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20 October 2008, Volume 27 Issue 5 Previous Issue    Next Issue

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Influence of Under-Pylon Foundation Forms on Seismic Performance of Super-Span Cable-Stayed Bridges PENG Kai, LI Jian-zhong, PENG Tian-bo 2008, 27(5): 665-671,825.  Abstract ( )   PDF (634KB) ( )   Based on a super-span cable-stayed bridge over Yangtze River,which is planned with two optional pylon foundation forms: caisson and pile,modal participating mass ratio distribution and modal period distribution of free structural vibration modes involving distinct horizontal participation of the under-pylon huge-mass pile caps are studied by contrast.Artificial ground motions are applied in linear time-history analysis to calculate the controlling seismic responses of the bridge structure with caisson-form pylon foundations and alternative pile-form ones,then the results of the two cases are compared at the same structural locations;and in the horizontal directions the contribution of the under-pylon huge-mass pile caps to the cap bottom seismic reactions are analyzed in time domain as well as frequency domain.The research indicates that participation of the under-pylon huge-mass pile caps in high-order structural vibration modes essentially influences the dynamic properties and seismic responses of the super-span cable-stayed bridge,and sharply magnifies the horizontal seismic foundation reactions at the pylon cap bottoms compared with the case of caisson-form pylons foundations,which increases the seismic vulnerability of the super-span cable-stayed bridge. Related Articles | Metrics

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Calculating Method of Eccentric Loaded Coefficients of Simple Supported Girder Bridges with Plane Finite Bar Elements XU Yi, HUANG Xu 2008, 27(5): 672-674,694.  Abstract ( )   PDF (270KB) ( )   Though simple supported girder bridge is used widely,the calculation of its stress,strain and displacement is complex.Based on the analysis of transverse load-distributing influence lines and eccentric loaded coefficients,a relatively simple calculating method is proposed in virtue of plane finite bar element software,and then an example is taken to calculate.The results of calculation confirm that this method is right and feasible. Related Articles | Metrics

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One Calculation Method of Creep Deformation in Bridge Linear Controlling CHEN Wu-si, ZHANG Bao-li, GUO Rui-dong, ZENG De-rong 2008, 27(5): 675-678.  Abstract ( )   PDF (272KB) ( )   Monitoring the long-span continuous rigid bridge construction,linear controlling mainly concentrates on the pre-camber settings.And pre-arch is closely linked with the cach of bridge structure deformation.The concrete creep deformation is difficult to calculate accurately,therefore,a theoretical formula is established theoretically to calculate this kind of creep deformation.Its calculating results are basically consistent with those got by other methods,but its simple calculation and high precision are advantageous. Related Articles | Metrics

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Analysis on Stress Influence of Thickness of Deck Pavement on Structure Force under Sunlight Nonlinear Temperature Difference WANG Lei, WU Hai-jun, ZHOU Zhi-xiang 2008, 27(5): 679-684.  Abstract ( )   PDF (443KB) ( )   The main diseases of deck pavement and their importance are introduced.However,the influence of sunlight nonlinear temperature difference has no rule to follow in the current design theory of deck pavement.By choosing different deck pavement layer thickness,the contrast tests of structural stress changes of key section in various kinds of decks are analyzed respectively,through simulating the process of heating and cooling with finite element.The rules that the different deck pavement layer thickness exerts an influence on the stress have been worked out.Finally,the reasonable suggestion about the selection of the typical bridge's deck pavement layer thickness is put forward. Related Articles | Metrics

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Research on Special Program Development for Calculating Internal Force of Arch Bridge ZHOU Xiao, ZHOU Shui-xing 2008, 27(5): 685-688,704.  Abstract ( )   PDF (488KB) ( )   Based on the classic calculation theory of arch bridge,a special program which could be used to calculate internal forces of deck type and half-through arch bridge has been developed in virtue of Visual Basic Language.Two specifications about 1985 and 2004 are included in this special program.It could carry out not only the optimization of arch-axis coefficient,but also the calculation of dead load,live load and additional force.In addition,combination of internal forces and checking of bearing capacity could also be automatically realized.This special program features with high calculation precision,convenient operation and strong feasibility. Related Articles | Metrics

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Study on Influence of Shape and Reinforced Measures on Seismic Response in Large-Scale Shaking Table Model Tests WU Wei, YAO Ling-kan, CHEN Qiang 2008, 27(5): 689-694.  Abstract ( )   PDF (627KB) ( )   Revealing the influence of soil properties and slope shape on ground motion parameters of rock is the key to earthquake control design of slope engineering.The contrast test between slope model and layered soil model experiments through shaking table,as well as the contrast test between reinforced layered soil model and layered soil model are carried out.It is found that compared with layered soil,the amplitude magnification coefficient of seismic acceleration will increase by almost 30% in slope with free face;compared with layered soil,the amplitude magnification coefficient of seismic acceleration in reinforced layered soil can be reduced by 20%.In addition,the dynamic properties of the models under seismic force are discussed.It is found that the self-vibrating frequency of one model will decrease after repetitive vibration,and at the same time,the seismic acceleration of the soil shows a larger amplification. Related Articles | Metrics

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FEA of the Effect on Anti-slippery Performance of the Frictional High-Strength Bolt Caused by Gasket WANG Ji-wu, LING Ling, WANG Zi-jian, GUO Zheng, SHI Lei 2008, 27(5): 695-697.  Abstract ( )   PDF (315KB) ( )   The simplified model connected by the high-strength bolts was established by making use of the ANSYS 9.0 software.The anti-slippery performances of the M20 frictional high-strength bolts,which had the various-size gaskets,were carried out by the nonlinear analysis.Moreover,the ANSYS digital results with the various-size gaskets were dealt with the comparative research.These indicate that the various-size gaskets have some influence on the anti-slippery performances of the frictional high-strength bolts.Therefore,some significant references to the actual engineering are offered. Related Articles | Metrics

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Research on Effects of Shi-banpo Multiple Track Bridge Special-Purpose Cement on Properties of Concrete WANG Rui-yan, LI Bin, ZHANG Chi 2008, 27(5): 698-700.  Abstract ( )   PDF (241KB) ( )   Special-purpose cement is produced to fit for the structural and constructive characteristics of Shi-banpo Yangtze multiple track bridge.Through controlling mineral consistence and hydration heat of the special purpose cement,it can reduce the temperature rising,improve the volume stability and durability of concrete directly and effectively.By using the special-purpose cement,HPC possesses good synthetic technical performance. Related Articles | Metrics

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Study and Application on Ceramist Concrete of Reinforcing Old Bridges for Bridge Deck Pavement CAO Zhong-jie, DONG Ying-ying, JI Yi-lai, LIU Jun, LING Tian-qing 2008, 27(5): 701-704.  Abstract ( )   PDF (415KB) ( )   It is inevitable to build a large number of bridges along with booming of our country's highway and transportation,and give the maintenance,reinforcement and technical improvement to some old bridges.The feature of ceramist and ceramist concrete,and its feasibility to conduct structure for bridge deck pavement are analyzed.Mixture ratio was made by indoor tests and the performance of mechanical property,freeze resistance,abrasion resistance was studied;construction technology and technical requirements were discussed according to ceramist concrete pavement. Related Articles | Metrics

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Numerical Simulation of Fracture Propagation of Concrete on Meso-level WU Feng, ZHUO Jia-shou 2008, 27(5): 705-708,834.  Abstract ( )   PDF (468KB) ( )   Concrete is taken as three phases' composites consisting of aggregate,matrix and bond between matrix and aggregate on meso-level.The model and arithmetic of Interface Element Method (IEM) is introduced to illustrate and verify the correctness of this meso-model.And the devastation process and fracture enlarging process of concrete sample under uni-axial loading are simulated numerically. Related Articles | Metrics

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Analysis on the Structural Characteristics of ITZ of Recycled Concrete WEI Hong, LING Tian-qing, QING Ming-jian, WU Chun-bo 2008, 27(5): 709-711,821.  Abstract ( )   PDF (436KB) ( )   Based on the observation of SEM and EDXA technologies,the investigation on the micro-structural properties and the elements distributional characteristics of Interfacial Transition Zone (ITZ)of recycled concrete is conducted.The observation results show that the recycled concrete consists of various interfacial structures and the ITZ depth is greatly different from each other.Further studies indicate that the distribution of elements of the ITZ is seriously different in other areas;Ca,Si,and et al elements have partially gathered in the ITZ but continually distribute in the other areas. Related Articles | Metrics

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Faulting Mechanism of Cement Concrete Slab YANG Qing-guo, YI Zhi-jian, LIU Zhan-fang 2008, 27(5): 712-716.  Abstract ( )   PDF (548KB) ( )   The traditional mechanism of cement concrete slab faulting exists some inaccuracies,so some phenomena can not be interpreted.The interactions between cement concrete surface course and base course will theoretically lead to three basic damage types in base course,in other words,the base course will lose its integrity.Based on this proposition,the reason of cement concrete slab faulting is renewed.The new mechanism of cement concrete slab faulting has been proved by the investigation of the actual road.The new cement concrete slab faulting mechanism has some theoretical and actual significance for the prevention of cement concrete slab damage. Related Articles | Metrics

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Study on Influence Factors in Design of Asphalt Overlay on Old Cement Concrete Pavement WU Guo-xiong, CAO Yang, FU Xiu-zhu 2008, 27(5): 717-721.  Abstract ( )   PDF (387KB) ( )   At present,all of the designs of asphalt overlay on old cement concrete pavement at home and abroad are not perfect,and there is no accepted reasonable and feasible design method.Based on the previous studies,through a three-dimensional finite element analysis program to compute the mechanical response of asphalt overlay with geosynthetics interlayer under the action of load,the influence of parameters like asphalt overlay thickness,asphalt overlay modulus,old cement concrete pavement modulus,geosynthetics modulus,foundation modulus on the stress and deflection in the bottom of asphalt overlay are analyzed.Thus the important factors which should be paid attention to in overlay design method are pointed out,and the design method of asphalt concrete overlay on the old cement concrete pavement considering the reflective cracking is further discussed and explored. Related Articles | Metrics

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Design and Construction of Continuously Reinforced Concrete Pavements ZHANG Hong-liang, WANG Bing-gang 2008, 27(5): 722-728.  Abstract ( )   PDF (781KB) ( )   Continuously reinforced concrete pavement (CRCP) is smooth and almost needs no maintenance,which has long service life as well as a promisingly potential application.CRCP is introduced in detail from design factors,structural response analysis,design,construction,and et al.Different from 1993 Design Guide of AASHTO,2002 Design Guide selects punchout development and smoothness as design criteria.The research on CRCP at home has been still far behind that at abroad.Based on the analysis of the faults in previous research on CRCP,it is pointed out that the research on CRCP in the future will be focused on the following aspects:punchouts prediction based on the distribution of transverse crack width and spacing,crack width prediction under repeated vehicle-load and natural conditions,the calculation of the critical transverse stress at the top of the slab when the loss of base support and the Load Transfer Efficiency (LTE) of cracks or joints are considered,the asphalt pavements with the base course made up of continuously reinforced concrete,and the material composition design of different structural course according to their performance requirement. Related Articles | Metrics

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Application of High-Performance PDA to Road Engineering TANG Dai-hua, FENG Xiao, SONG Xiao-ming 2008, 27(5): 729-732.  Abstract ( )   PDF (434KB) ( )   Through the research on the current situation of PDA application to road engineering at home and abroad,a kind of survey and design integration system inside or outside road job is proposed based on high-performance PDA.The function of main modules,the development and runtime environment of the system have been illustrated.The system is powerful,efficient,real-time,visual,and easy to operate. Related Articles | Metrics

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Application of Digital Image Technology to Exposed-Aggregate Concrete Pavement LIU Liu, LIANG Nai-xing, WANG Le 2008, 27(5): 733-735.  Abstract ( )   PDF (306KB) ( )   Digital image technology is applied to deal with the exposed-cement concrete pavement photos taken by ordinary digital cameras.According to the analysis of the image gray scale change,the texture depth of road surface is got;and through the comparison with the conventional method,it indicates that this method of the road texture surface measuring the depth features in its reliability and simple operation.It can be used in analyzing the characteristics of the exposed-aggregate concrete pavement. Related Articles | Metrics

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Determination of Equivalent Axle Load Factors for Asphalt Expressways Using Load Spectra ZHAO Yan-qing, WANG Jia-jie, HE Chang-xuan, YE Qin 2008, 27(5): 736-739,842.  Abstract ( )   PDF (412KB) ( )   Traffic loading is one of the most important parameters in pavement analysis and design.However,currently the Equivalent Axle Load Factors (EALFs) are chosen arbitrarily in calculating the number of equivalent single axle loads (ESALs),and the results could not reflect true traffic conditions.Thus Weight-in-Motion (WIM) data were collected from 2004 to 2006 at 20 expressways in Jiangsu province,and load spectra parameters were determined through the analysis.The difference between AASHTO 1993 and China ESAL calculation methods were analyzed.EALFs of various types of vehicles were determined using both AASHTO1993 and China methods,and results could be used in pavement analysis and design.ESALs for mixed traffic are calculated,and it is pointed out that the difference of EALF calculation methods should be taken into account in comparing the domestic and foreign traffic volumes. Related Articles | Metrics

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Analysis on Properties of Oxygen-Asphalt Mixtures by Grey Relation Theory RAO Jian-cheng, LIU Yin, CAO Xue-juan 2008, 27(5): 740-742,757.  Abstract ( )   PDF (309KB) ( )   The oxygen-asphalt mixtures properties are analyzed by grey relation theory under different test conditions.It takes Marshall stability as the fundamental index of evaluation.The elements that the test mainly involves are oxygen contents,bitumen aggregate ratio,percentage of void,the mixing heat preservation temperature,the mixing heat and preservation time.Adopting the analytical theory of the grey relation,the impact degree of different elements on Marshall stability of the oxygen-asphalt mixtures is worked out,that is,oxygen contents> bitumen aggregate ratio> the mixing heat preservation temperature> the mixing heat and preservation time> percentage of void.Thus it can provide guide to the design and construction of the oxygen-asphalt mixtures. Related Articles | Metrics

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Analysis on High Temperature Stability of Fibers-Reinforced Asphalt Mixtures with Grey Correlation Entropy Method XIONG Rui, YANG Xi-wu, YANG Fa, TU Shuai, YANG Xiao-li 2008, 27(5): 743-747,789.  Abstract ( )   PDF (398KB) ( )   With traffic channelizing and axle-load's increasing,the rut becomes the main form of high temperature deformation.It is the result of interaction of many factors.Based on the wheel rutting test,the influencing factors on high temperature stability of both AC-13I and AK-13I asphalt mixtures are discussed,which different percent of Dolanit ® AS fibers is added into.Moreover,the grey correlation entropy method is utilized to analyze different factors such as fiber content,asphalt penetration,asphalt content,the percentage of 4.75 mm sized aggregate passing through the mesh,volume of air voids in asphalt mixtures and voids filled with asphalt.The results indicate that fiber content and volume of air voids have a great effect on Dolanit ® AS fibers-reinforced asphalt mixtures. Related Articles | Metrics

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Creep Experiments Evaluating the Flowing Deformation of the Asphalt-Treated Permeable Base in High Temperature Condition YANG Da-tian, XIA Wen-jun, YANG Xi-wu 2008, 27(5): 748-752.  Abstract ( )   PDF (344KB) ( )   The optimum asphalt-aggregate ratio of six kinds of asphalt-treated permeable bases is found out according to large scale Marshall tests.The samples of using the creep test are stroked by the large scale Marshall Sample.Creep modulus and value gained by the static creep experiment evaluate the flowing deformation of six types of asphalt-treated permeable in high temperature condition.At the same way,value gained by the dynamic creep test can also do this.It tries to prove that the best anti-deforming ability of the asphalt-treated permeable base mixtures is between upper limit and the middle value in the minerals aggregate grades,in the high temperature condition.Therefore,minerals aggregate grade curve should be between upper limit and the middle value;ATB-25 should be close to the medium value,and ATB-30 should be close to the upper limit. Related Articles | Metrics

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Study on Road Performance of the Cement Strontium Dregs Stabilized Gravel Mixture WEI Guang-lin, TANG Bo-ming, ZHU Hong-zhou, HU Ke 2008, 27(5): 753-757.  Abstract ( )   PDF (576KB) ( )   In view of the application of strontium dregs in rural highway basic unit,strontium slag cement stabilized gravel mixture is adopted.By two types of basic mixtures,that is suspension dense and skeleton dense,which are always used in projects,anti-lateral limits compressive strength of the mixture,splitting strength,compression modulus of elasticity,water stability,shrinkage properties,such as temperature reduction of the major cement stabilized granular mixture of the grass-roots level with the road performance are studied.The road performance of the strontium slag cement stabilized gravel mixture is summed and it offers technical reference to application of strontium slag cement stabilized gravel mixture. Related Articles | Metrics

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Analysis of Effect on Spiral Transition Curve on Traffic Safety WANG Fu-jian, WU Guo-xiong, Said M. Easa 2008, 27(5): 758-762,838.  Abstract ( )   PDF (427KB) ( )   The literature review shows that the unreasonable length of spiral transition curve may affect driving behavior and traffic safety.So 39 plane curves and their four-year traffic accidents (2001-2004) of Shang-san Freeway,5 plane curves and their six-year traffic accidents (1999-2004) of Hu-hang Freeway and 6 plane curves and their four-year traffic accidents (2001-2004) of Hang-ning Freeway in Zhejiang Province of China are investigated and analyzed.The result indicates that the accidents on spiral transition curves are not abnormal,therefore it can be considered that the lengths of spiral transition curves in the freeways are reasonable and feasible,and don't affect traffic safety markedly.In the investigated curve radius range [400m,3819.516m],the ratio (A/R) of spiral transition curve's parameter A and circular radius R,is in good minus power relation with R,and its changeable range is in (1/3~1/2) basically,which is in agreement with the conventional knowledge and the recent investigations in literatures.The results can be used as the more specific quantificational references in design. Related Articles | Metrics

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Research on H-Fuzzy Evaluation Method for Traffic Congestion of City Road-Network REN Qi-liang, XIAO Yu-min 2008, 27(5): 763-766.  Abstract ( )   PDF (271KB) ( )   According to the characteristics of spatial-distribution of traffic congestion,city road-network traffic congestion is divided into road section congestion and cross congestion.Consulting the division standard of city road and cross service level,city road-network traffic congestion is classified into five grades:congestion,crowd,general crowd,general unimpeded and unimpeded.The indexes to evaluate city road network traffic congestion are selected.Through the Analytic Hierarchy Process,two hierarchy evaluation index systems and corresponding H-Fuzzy comprehensive evaluation model are established.Finally,the H-Fuzzy evaluation method is used to evaluate the traffic states of one typical city road network.The research results provide an effective quantitative analysis to evaluate city traffic congestion. Related Articles | Metrics

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Analysis on Traffic Accidents Law and Its Countermeasures of Rurbania Roads LIU Tang-zhi, TANG Bo-ming, LING Jian-ming, LIU Li 2008, 27(5): 767-771,798.  Abstract ( )   PDF (608KB) ( )   Combining with the present situation of traffic safety of rurbania roads in China,the general characteristics of the rurbania roads and the law traffic accidents are analyzed on the basis of the investigation of two typical rurbania roads.Some preventive strategies and countermeasures to improve the rurbania roads have also been proposed in the respects of planning,design,construction and operation.In addition,some new design concepts are put forward,such as forgiving designing,side buffer area,and combinatorial planning of urban roads and highways.And some countermeasures are proposed,such as adding special lane for motorcycles,using bituminous road pavement,constructing visual oscillating speed-control area,taking the arrangement distinguish method of traffic accident black spots,and strengthening traffic education. Related Articles | Metrics

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Analysis on Electric Bicycles' Current Traffic Situation and Countermeasures SHI Chen-peng 2008, 27(5): 772-775.  Abstract ( )   PDF (316KB) ( )   Aiming at some serious problems in the development of electric bicycle at the present time,the driving stability and crash character are analyzed from the point of the traffic safety character.Countermeasures,such as management in strict accordance with law,performing license plate and driving license management and driving permission system are proposed to promote the healthy development of electric bicycle traffic. Related Articles | Metrics

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Study on Network Management's Feasibility and Network Scheme of the Main Passenger Station——A Case Study of Chongqing Urban Area ZHANG Hui-ling, AO Gu-chang 2008, 27(5): 776-780.  Abstract ( )   PDF (461KB) ( )   Through the introduction of the current situation of planning and operation management of passenger station in Chongqing urban area,the problems of the operation management and the necessity of network management are pointed out.Then,considering the passenger's demanding and the management department's requiring,the scheme of the network operation is worked out and each subsystem's function is described.With the project's implement,the information of each station and route can be used effectively;the passenger can know the relative message and the management department can get the real-time data.Thus,the service level of the passenger transportation can be greatly improved. Related Articles | Metrics

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Research on Transit Quality of Service Measure System and Method Based on Passenger's Perspective HUANG Ting, JIAO Hai-xian, LI Xiu-li, ZENG Xiao-lin 2008, 27(5): 781-784,830.  Abstract ( )   PDF (411KB) ( )   From passenger's perspective,based on the factors that affect passenger transit trip and transit trip decision-making process as well as the studies on transit availability,travel time and cost,comfort and convenience,safety and security aspects,measure index for transit stop,transit line and transit system are proposed and the humanized quality of service measure system is established.Finally,the system is evaluated comprehensively in virtue of AHP method.The transit quality of service measure method based on passenger's perspective is very meaningful for improving transit quality of service and choosing transit network resource optimization. Related Articles | Metrics

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Numerical Simulation and Stability Evaluation of Excavation Process of High-Cutting Slope in Road Project——A Case Study of K95 Section in Wushan-Wuxi Road CAO Wei-wen, TANG Hong-mei, YE Si-qiao 2008, 27(5): 785-789.  Abstract ( )   PDF (419KB) ( )   According to the actual condition of high-cutting slope of Wushan-Wuxi Road K95 section,general-purpose finite element program ANSYS is used to simulate excavation process.The rock mass' isoclines for stress,displacement etc of excavation before and after are got,and then a comparative test is made.Further,according to the node coordinate of plastic deformation area,latent glide plane equation is got by least squares theory.Hereby,stability evaluation for the high-cutting slope is carried out and effective disposal countermeasures are put forward. Related Articles | Metrics

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Study on Blasting Mechanism of High Pressure Core in Debris Flow CHEN Hong-kai, DU Rong-huan, TANG Hong-mei, WANG Quan-cai 2008, 27(5): 790-793.  Abstract ( )   PDF (401KB) ( )   At present,no theory at home and abroad can be used to interpret some phenomena reasonably and simultaneously.The phenomena include surging motion of debris flow,anti-grade deposits and fluctuation motion for coarse particle on debris flow.It is assumed that there is a high-pressure core by different velocities of solid and liquid in debris flow snout.When interior pressure in the core increases and reaches a critical value,the core blasts suddenly.This process is named as blasting mechanism of high-pressure core in debris flow.These phenomena mentioned above can be explained reasonably by particle buoyancy,collision forces and additional water pressure during formation and blasting of high-pressure core.Further,formation and evolution process of high-pressure core must be checked and observed by testing;meanwhile,the mechanics of blasting mechanism of high-pressure core in debris flow should be established. Related Articles | Metrics

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Fuzzy Comprehensive Evaluation Method and Its Application in Judging the Risk Degree of Debris Flows WANG Zi-jian, XIAO Sheng-xie, DAI Ting-li, WU Li-ming, WANG Wei 2008, 27(5): 794-798.  Abstract ( )   PDF (343KB) ( )   Aiming at the analysis of the debris flow disaster characteristics,the evaluated factors and the nonlinear subordinate functions are selected to determine the membership degree of every factor.The weights of the impacted factors are determined by the hierarchy process.The dangerous size of the mudslides is assessed by the secondary fuzzy analytic method.And the example assessed by the dangerous size of the five debris flow ditches in Yunnan show that the fuzzy analytic method can reflect the dangerous conditions of the debris flow,and it provides the decision-making basis for the debris flow prevention and the project reinforcement. Related Articles | Metrics

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Research on Selecting an Appropriate Project Delivery System LI Xing-su, SUN Hong-bo, HUO Xiao-chun 2008, 27(5): 799-802.  Abstract ( )   PDF (333KB) ( )   Influenced by the specific conditions of the project and the characteristics of owners and constructors,various kinds of project delivery systems have their own advantages and disadvantages in the practical construction.Based on the former research at home and abroad,using Analytical Hierarchy Process (AHP) to select the appropriate project delivery system is put forward.The pivotal factors of applying AHP effectively are analyzed in detail.That is to say,the appropriate assessment indexes systems and the principles which can decide the important weights of indexes must be established.Thus,AHP method can be used effectively for selecting a delivery system,which is most suitable for the project. Related Articles | Metrics

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Dynamic Analysis on Vehicle-Road Vertical Coupled System LUO Hong, LIANG Bo, SU Shi-yi 2008, 27(5): 803-805,811.  Abstract ( )   PDF (296KB) ( )   While a vehicle running on the road,the vibration of vehicle is coupled and interacted with the road.The vehicle is simplified into a two DOF vibration system and the road is dispersed to the multi-layer FEM systems.Viewing the road and vehicle as a whole system,each of them is a subsystem of the whole system.Then a model of vehicle-road vertical coupled system is established and the dynamic equilibrium equation of vehicle-road systems are deduced.It provides reference to the further research about interaction and dynamic characters of vehicle-road on highway. Related Articles | Metrics

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Application Actuality of Fractal Theory in Turbulence and Sediment Studies ZHONG Liang, XU Guang-xiang 2008, 27(5): 806-811.  Abstract ( )   PDF (541KB) ( )   Turbulence and sediment problems are the basic topics of river dynamics,as well as the well-known hard-solved problems in hydroscience,for conventional linear mathematic methods have relatively more limitations in solving these non-linear problems.Fractal theory as one of the most important nonlinear science branches provides a new approach to study turbulence and sediment.Based on a large number of research materials at home and abroad,the application actuality of factal theory in turbulence and sediment studies is illustrated systematically and its application prospect is explored. Related Articles | Metrics

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Study of Navigation Condition in the Entrance Area of Approach Channel of Hydro-complex in Wujiang River ZHAO Zhi-zhou, WANG Duo-yin, XU Hong, ZHANG Xing-jiang 2008, 27(5): 812-815.  Abstract ( )   PDF (303KB) ( )   There are many aspects which seriously influence the navigation condition in the entrance area of approach guide channel especially at downstream of hydropower plant of Wujiang River,such as higher head of water,large discharge,and narrow and bent river valley.Taking the hinge of Wujiang River as the prototype,the model of hydro-complex in narrow reach with bend in valley is established.The layout of different approach channels,the influence of guide channel and the skew angle of tail water channel on the navigation condition in the entrance area of lower river are studied.The principle in general configuration of the navigation building with hydrodynamic building is proposed. Related Articles | Metrics

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Study on General Layout of Hydroelectric-Navigation Project of Guojundu in Fujiang River QIU Xi, YIN Chong-qing 2008, 27(5): 816-821.  Abstract ( )   PDF (552KB) ( )   According to the study on hydraulic model tests of Guojundu hydroelectric-navigation schemes,the changes of the sediment despite and navigable flow conditions in the entrance area of upper and lower approaches are discussed.The plane layout of division channel of ship lock,the sailing circumstance and main factor of designing fleets at the upper and lower entrance of approaching channel and the linkage section in different navigable discharge situations are studied.The design of routes in and out ship lock is optimized.The modification of the plane layout of ship lock approach channel is proposed according to the observation on navigation flow condition.And then the recommended plan with better navigational condition,less load of engineering and more stability of bed evolution will be selected out. Related Articles | Metrics

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Study on the Potential Appraisal of Arable Land Consolidation Based on GIS HUANG Hai 2008, 27(5): 822-825.  Abstract ( )   PDF (359KB) ( )   Aiming at the current problems in the analysis of arable land consolidation,the appraisal index for potential analysis is established,including newly-added farmland coefficient,output increase ratio,forest increasing ratio and fields' size increase ratio.Taking the Chejiang Town of Hengnan County,Hunan Province as an example,the procedures of arable land consolidation potential appraisal based on GIS are introduced in detail.The result proves that this method is scientific and feasible. Related Articles | Metrics

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Study on Research Progress of the Mechanism of Urban Sprawl and Spatial Morphology Evolution MU Feng-yun, ZHANG Zeng-xiang 2008, 27(5): 826-830.  Abstract ( )   PDF (455KB) ( )   The mechanism of urban sprawl and spatial morphology evolution are analyzed on the base of urban sprawl and urban evolution manner,and a comprehensive literature review on the progress in the dynamics of the urban sprawl and spatial morphologic is presented.Based on the difference in the theory and aspects the scholars thinking about,all the existing urban sprawl and spatial morphologic methods can be roughly classified into five broad categories: (1) urban economy school; (2) human ecology school; (3) mathematical science school; (4) urban geography school;and (5) landscape ecology school.Each method has its advantages and disadvantages,and can be applied alone or integrated according to the geographical features of the study object. Related Articles | Metrics

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Study on the Best Time for Maintenance of Devices in Different Operation Stages CHI Jie 2008, 27(5): 831-834.  Abstract ( )   PDF (308KB) ( )   By analyzing the rules of devices faults and the maintenance methods,the various maintenance strategies of different stages to improve the operation efficiency are discussed.It is concluded that it is impossible to improve the operation efficiency when preventive maintenances are made during the stages that the faults take place occasionally,that is λ' (t)=0;and as λ' (t)≠0,that is the wearing and initial stages for faults,the best time for maintenance T should satisfy the condition ∫0T (tλ' (t)dt=tp/tf.Additionally,on the basis of the broken-down data of ZW-17/29 Series Air Compressors in service,the suitable time for maintenance T in wearing stages and the relevant maintenance plans are defined. Related Articles | Metrics

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Dynamic Simulation of the Wear of Radial Airproof Patch of Triangle Rotor Engine HE Ze-long, LIU Cheng-jun, ZHANG Mi 2008, 27(5): 835-838.  Abstract ( )   PDF (292KB) ( )   One of the key techniques of the triangle rotor engine is the radial airproof of the rotor.All kinds of state parameters are changing with time when radial airproof patch is wearing in the cylinder.The stress influence to wear is considered and the temperature influence to wear is considered too.The wearing capacity is calculated by simulation technique and a dynamic simulation model of the radial airproof patch wear is established.The simulation program is worked out by UG Grip.The relationship between wearing capacity distribution and the time of the radial airproof patch is gained by the numerical calculation based on the simulation model. Related Articles | Metrics

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New Characteristics and Application of Strictly Pre-invex Functions PENG Zai-yun, WANG Da-cheng 2008, 27(5): 839-842.  Abstract ( )   PDF (300KB) ( )   A new class of important generalized convex functions-prequasi-invex function is further discussed.To improve research on the generalized convex function,some new characteristics of the prequasi-invex function are figured out by means of the cographical set of function (E (f)={ (x,α):x∈K,α∈R,f (x)≤α}) and-invex set,and its two applications in the mathematical programming problem are proposed.So the study of this type generalized convex function becomes further now. Related Articles | Metrics