre as the speed of vehicle reduces and the horizontal force increases, and its peak shifts from middle surface layer to road surface along depth direction.The speed variation and low speed are the main reasons for pavement rutting at climbing section.More>
2010, 10(4): 1-7. doi: 10.19818/j.cnki.1671-1637.2010.04.001
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Calculating methods of stress for cement concrete pavement slab under plane loads
ZHENG Fei, WENG Xing-zhong
Abstract: With elastic base theory, the main influence factors of stress for pavement slab under plane loads were analyzed, the calculating formula form of stress was deduced by modifying the stress formula of highway pavement under standard axis load.Pavement's structural parameters were organized by orthogonal design method, and the stresses under different combinations of plane loads and pavement structures were calculated by FEM.The stresses and parameters were analyzed by nonlinear regression method, and the calculating formulae of stress under single wheel plane load were got.By introducing the modifying coefficient of load radius, the calculating formulae of stress under dual-wheel and dual-wheel-dual-axes plane loads were deduced by nonlinear regression method.The calculating formulae of stress under multi-wheel-multi-axes loads were deduced by combined load theory.Error analysis result indicates that the relative errors between the calculating results by nonlinear regression method and FEM are less than 2%, so the stress formulae have high precision.More>
2010, 10(4): 8-15. doi: 10.19818/j.cnki.1671-1637.2010.04.002
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Evaluation method of pavement roughness based on 5-DOF human-vehicle-road vibration model
ZHANG Hong-liang, YANG Wan-qiao
Abstract: To evaluate the riding comfort of pavement, human-vehicle-road interaction was analyzed by using transfer matrix method, in which the vertical weighted root-mean-square(RMS)acceleration of passenger was adopted as the evaluation index of pavement roughness, a 5-DOF vibration model was used, and the coupled interaction between vehicle and road was considered.The effects of running speed, rotary inertia of vehicle body, spring constant and damping constant of seat, and spring constant of tire on RMS were discussed, an evaluation method of pavement roughness based on human-vehicle-road interaction was proposed and an example was given.The RMS accelerations of the pavements graded A, B, C and D were 0.381 2, 0.796 3, 1.232 0 and 2.970 6 m·s-2 respectively, and the ratings of riding comfort of the pavements were correspondent with their subjective ratings.Compared with the existing evaluation methods of pavement roughness, the evaluation method considers the impacts of pavement types and vehicle speeds, reflects the impact of rotating of vehicle, and can evaluate the riding comfort of truck.More>
2010, 10(4): 16-22. doi: 10.19818/j.cnki.1671-1637.2010.04.003
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Deck roughness evaluation of concrete-filled steel tubular arch bridge
WU Qing-xiong, CHEN Bao-chun
Abstract: The deck roughness of Tongshan Bridge in Fuding was measured by using leveler and laser continuous pavement profilometer respectively.Maximum entropy method(MEM)for the spectrum analysis of deck roughness was adopted, and the advantage of laser continuous pavement profilometer was obtained.The deck roughnesses of several concrete-filled steel tubular(CFST)arch bridges were collected and analyzed, and the presented relationship between two main methods, which are power spectral density(PSD)method and international roughness index(IRI)method, was configured.The deck roughnesses were evaluated from main beam type, main span of arch and service years.It is found that IRI value with exponential form increases following service years.Therefore, the relationship between deck roughness and service years is presented, which can simply predict the deck condition of CFST arch bridge.More>
2010, 10(4): 23-28. doi: 10.19818/j.cnki.1671-1637.2010.04.004
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Influence range calculation of damaged bridge during vibropile construction
FENG Zhong-ju, WU Yan-ling, CHENG Chao, WU Ming-yuan
Abstract: The influence range of damaged bridge during vibropile construction on surrounding soil was studied in the actual accident scene of Jiujiang Bridge by using vibration theory, cavity expansion theory and simulation analysis.The lateral displacement of foundation soil under vibration load was simulated, and the influence range was 20 m according to the diminish law of displacement.According to vibration theory, the attenuation of vibration wave in foundation soil was considered, and the influence range was 15 m.Using cavity expansion theory, the relationship between the aperture and the plastic zone for the soil was analyzed, and the influence range was 23 m.The influence ranges were between 15 m and 23 m.The factors such as piling rate, piling order and piling process were considered under the construction, according to the theoretical computation results, the processing scheme of actual project and measure result, the intended safe distance is 18 m.Applied result shows that the vibration wave caused by the construction of accident treatment platform's vibropile foundation, does not cause further collapse in surrounding environment, so the influence range of theoretical analysis is scientific and reasonable.More>
2010, 10(4): 29-33. doi: 10.19818/j.cnki.1671-1637.2010.04.005
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Risk assessment and control measures of collapse for tunnel construction
WANG Hua-lao, LI Ning, WANG Hao
Abstract: In order to prevent tunnel collapse and optimize tunnel design before tunnel construction, the collapse risk of Wolonggang Tunnel was taken as research object, the safety of tunnel primary shoring was analyzed, the risk factors of tunnel collapse were cleared, risk sources were identified combined with tunnel geology conditions, and analytic hierarchy process was used to rank the importantces of risk resources.The probability grades and risk loss grades were confirmed through expert investigation, and the grades of collapse risk were given by using risk matrix technique.Analysis result indicates that tunnel collapse inducements include the prompt closing of primary shoring, the removing occasion of temporary timbering, the close following of secondary lining and blasting concussion.The collapse risk grade of Wolonggang Tunnel is grade Ⅲ and is higher.More>
2010, 10(4): 34-38. doi: 10.19818/j.cnki.1671-1637.2010.04.006
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Influence of transition curves on dynamics performance of railway vehicle
ZHANG Jian-quan, HUANG Yun-hua, LI Fei
Abstract: The action forces of vehicle on transition curves were analyzed.The calculated dynamics performances of heavy haul wagon with 25 t axle load were analyzed by using dynamics simulation software SIMPACK while passing through cubic parabola type, 4-3-4 type and quintic type transition curves.The calculated result was compared with the theoretical analysis one.The result indicates that the types of transition curves have great effect on the dynamics performance of vehicle, especially at connection point.Compared with 4-3-4 type and quintic type, the dynamic performance of vehicle at connection point is worse while running on quintic type transition curve, the differences of carbody vertical accelerations reach 83%, and the differences of other indexes are about 10%.The difference of carbody vertical accelerations between 4-3-4 type and quintic type is 63%, and the differences of other indexes are less than 2%.4-3-4 type and quintic type transition curves will have more advantages if the curves are prolonged.More>
2010, 10(4): 39-44. doi: 10.19818/j.cnki.1671-1637.2010.04.007
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Hydrodynamic layout of strongly maneuvering underwater supercavitating vehicle
LUO Kai, LI Dai-jin, QIN Kan, DANG Jian-jun, WANG Yu-cai
Abstract: A novel hydrodynamic layout based on anisomerous bow rudder was firstly proposed for strongly maneuvering underwater supercavitating vehicle because aft rudder is short of effectiveness.In the layout, straight-and-level flight and strong maneuverability motion were considered.Bow rudder with 2 DOFs controlled orientation with deflexion in level, and controlled pitching or depth with up-and-down motion.Anti-roll fin appended below the rudder generated imbalances torque.For validating the dynamic characteristic of the design layout, related simulation on a supercavitating vehicle was carried out.The attenuation of remanent roll moment completes in about 0.1 s, and ultimate roll angle is less than 0.1°.Analytical result shows that the novel layout can markedly improve control rudder effectiveness.More>
2010, 10(4): 45-49. doi: 10.19818/j.cnki.1671-1637.2010.04.008
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Constant air gap control simulation of linear induction motor of metro vehicle
LUO Ren, WU Ping-bo, LIU Bin-bin
Abstract: In order to research the influence of suspension types of linear induction motor(LIM)on the dynamics performance of vehicle system, and further decrease the air gap fluctuation of LIM and reduce wheel-rail impact by using active suspension, the multi-body dynamics model of metro vehicle was set up.The electromagnetic force model of LIM was built by using classical electromagnetic theory.The model of constant air gap control system with electromechanical actuator was established.The constant air gap control strategy and its influence on the vehicle's dynamics were studied by numerical simulation.Simulation result shows that the air gap change is mainly caused by the change of load when large-deflection primary suspension and LIM frame suspension are adopted, its frequency is very low, so the constant air gap control of LIM is easy to carry out.The control can guarantee that the vehicle meets the requirement of air gap under different load conditions, vertical wheel-rail interaction force reduces by about 10 kN, and the comfort index decreases by about 0.1.Moreover, the dynamics performance of the vehicle will be improved campared with traditional LIM vehicle, and its traction force is smoother.More>
2010, 10(4): 50-57. doi: 10.19818/j.cnki.1671-1637.2010.04.009
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Simulation of human vibration characteristics based on 9-DOF riding dynamics model
ZHANG E, LIU Zhong-hua, SHAO Xiao-chun
Abstract: To predict the human vibration response characteristics and riding comfort of human-vehicle system efficiently, a 9-DOF riding dynamics model of automobile was established according to human-vehicle-road interaction and multi-body dynamics principle.The dynamics equations of the model were derived by using Lagrange Principle.A time domain model of random road excitation was established according to random road excitation and the change of vehicle speed.A human-vehicle-road system simulation model was established by using MATLAB/Simulink, and the simulation and analysis of human vibration response in a light vehicle on different roads and at different speeds were carried out.Simulation result shows that the amplitude of human acceleration response significantly increases with the drop of road level at the same speed.On random road, the energy of human vibration caused by random road excition concentrates in low frequency, the first order resonance frequency appears around 5 Hz, and the second order resonance frequency occurs around 10 Hz, which is consistent with many experimental results.Therefore, the 9-DOF dynamics model and the simulation model are reliable to quickly compute the vibration characteristics of human and riding comfort under dynamic environment.More>
2010, 10(4): 58-64. doi: 10.19818/j.cnki.1671-1637.2010.04.010
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Characteristic analysis of basic unit and complex network for urban rail transit
MA Jia-qi, BAI Yan, HAN Bao-ming
Abstract: The characteristics of urban rail network were comprehensively studied from part and overall perspectives.From part perspective, the 2-line, 3-line and 4-line basic units of urban rail transit network were analyzed.Indicators such as transfer times, coverage intensity of attraction zone and load of transfer station were proposed to evaluate each basic unit.From overall perspective, complex network theory was used, and in topological Space P, indicators such as the degree, clustering coefficient of node and average path length were proposed to characterize overall network, and network characteristics were understood from topological network.Analysis result shows that the basic units of urban rail transit network are radiation, cross and ring.Triangle with ring, triangle with triangle and multiple triangles are relatively ideal complex forms.In the urban rail network of Beijing, with the increase of node degree, its probability distribution follows the trend of first increasing and then decreasing.The clustering coefficients of many stations are 1, and travels with no more than one time transfer are more than 80%, so the current rail network of Beijing is comparatively convenient.More>
2010, 10(4): 65-70. doi: 10.19818/j.cnki.1671-1637.2010.04.011
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Spacing calculation and selection on opposite vehicle access of large public building
ZHUO Xi, ZHANG Ning, QIAN Zhen-dong
Abstract: To reduce crash rate, the access management(AM)strategy was considered, and opposite vehicle access features of large public buildings were analyzed.A minimum opposite access spacing model was established based on microscopic traffic flow theory, and its optimization objective was to eliminate conflicts due to inadequate spacing.The maximum spacing was deduced to keep access from the functional area of intersections, and a spacing range was formed, traffic simulation and entropy weight method were utilized, and the technique for order preference by similarity to ideal solution(TOPSIS)based on traffic conflict techniques was proposed to evaluate the spacing schemes and search the optimal spacing from several spacing values.A large public building area was taken as an example for spacing calculation and selection.Calculation result indicates that the range of opposite access spacing is 83.98~278.76 m, its optimum spacing is 120.73 m, and the closeness degree of optimal solution is 0.518 2.When spacing value is in the range, there is a miximum value of closeness degree.More>
2010, 10(4): 71-78. doi: 10.19818/j.cnki.1671-1637.2010.04.012
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Capacity of exclusive dual left-turn lanes at signalized intersection
SHAO Chang-qiao, RONG Jian
Abstract: Based on the survey data of six signalized intersections with dual left-turn lanes in Beijing, the saturation time-headways, saturation flow rates and their influencing factors of dual left-turn lanes at signalized intersections were studied by using statistical methods.By comparing with arithmetic mean value and median value, the trimmed mean value method was used to calculate the saturation time-headway and saturation flow rate.The effects of lane width and turning radius on the saturation flow rate were studied, and the regression model of saturation flow rate with turning radius was suggested.The saturation flow rates of inside lane, outside lane and single left-turn lane were compared.Analysis result shows that the saturation time-headway of inside lane is 2.14~2.60 s, the saturation time-headway of outside lane is 2.08~2.37 s, and the average saturation flow rate is 1 600 pcu·(h·lane)-1.The ratio of sum saturation flow rate of inside lane and outside lane to that of single left-turn lane is 1.80~2.05.More>
2010, 10(4): 79-84. doi: 10.19818/j.cnki.1671-1637.2010.04.013
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Research status and prospect of fleet planning
YANG Qiu-ping, XIE Xin-lian, ZHAO Jia-bao
Abstract: In order to promote the studies in the area of optimizing fleet development strategy, the core task and basic goal of fleet planning were analyzed, and the research progress was concluded.The research methods applied to fleet planning problems were reviewed and divided into linear programming, integer programming, dynamic programming, simulation technology and other methods.The research emphases and directions of fleet planning in the future were indicated.Analysis result shows that the previous researches on fleet planning for mass industrial material shipping have gotten a lot of achievements, the object of future research should focus on container liner shipping and tramp shipping, and the future research focus should be the development of new optimization models and algorithms.The problems of fleet planning under uncertain condition will be the direction of future research, and the application of decision support system for fleet planning must be a development trend for shipping industry in the future.More>
2010, 10(4): 85-90. doi: 10.19818/j.cnki.1671-1637.2010.04.014
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Impact of rail transit on price increase of residential real estate
MA Chao-qun, YANG Fu-she, WANG Yu-ping, LI Xue-jun
Abstract: The internal mechanism and contributory factors on the impact of rail transit on the price of residential real estate alongside rail transit were analyzed, and a quantitative model was proposed to measure the influence based on Alonso's Residential Location Theory.In this model, the lowest living costs of residents were taken as equilibrium condition, housing costs and trip costs were exchanged, and their differences of defraying times were taken into account.The price increase of residential real estate caused by rail transit operation was measured by using income capitalization approach, and the proposed model was used in Xi'an Metro Line 2.Calculation result shows that the longer the distance from urban center is, the higher the price increase of residential real estate alongside rail transit is, and the impact of Xi'an Metro Line 2 on the price increase of real estate is 10% averagely.More>
2010, 10(4): 91-96. doi: 10.19818/j.cnki.1671-1637.2010.04.015
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Longitudinal evaluation of highway construction effectiveness based on DEA
ZHANG Chun-mei, MA Zhan-xin
Abstract: The C2R and C2GS2 models of DEA method were used, the decision-making units of evaluation were 9 years from 2000 to 2008 in Inner Mongdia, and the input and output indicators of highway construction were put forward.The overall effectiveness, technical efficiency and projection measure of highway construction were evaluated by appropriate DEA method, and efficiency improvement measure was proposed.Analysis result shows that the inputs and outputs of highway construction in Inner Mongolia are best in 2004 and 2008, and their overall effectivenesses are valid.In other years, there are increasing returns to scale, and increasing investments can get better output.Technical efficiencies are invalid in 2003, 2006 and 2007, highway construction management need be enhanced while the investment is increasing, and the introduction and application of new technology should be emphasized in Inner Mongolia.More>
2010, 10(4): 97-102. doi: 10.19818/j.cnki.1671-1637.2010.04.016
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EHPN-based modeling of airport taxiway operation control in A-SMGCS
ZHU Xin-ping, TANG Xin-min, HAN Song-chen
Abstract: For the modeling of taxiway operation control in advanced surface movement guidance and control system (A-SMGCS), an extended hierarchical Petri net (EHPN)-based method was proposed.The taxiway system was divided into intersection and line segment modules.Aircraft behaviors in the two modules were encapsulated, and extended Petri net (EPN)-based generic modules were formed.The process layer model was constructed by using synchronizing composition techniques.An agent-oriented colored time Petri net (AOKCTPN) modeling approach was used to establish generic decision-making module.The operation control knowledge of taxiway was integrated into places and transitions, and the intelligent decision-making ability of decision-making layer model was enhanced.The taxiway operation data of some airport in 12 h were used to conduct simulation.Analysis result indicates that the conflict numbers in taxiway line segment and intersection are 6 and 11 respectively, and the total delay of taxiway system is 346 s.The result is relatively consistent with that of SIMMOD model, so the EHPN-based method is feasible.More>
2010, 10(4): 103-108. doi: 10.19818/j.cnki.1671-1637.2010.04.017
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Airport delay performance evaluation based on fuzzy linear regression model
ZHANG Jing, XU Xiao-hao, WANG Fei, WEI Dong-xuan
Abstract: In order to effectively evaluate the delay performance of airport, taking into account that the weather and traffic variable values were usually subject to some uncertainty factors, the features of traffic demand and weather were used to develop a fuzzy linear regression model for airport arrival delay, and the estimated delay was computed.The continuous baseline to measure operational airport delay performance was obtained by comparing estimated delay with actual delay.The delay performance could be evaluated based on the delay baseline.Analysis result indicates that the features of traffic demand and weather have a strong linear relationship with airport arrival delay, which can be fitted with the model.The delay performance baseline takes into account the impact of airport weather and traffic demand on the delay, and divides the delay into low, medium and high levels, and the delays of different days can be compared and evaluated.More>
2010, 10(4): 109-114. doi: 10.19818/j.cnki.1671-1637.2010.04.018
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Perception model of driver spatial vision in traffic simulation
ZHANG Chi, YANG Shao-wei, PAN Bing-hong, ZHAO Yi-fei
Abstract: The movement rule of drivers' visual gaze points was analyzed, the horizontal visual angle of spatial vision range was studied, the relationship among speed, vision and gaze distance was established, and a perception model of driver spatial vision was proposed.According to the 3D coordinate equations of road centerline and parallel, a calculation method of spatial vision perception model was put forward.In order to test and verify the model, 5 participants carried out four different tests to obtain 722 combination data and 3 585 speed data through simulating actual scene.Study result shows that the coincidence rate between prediction result and experimental result is more than 70%, the unconspicuous effect rate is less than 20%, and the error effect rate is less than 10%.So the model has a good simulation effect, and its calculation approach is easy to be realized.More>
2010, 10(4): 115-120. doi: 10.19818/j.cnki.1671-1637.2010.04.019
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Simulation and identification system of vehicle safety operating speed on freeway
JIANG Gong-liang, LU Jia, YANG Li-gai
Abstract: The determined method of rational value for limit speed on freeway was studied, correlative simulation models and modules were established based on multi-body dynamics simulation software ADAMS.The models and modules included vehicle model, road model, vehicle-road coupling model, simulation test module of vehicle operating progress and identification module of vehicle safety status.The simulation and identification system of safety operating speed on freeway were empoldered, and the simulation analysis of vehicle operating statuses on curves and at downhill sections was done by using the system.Test result shows that the errors between the simulation values and standardization values of safety limit speed are in the range of 1.05% to 3.80%, so the simulation and identification system is feasible.More>
2010, 10(4): 121-126. doi: 10.19818/j.cnki.1671-1637.2010.04.020
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