2004 Vol. 4, No. 3

Display Method:
Prediction model of rain water depth on road surface
JI Tian-jian, HUANG Xiao-ming, LIU Qing-quan, TANG Guo-qi
Abstract: Rainfall and slope rough degree have great effect on rain water depth on road surface, and their relation is highly nonlinear, it can not be described by simple models. This paper used artificial neural network to establish the prediction model of water film thickness. Input layers of the model were rainfall intensity, gradient, slope length and contexture depth of road, output layer was rain water depth, there were 6 neural cells in hidden layer. The weights and thresholds of the model were attained through training neural network with testing data.Applied results show that the relative coefficient of predictive values and measure values is 0.98, error is 3.08. The result indicates that the predictive model is reasonable.More>
2004, 4(3): 1-3.
CFG pile strengthening technology of soft ground
JIANG Rong, LI Chang-ning
Abstract: This paper studied CFG pile strengthening effect of soft ground, which has low replacement ratio, with multiple field-testing techniques, such as static cone penetration test, plate loading test, low strain dynamic testing and settlement observation. The design method and construction technology of CFG pile were also represented concisely. It is pointed that the bearing capacity of composite foundation after treatment is 1.4~2.0 bold that of natural ground, CFG pile can not compact the soil between piles, in order to guarantee the consolidation time of settlement (50 mm) after projection, it needs no more than 0.5 year to reach the specified settlement for the zone used short piles, and no more than 1.0 year for the zone used long piles, and the rate of consolidation in the zone used short piles is higher than in the zone used long piles. The results indicate that this kind of CFG pile can guarantee bearing capacity and settlement after projection criterion of soft ground.More>
2004, 4(3): 4-7.
Asphalt pavement stress under overloading
CENG Fan-qi, HUANG Xiao-ming
Abstract: The actual distribution of axle load of main pavements was measured using the movable axle load meter to analyze the extent of overloading, some relative finite element programs were compiled to study the effect of vehicle load on asphalt pavement through changing vehicle load, and the effect of asymmetric load on pavement performances. The results show that the heavy load and overloading vehicles extensively exist throughout China, and tyre pressure is usually over 0.7 MPa, shear stress of surface, stress of base and subbase and pressure stress of subgrade are increasing up when the axle load increases, which indicates that overloading is a main factor of the early destruction of asphalt pavement.More>
2004, 4(3): 8-10.
Three-mass vehicle model of people-vehicle-road interaction
TAO Xiang-hua, HUANG Xiao-ming
Abstract: A simple three-mass vehicle model was founded on the basis of people-vehicle-road interaction. With this model, the amplitude and power spectral density(PSD) of vehicle dynamic load were calculated, the amplitude factor and PSD of acceleration were analyzed, the vibration characteristics of vehicle were evaluated, the relations of dynamic load with ride safety, acceleration and vibration comfort were discussed. The results show that this model can accurately reflect the dynamic response of people's comfort with pavement roughness.More>
2004, 4(3): 11-15.
Derailment analysis of freight train on old Luanhe bridge on Jingshan line in China
XIANG Jun, HE Dan, ZUO Yi-zhou, YANG Jun-xiang, ZHOU Zhi-hui, CENG Qing-yuan
Abstract: Derailment course of freight train running on the old Luanhe bridge of Jingshan up and down direction line was respectively calculated by the calculation model of special vibration of train-bridge time-variant system and the random energy analysis method of train derailment. Using energy increment criterion, the derailment case of freight train running on down direction line was calculated, and freight train running on up direction line was judged to be not derailed, which correspond to the fact. Meanwhile, the derailment reason of freight train running on down direction line was analyzed. It is pointed that the lack of bridge rigidity is the main reason causing train derailment, and bridge rigidity is the main controlled factor ensuring train's safety running on the bridge.More>
2004, 4(3): 16-19.
Dynamics performance simulation of double-deck container flat car
LIU Hong-you, YANG Ai-guo
Abstract: In order to learn about the function of NUCARS 2.3 in dynamics performance simulation for rolling stock, the dynamics of 25 t axle double-deck container flat car (DDCFC) in China was analyzed with NUCARS 2.3. Compared with line test results, including motion stability, negotiation performance and ride comfort of DDCFC. It is pointed that the ride comfort of simulation keeps well with the test results, but the value of negotiation performance indices of simulation are smaller than that of line test, the simulation results with NUCARS 2.3 can give the influence trend of car suspension parameters on car dynamics performance. The simulation results show that the method is feasible.More>
2004, 4(3): 20-24.
Automatic adjustment of train operation diagram in single-line block
XIAO Long-wen, XIE Ru-he
Abstract: This paper introduced a way of automatic adjustment for train operation diagram within the time-domain (t1, t2], proposed an index of the weighted sum of train delay-time for judging the quality of train-operation-diagram adjustment. In order to optimize the index, a mathematical model and simplified model were presented. Based on the simplified model, a network chart was constituted, by the means of branch delimitation theory, an algorithm for the adjustment of train operation diagram was designed. Simulation results show that the algorithm and model are feasible, can give a real 3~4 h plan of train operation in shorter time.More>
2004, 4(3): 25-29.
Traction calculation of urban mass transit
SHI Hong-guo, PENG Qi-yuan, GUO Han-ying
Abstract: Based on studying metro's traction characteristic figures and brake characteristic figures, this paper put forward three representative policies of traction calculation, the quickest policy, the most economical policy and the perfect policy. According to the quickest policy, metro's operation was divided into start-up and traction process, stop and pulling process, and keep running at limit velocity operation process. Aiming at these processes, their traction calculation software models and arithmetics were presented. Tested calculation results indicate that the traction system can calculate the shortest travel time with the models and arithmetics, and make train pulling process more veracious.More>
2004, 4(3): 30-33.
Structural topology optimization design based on strain energy
DU Hai-zhen, RONG Jian-hua, FU Jian-lin, YANG Zhen-xing
Abstract: The man-made material is added around optimal structural cavities and boundaries. Based on evolutionary structural optimization (ESO) method and element strain energy analysis, a structural topology optimization method was developed with strain energy analysis. The basic theory of topology optimization was given, and the formulae of ESO method with the function of removing and adding elements were derived. Simulation designs of bridge pier and bridge structure with isotropic material were completed by the proposed method. Simulation results show that the difference between the maximum and minimum strain energy remarkably becomes little, and the topology structures are similar to the ones in engineering, which indicates that the basic principle of the proposed method is feasible for structural topology optimization.More>
2004, 4(3): 34-37.
Calculation methods for cable curve of self-anchored suspension bridge
DI Jin, WU Juan
Abstract: Took Sanchaji suspension bridge in Changsha as a case study, based on different hypothesis, two methods were deduced, the parabola method of cable gravity distributing uniformly along the span, and the catenaries method of gravity distributing equally along the curve. It is pointed that the parabola method is straightforward, but the results are relatively coarse, and the catenaries method is relatively complicated, but the results are precise, which takes into account all-around factors. For the two methods above, the error of vertical coordinate of cable is 0.739%, and the error of zero-stress length for cable is 0.31%. The results show that the two methods are feasible to calculate the cable curve of self-anchored suspension bridge.More>
2004, 4(3): 38-43.
Overturning stability analysis of curved box girder bridge
DING Han-shan, LIU Hua, HU Feng-ling, WANG Xin-ding, ZHOU You, ZHANG Yi
Abstract: Overturning stability analysis of curved box girder bridge in Huaiyang highway interchange over the Huaihe to sea waterway was introduced. The major factors, which would cause bridge overturning, were analyzed by the finite element method, and preventive measures were advanced in bridge design. Analysis results show that the overturning stability of curved box girder bridge is mainly behaved in the torsional distortion and the bearing reaction, the supporting fashion must be designed to avoid negative vertical reaction of bearings.More>
2004, 4(3): 44-48.
Optimal signal-planning method of intersections based on bus priority
ZHANG Wei-hua, LU Hua-pu, SHI Qin, LIU Qiang
Abstract: By the traditional signal-planning method, cycle is determined according to minimum average vehicle delay, green time is determined according to the vehicle flow ratio of phases. The traditional signal-planning method is unfair to these phases with a big proportion of bus, because a bus can load more passengers than a non-bus does. This paper set up a signal-planning method, in which the average people delay is regarded as an optimal aim of cycle, and green time is determined according to passenger quantity and the saturation of phases. When according to this method to plan signal time, though average vehicle delay is bigger than that of traditional method, but average bus delay and people delay are reduced near 30%. Applied results show that this signal-planning method provides priority for bus, and reduces bus delay on the premise of ensuring smooth traffic.More>
2004, 4(3): 49-53.
New method of public transit network assignment based on GIS
GE Liang, WANG Wei, YANG Ming, DENG Wei
Abstract: Based on analyzing the diminutive relationship of bus running time and link flow, and the limited capacity for bus, the concept of congestion function was proposed to describe the relation of trip resistance and flow, transit network resistance was investigated combined with transit time chain. Then the multi-route probit-based loading model was established, and the algorithm was put forward to achieve a more precise result, the network assignment method was combined with GIS technology. Applied results show that the computation values almost accord with the measure values.More>
2004, 4(3): 54-58.
Recursive estimation of O-D matrix through a region with lagged traffics
LI Mao-sheng, SHI Feng
Abstract: This paper gave a multi-linear recursive model with probability-constraints, and designed an algorithm following the viewpoint of the model for estimating the O-D matrix through a region with lagged traffics. The stability of the model was analyzed in the conditions of experimentation errors. The estimation error of the model is about 8%, when the error of traffic flow is less 3%, which shows that the model is feasible.More>
2004, 4(3): 59-63.
Macro layout method of traffic count stations
CHEN Hong, CUI Shi-hua
Abstract: Based on the principles of objectivity, reliability and practicability, this paper set up traffic count stations using fuzzy clustering and correlation analysis. The whole idea and flow chart of stations layout were established considering the layout principles and choice rules of traffic volume changing critical point. According to the index of road important extent, the layout type of stations was decided. Then a quantitative and systematic method of macro layout to traffic stations was put forward. Applied results show that the method can select representative roads and determine count stations location and number, the layout result meets with the demands of the actual road state.More>
2004, 4(3): 64-68.
Network system and operation models of freight transportation station
XU Shuang-ying
Abstract: Focusing on the planning and actual operation situation of Chinese highway freight transportation stations (HFTS), and the linkage characteristics of economics and logistics applying the view and method of logistics, systemization, this paper proposed the highway freight station system based on inter-station linkage, and discussed its operation models. It is pointed that the logistics organization and operation models can well integrate logistics resources, link individual parts of logistics process, and can provide the more convenient, punctual, flexible right integration logistics services for sociality to gain well profits.More>
2004, 4(3): 69-72.
Transportation trunk system planning of coordinative multimode
WANG Yuan-qing, HE Zhu-qing
Abstract: Based on the analysis of existing planning and implementation method of multimode on transportation trunk in China, the deficiency of planning concept, object, function and connection was reviewed. According to the characteristics of economy and function of transportation trunk, the improved planning and implementation method for multimode transportation trunk were studied using the systems analysis. The improved method involving the location theory, function analysis, mode superiority analysis, had the ability of covering the existing planning and implementation method and remedying its deficiency. The analysis indicates that the improved method is feasible for planners to implement the coordinative multimode planning, which contains alignment correction, function-oriented planning method, junction planning method and evaluation method in the stage of layout planning.More>
2004, 4(3): 73-78.
Ant colony algorithm of distribution network planning
ZHAO Jian-you, YAN Wang, HU Da-wei
Abstract: Based on analysing the complicated, nonlinear combinatorial optimization problem of distribution network planning, this paper put forward a mathematic model of network planning and an ant colony algorithm taking the minimum sum of operation cost, reliability cost and investment cost as object. The computing result of the algorithm accords with the real situation of network planning, which shows the algorithm is feasible.More>
2004, 4(3): 79-81.
Determining method of traffic impact range of project
PEI Yu-long, WANG Xiao-ning
Abstract: This paper studied the methods of determining threshold values of traffic impact range, set up a new model that the decreasing of service level of signal intersection surrounding projects by one grade was regarded as the threshold value to determine traffic impact range. Applied results show that the traffic impact range can meet the demand of traffic impact analysis and save resource farthest, which indicates that the method is simple and effective.More>
2004, 4(3): 82-84.
Development of passenger transport system
ZHANG Zhou-tang
Abstract: With comparative method, this paper scientifically analyzed the process and common regular of passenger transport system evolution, studied the differences of various countries. It is pointed that the technical and economic characteristics of transport modes and passenger transport demand characteristics and their changes are basic factors influencing passenger transport system evolution, national condition is an essential factor forming the discriminations. Analysis results indicate that when choosing reasonable passenger transport system mode, one country must not only grasp passenger transport system common regular, but also must put more attention to its national condition.More>
2004, 4(3): 85-89.
Application of CAN bus system in hybrid electric vehicle
ZHU Zheng-li, YIN Cheng-liang, ZHANG Jian-wu
Abstract: The paper described the necessity of applying CAN (controller area network) to hybrid electric vehicle, analyzed the high reliability and flexibility of CAN, and the characteristics and protocol of the bus. The research on the realization of CAN bus system was carried out by using three buses in the design. Experiment results prove that the system is feasible, because it can fulfill the requirements of hybrid electric vehicles. The loading of CAN bus is lower, the error ratio is about 10-8~10-6 when the transmission rate is middle or high, and the power consumption is lower than the design requirement.More>
2004, 4(3): 90-94.
Performances of spark ignition engine fueled with DME-LPG blends
WANG Heng, QI Dong-hui, BIAN Yao-zhang
Abstract: By contrasting the testing results of engine fueled with dimethyl ether (DME) blends and gasoline, this paper evaluated the practical characteristics of different component and the ratio of DME blends on spark ignition engine. The investigation and analysis of power performance, fuel economy and idle emissions were carried out on spark ignition engine fueled with two different ratio blends, which were made up of DME, liquefied petroleum gas (LPG) and methanol. The results indicate that the antiknock property of DME-LPG blends is better than that of gasoline, through adjusting the fuel supplying and ignition system of engine, the power of DME-LPG blends is greater than that of gasoline at low and middle engine speed, lower than that of gasoline at high engine speed, the specific fuel consumption of DME-LPG blends is lower than that of gasoline under all range of load, the HC, CO and NOx emissions of DME-LPG blends are obviously reduced compared with gasoline under idling condition. The performance of DME-LPG blends engine is generally the same as that of gasoline engine.More>
2004, 4(3): 95-98.
Reconstruction of 3-D ship hull surface based on NURBS
SHI Guo-you, JIA Chuan-ying
Abstract: In allusion to the ship hull surface modelling in simulation system of loading and unloading awkward length cargo, this paper provided the main steps of reconstructing ship hull surface by NURBS (non-uniform rational B-spline). According to the points in offset table, the knot vector was calculated with an accumulative chord length parameterization, the global interpolative crosscut lines and waterlines were available with NURBS technology, and the regulative interpolative grid of ship surface was made, thus the ship surface presented with NURBS was reconstructed. The simulation results show that the 3-D ship hull surface reconstructed by NURBS is highly real, this method is feasible.More>
2004, 4(3): 99-103.
Safety evaluation of beginning voyage ship in heavy weather
WANG Feng-wu, WU Zhao-lin, ZHENG Zhong-yi
Abstract: From the point of system engineering, the affecting factors and their important degrees of beginning voyage in heavy weather were studied, the system of assessment indices and assessment model were built by AHP (analytical hierarchy progress). The safety evaluation of beginning voyage was developed by using comprehensive assessment theory. Applied results indicate that the evaluation method can provide scientific quality indices of safety.More>
2004, 4(3): 104-107.
Main parameters of waterway lock capacity
ZHANG Wei, LIAO Peng, WU Ling-li, HUANG Hai-ou, TAO Gui-lan, DING Jian
Abstract: This paper analysed the lock capacity and its main influencing factors of the grand canal in the northern part of Jiangsu province. It is pointed that the barge and the boat of Shiqiao lock are mainly distributed in 100~300 t and 50~300 t, their average tonnages are 228 t and 168 t, and the relative utilization rates of lock chamber for the barge and the boat are focused between 0.4~0.7 and 0.6~0.7 in 2001. Analysis results show that ship type, ship tonnage and the relative utilization rate of lock chamber are the main influencing factors of lock capacity.More>
2004, 4(3): 108-110.
Effect factors of tire critical speed
YU Zhi-guo, LI Shu-lin, LIU Zhi-hong, LI Hong-peng
Abstract: Based on analysing the effect factors of tire critical speed for raising/avoiding critical speed, a mechanical model of tire was established based on some reasonable hypotheses and vibration theory, the relation between distortion resume time and effective mass was obtained. It is found that the critical speed is connected with load, inflation, radial distortion and surface abrasion, increasing inflation while maintaining load constant or inducing load while keeping inflation unchangeable can raise tire critical speed. The analysis results accord with the real situation of tire, which indicates that the model is feasible.More>
2004, 4(3): 111-113.
Evidence theory application in performance review of aviation equipment
ZHENG Dong-liang, DU Chun
Abstract: In order to quantify many uncertain factors in reviewing of aviation equipment reliability-maintainability-supportability (RMS) and make fully use of implicit knowledge of experts, RMS review model based on evidence theory was set up. Through evidence combination, the uncertainty in the RMS review process of aviation equipment is get rid of or controlled, the scientificness of RMS review decision is improved.More>
2004, 4(3): 114-116.
Mathematical programming model of aircraft assignment
SUN Hong, DU Wen
Abstract: Based on analyzing the characters of single hub and spokes network, which is used in China airliners, and the principles and working flow of aircraft tail number assignment (TNA) problem, studying the mathematical models of aircraft TNA problem, this paper introduced a new concept called "flight pairing", put forward a new TNA model, which classified a specific TNA problem into one of three typical TNA modes, TNA based on fleet dispatching commands, TNA based on fleet balance application, TNA based on minimum fleet requirement. Applied results show that the error of TNA is only 4.8 min, the time of attaining TNA is only 23 s, which indicates the model is feasible.More>
2004, 4(3): 117-120.
Application of genetic algorithm to aircraft sequencing in terminal area
XU Xiao-hao, YAO Yuan
Abstract: This paper applied the genetic algorithm (GA) to study runway assignment, sequencing and scheduling of arrival flight in the terminal area, set up a mathematic model of comprising multiple runways and multiple aircrafts. Applied results show that the adaptive degree increasing percent of GA is 80%, the delay time reducing percent of GA is 40%, contrasted with first come first serve (FCFS), which demonstrates that GA is better than FCFS to solve above questions.More>
2004, 4(3): 121-126.