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中文核心期刊
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中国科技核心期刊
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    Bridge & Tunnel Engineering
    Redundancy Analysis of Half-through Tied Arch Bridge
    ZHU Jinsong1,2, SHENG Rongrong1
    2018, 37(07): 1-8.  DOI: 10.3969/j.issn.1674-0696.2018.07.01
    Abstract ( )   PDF (880KB) ( )  
    In order to reduce the risk of progressive collapse of half-through tied arch bridges caused by local failure, the structural analysis method of applying bridge redundancy to design optimization, operation and maintenance was studied with an example of a typical half-through tied arch bridge. Firstly, the deterministic measures and the deterministic direct analysis method in NCHRP Reports were chosen to carry out the redundancy evaluation. Secondly, the intact model and the damaged models were established using the finite element software ANSYS to obtain the load-deformation curves. Finally, the effect of different damage modes on capacity and functionality of the bridge structure were analyzed as well as the redundancy indices, and suggestions for design optimization, operation and maintenance were offered. The results show that failure of a middle pier bearing next to the arch foot, general suspenders or long suspenders decreases the ultimate capacity of the bridge by about 30%, and that the maximum deflection of the main girder before overall failure decreases by 10% to 30 as well. The redundancy ratio for functionality rf is related to bridge stiffness. The redundancy ratio for ultimate capacity ru is influenced by the bridge failure mode corresponding to the certain loading mode. The redundancy ratio for damaged conditions rd is associated with the boundary conditions of the damaged member in bridge structure. In view of design optimization, stiffness of the middle span deck system and the strength of suspenders should be improved. In view of maintenance, it is advised that the maintenance level be heightened, that the supervision of overloading be strengthened, and that suspenders be specially maintained.
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    Study on Construction Mechanical Properties of Cantilever-Pouring Concrete Arch Bridge
    ZHOU Qian1,2,ZHOU Shuixing1,LI Xiaoqing1,FENG Yushi2
    2018, 37(07): 9-13.  DOI: 10.3969/j.issn.1674-0696.2018.07.02
    Abstract ( )   PDF (766KB) ( )  
    In order to control construction stress and deformation of Cantilever-Pouring Concrete Arch Bridge, the finite element program ANSYS was used to research construction mechanical properties of Cantilever-Pouring Concrete Arch Bridge, mainly analyzing the effect segment length, form of hanging blue structure, and pre-stress and cable anchor position. the results show: segment length and cable anchor position control tensile stress setting pre-stress can effectively reduce stress, but the influence on deformation is not obvious; hanging blue form structure can both control stress and deformation to improve construction stress and deformation, it better to choose front pivot hanging basket construct.
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    Analysis of Shield Tunnel Excavation Surface Stability in Anisotropic Foundations
    LIU Wenjie1, WANG Tonghua2, XIAO Jianxun3
    2018, 37(07): 14-19.  DOI: 10.3969/j.issn.1674-0696.2018.07.03
    Abstract ( )   PDF (678KB) ( )  
    The main stress axis rotation caused by the unloading of the shield excavation plane was taken into account in the “wedge-prism” limit equilibrium model. Based on the Casagrande formula, the limit equilibrium solution of the limit support pressure of shield excavation in anisotropic foundation was deduced. Finally, the influence of each calculation parameter on the limit support pressure was analyzed by examples. The results are shown below: the limit supporting pressure of tunnel surface decreases linearly with the increase of the anisotropic ratio k, and it would be unsafe to ignore the anisotropic of strength, especially when the anisotropic ratio k is less than 1; While the k is more than 1, the limit supporting pressure of tunnel face would decrease first with the increase of cover-to-diameter ratio C/D and then tend to be constant contrary to what happened when k is less than 1. Furthermore, the variations of the limit support pressure along with the increase of C/D will be more obvious as the strength of soil shows much more significant anisotropic properties; the limit support pressure of tunnel face decreases linearly along with the increase of cohesion and decreases nonlinearly with the increase of internal friction angle.
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    3D Numerical Simulation of Chengdu Metro Line 4 Undercrossing Railway Bridge
    FANG Shitao
    2018, 37(07): 20-27.  DOI: 10.3969/j.issn.1674-0696.2018.07.04
    Abstract ( )   PDF (2316KB) ( )  
    The second phase of interval tunnel of the Chengdu metro line 4 is a two-line shield tunnel. It crosses a railway group, which includes ballastless track, ballast track and pile foundation railway bridge. Using a numerical simulation method, a 3D finite difference model of shield tunnel crossing railway bridge was built. Surface subsidence, soil deformation, and pier displacement caused by tunnel construction were analyzed in detail. The safety of the railway bridge was evaluated, and control measures were put forward. Based on soil reinforcement measures, two cases of a reinforced and non-reinforced soil mass were compared. The results show that the maximum horizontal displacement and vertical subsidence can be reduced by 58% and 79% after soil reinforcement, and that the values of settlement meet the safety requirements if the soil mass is reinforced.
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    Highway & Railway Engineering
    Research on Image Method of Measuring Characteristics of Concrete Surface Structure
    KONG Lingyun1,2, SUN Rui2, LI Jinqiao2, LIU Xiaoxia3
    2018, 37(07): 28-32.  DOI: 10.3969/j.issn.1674-0696.2018.07.05
    Abstract ( )   PDF (1843KB) ( )  
    In order to provide more convenient and accurate measurements of characteristics of concrete surface structure, based on the data of Shantou-Zhanjiang expressway in Guangdong province, rapid sampling by means of digital image processing technology and analysis and calculation in late stage was realized. And the influences of illumination, shooting angle and distance, image processing calculation rule and the cleanliness of concrete surface on the measurement results were also studied. The results show that filtering and denoising should be carried out before the surface structure characteristics of the concretes initial image are identified. When shooting angle is frontal, shooting distance has little effect on the gray value. With the increase of illumination,the gray value increases first and then decreases. Debris on the surface of concrete will be reflected on the image, thus interfering with the judgement of the characteristics of concrete surface structure. Therefore, the appropriate illumination should be selected through experiments, and maintain stability throughout the process. At the same time, the surface of the measured concrete should be kept clean.
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    One-dimensional Concretion for Settlement of Subgrade of Unsaturated Soft Soil Under Different Boundary and Initial Conditions
    YIN Ke1,2, YAO Shunyu2, GU Yangyang2, JIANG Daoxu2
    2018, 37(07): 33-39.  DOI: 10.3969/j.issn.1674-0696.2018.07.06
    Abstract ( )   PDF (745KB) ( )  
    To calculate the settlement, the Kelvin creep model and the Duncan no-linear model in series were installed as a new model to describe the settlement and creep. The model was combined with governing equations of pore water and pore air and a new consolidation theory of unsaturated soil was obtained, including the creep of subgrade. The equations used can be used to get values of pore water and pore air at any place and time. The consolidation-creep theory was applied to engineering to verify that the correctness and the test results were consistent with the conclusion. Using the proposed unsaturated soft soil theory, the influence of the soft soil roadbeds boundary conditions on the consolidation speed was explored. It was found that boundaries with better permeability are advantageous to complete the dissipation of pore pressure as soon as possible and accelerate the process of consolidation. Pore pressure is not necessarily monotonically decreasing in the process of consolidation of unsaturated soft soil and negative pore water pressure could occur in the process of consolidation.
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    Analysis of Damage of Rubber Concrete in Freezing-thawing Circumstance
    GUO Qi,CUI Shengchao,WU Han
    2018, 37(07): 40-45.  DOI: 10.3969/j.issn.1674-0696.2018.07.07
    Abstract ( )   PDF (637KB) ( )  
    In order to reveal the damage law of rubber concrete under the effect of the freeze-thaw cycle, three volumes (10%, 20%, 30%) of rubber powder with particle size (20,40,80 mesh) were made of concrete for a rapid freezing and thawing test with ordinary concrete. The mass loss rate and the amount of freezing and thawing injury were selected for analysis. The results show that the particle size of the rubber powder has little effect on the mass loss rate at low dosage (10%) and is inversely proportional to the mass loss rate at higher content (20%, 30%).It also shows that the amount of freezing and thawing injury is inversely proportional to the volume of rubber powder under the same particle size, but the (30%-80 mesh) rubber powder is repelled by this method. The comprehensive analysis shows that the best content and the best particle size of the rubber power for rubber concrete based on frost resistance is 30%-20 mesh when the content is 10%~30% and the particle size is 80~20 mesh.The relationship between the mass of rubber concrete and the number of freeze-thaw cycles was obtained by regression analysis. Based on the verification of the model of concrete freeze-thaw damage, a quadratic equation model was given,which laid the foundation for quantitative analysis of the freeze-thaw damage of rubber concrete.
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    Research on Aging-Resistance Performance of UHPC-TPO Composite Component Based on Simulated Natural Conditions
    LI Jia1,2, ZHAO Zhao1, WANG Wanpeng1, CHEN Wei1
    2018, 37(07): 46-53.  DOI: 10.3969/j.issn.1674-0696.2018.07.08
    Abstract ( )   PDF (922KB) ( )  
    In order to investigate the influence of environmental factors on the aging-resistance performance of UHPC-TPO (ultra-high performance concrete and thin polymer overlay), different environment conditions were simulated, such as “UV irradiation”, “UV irradiation +water soaking”, “UV irradiation +10%NaCl solution immersion”, and “UV irradiation + high temperature”. After the environmental simulations, pull-off tests and shear tests were carried out to analyze the effects of environmental conditions on the mechanical properties of the interlayer between UHPC-TPO. Water-penetration tests and surface structural depth tests were carried out to study the effects on the road performance in areas such as water permeability and surface roughness. According to the degree of influence on the bond strength, the order of the environmental factors are as follows: “UV irradiation + high temperature”>“UV irradiation +10%NaCl solution immersion”>“UV respectively, and the shear strengths are 10.32 MPa, 9.95 MPa, 9.18 MPa, and 8.59 MPa respectively. Moreover, the influence of the environment on water permeability and surface structure depth can be ignored for UHPC-TPO.
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    Port & Waterway · Hydraulic & Hydroelectric · Resources & Environment
    Hydraulic Model Study on Filling-Emptying System of Top Outlet Long Culvert in Ship Lock Bottom at Congjiang Ship Lock
    ZHOU Jiayu, XU Kui, CHEN Liang, ZHANG Xujin
    2018, 37(07): 54-59.  DOI: 10.3969/j.issn.1674-0696.2018.07.09 从江船闸闸底长廊顶缝出水输水系统
    Abstract ( )   PDF (975KB) ( )  
    The filling-emptying system of the top outlet long culvert in the ship lock bottom with cover plate energy dissipation was adopted at Congjiang ship lock of Duliujiang navigation-power junction. In order to make the design more reasonabe, a hydraulic model study on the filling-emptying system of the Congjiang ship lock was carried out to investigate the application effect of the filling-emptying system on the medium and high water head scattered ship lock. By comparing the hydraulic characteristics of the ship lock at the filling and discharging, resistance coefficient and hydraulic pressure of lock chamber, flow state and mooring conditions of the ship, it was found that the filling-emptying system of the top outlet long culvert in the ship lock bottom with cover plate energy dissipation has the advantages of reducing the resistance coefficient of the water delivery system, shortening the water delivery time, improving the parking conditions of the gate chamber, reducing the siltation of the suspension chamber, and reducing the difficulty of the construction of the water delivery system, which can meet the safety requirements of high-head shiplocks and supply a reference for similar ship lock designs.
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    Study on Composition and Fractal Characteristics of Geological Particles in Xigeda Formation
    XIANG Guifu1,2,XU Mo1,CUI Jie2
    2018, 37(07): 60-63.  DOI: 10.3969/j.issn.1674-0696.2018.07.10
    Abstract ( )   PDF (364KB) ( )  
    The granule structure and particle size gradation curves of each rock were obtained by sieving rock particles such as sandstone, argillaceous siltstone, silty mudstone, and mudstone in Xigeda strata. The fractal dimensions of rocks in the Xigeda formation were determined using the fractal theory. The dimensions coefficients and the non-uniformity coefficients Cu, the coefficients of curvature Cc, and the water content of the fillers were established ω(%), dry density ρd(g/cm3). The results show that there is a good correlation between the fractal dimension of the particles and the engineering performance of the filler. Therefore, the engineering suitability of the filler can be determined by the fractal dimension of the filler particles.
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    Rock Structures Analysis from GPR Radargram Based on Subspace Method
    ZUO Jie1, OU Jiali1, LIU Jinlian2
    2018, 37(07): 64-68.  DOI: 10.3969/j.issn.1674-0696.2018.07.11
    Abstract ( )   PDF (1237KB) ( )  
    Ground penetrating radar was taken as a feasible remote sensing tool for surveying subsurface geo-structure. This structural information was recorded in radar signal profiles by means of echo signal detection, amplitude, and phase estimation. Besides the energy attenuation and absorption of GPR EM pulse during its propagation into the subsurface from a transmitting antenna, the strong interferences, clutters, background scatters, random noises, and multiples often make the weak signal of structure signatures hardly distinguishable. Furthermore, detecting fractures with multiple signal classifications on subspace is difficult. With experimental field surveying data, it is illustrated that this method can achieve efficiently sparse representation of subsurface structure and yields discriminative fracture signatures for geological interpretation.
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    Traffic & Transportation Engineering
    Research on Influencing Factors of Drivers Reaction Time Based on AHP
    ZHANG Zhiyong, JIA Jianlin, ZHANG Dandan, LIANG Tianwen
    2018, 37(07): 69-75.  DOI: 10.3969/j.issn.1674-0696.2018.07.12
    Abstract ( )   PDF (520KB) ( )  
    Drivers reaction times are an essential parameter to study driving behavior. There are many factors influencing drivers reaction times, but few studies have been conducted on the differences between these factors. Correctly judging the importance of each influencing factor is conducive to improve the forewarning distance model of any driver assistance system. Thirteen influential factors were chosen through analysis of drivers reaction times, including the drivers own factors, road conditions, and traffic environment. Based on a questionnaire survey, three criterion and thirteen indictors of the influential factor of drivers reaction times were prioritized using the analytic hierarchy process (AHP), and the weight vector of the importance was put forward. Among the criterion, drivers own factors possess the largest weight, the final weight of which was 0.637. Among the thirteen indicators, weather conditions have the largest weight, which was 0.252. Driving experience was subordinate to weather conditions, with a weight of 0.203. Through the driving stimulation platform, the research shows that the results are in agreement with the conclusions drawn by the AHP method.
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    Research on Fault Location Method of ITS
    LIU Zunmin1, LIU Qingyuan2, QU Dayi1, CHEN Xiufeng1,3
    2018, 37(07): 76-79.  DOI: 10.3969/j.issn.1674-0696.2018.07.13
    Abstract ( )   PDF (377KB) ( )  
    In order to solve the problem of high false alarm rates and large workloads in the operation and maintenance management system of ITS, an accurate fault location method based on double link was proposed. A new adaptive threshold method was used to pre-judge the fault of the system, and if this threshold was exceeded, a failure diagnosis procedure was started. By developing network link threads and data-adapter link threads, multi-dimensional diagnoses for the hardware and software system can be made to retreive precise locations of faults in ITS. This method was applied in the intelligent traffic operation and maintenance project, and the results show that this method has high accuracy, a low false alarm rate, less manual participation, and meets the application requirements.
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    Research on Traffic Characteristics of Small Spacing Between Interchanges Based on GIS Technology
    CHEN Kuanmin, TIAN Tian, XIA Lipin
    2018, 37(07): 80-84.  DOI: 10.3969/j.issn.1674-0696.2018.07.14
    Abstract ( )   PDF (691KB) ( )  
    ArcGIS technology was used to analyze the GPS data of short distance interconnection between interchanges on the expressway. The longitudinal velocity distribution characteristics of the small-interval interweaving zone and the influence of the sub-confluence zone on the main traffic flow in conclusion were researched. Firstly, the ideology of continuous segment analysis was proposed, and the range of influence of small spacing was defined by the average speed of each unit road segment and the standard deviation of each sample speed in a unit road segment. Then, GPS data with the condition of small spacing on the East Third Ring Road and Ring Expressway of Xi'an was analyzed. The results show that:within the range of exits and entrances of short distance intercommunication, the traffic flow speed is affected by the traffic volume, and the larger the traffic flow is, the smaller the traffic flow rate is; the decrease amplitude of the velocity relative to the main line is basically stable, which has little relation with the traffic volume; the influence degree of the shunt vehicle in the shunt area is greater than that of the confluence area, which is reflected in the range of the speed drop and the influence distance to the flow of main line.
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    Transit Signal Priority Method Based on Schedule Under Connected Vehicle Environment
    BAI Haijian,REN Guixiang,DONG Ruijuan,WEI Liyang
    2018, 37(07): 85-91.  DOI: 10.3969/j.issn.1674-0696.2018.07.15
    Abstract ( )   PDF (467KB) ( )  
    In order to improve bus punctuality rates, considering the location of the vehicle can be known in the network traffic environment, the priority traffic strategy selection model was established according to bus travel times and the time forecast to reach the intersection. At the same time, a new timing scheme was generated according to the time the bus arrives at the parking line, the length of the delay time, and the location of the green light at the arrival time. Finally, it is shown by simulation and calculation: the average punctuality rate of the bus can be increased by 26.67%, the total average travel time reduced by 27.41%, and a small increase of social vehicle delays can significantly reduce the average bus delay at intersections.
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    Predictive Study on City Taxi Scale
    REN Qiliang, SU Lixiao, WU Lixia, JIN Lei
    2018, 37(07): 92-99.  DOI: 10.3969/j.issn.1674-0696.2018.07.16
    Abstract ( )   PDF (495KB) ( )  
    By analyzing the factors of the development scale of city taxis, based on the analysis of the advantages and disadvantages of the modified system dynamics model and the real load rate control method, the two methods were combined. Then,combined with the Chongqing city 2011—2015 and rental car development related data, the system dynamics model parameters were obtained. Meanwhile, three kinds of prediction method were applied to examine 2011—2015 taxi ownership. The results show that the combination forecasting model prediction accuracy is higher than that of the system dynamics model, and the actual loading rate control method.This indicates that the combination forecasting model is effective and feasible, and has important reference value to determine the reasonable scale of city taxis.
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    Spatial Distribution Programming Method of ADS-B Ground Station Oriented to Low Altitude Flight Safety
    QIN Rui1,SHI Yaqi2,WANG Mingke3
    2018, 37(07): 100-105.  DOI: 10.3969/j.issn.1674-0696.2018.07.17
    Abstract ( )   PDF (1124KB) ( )  
    In order to improve the efficiency of layout planning and construction of ADS-B ground station and flight safety assurance capability in low altitude airspace, the basic principles of ADS-B ground station spatial layout on the basis of signal coverage mode, which is constructed according to ADS-B minimum property standard, was made clear. After that, the ADS-B ground station spatial distribution programming method was put forward. With ADS-B ground station spatial layout in Chongqing city as an example, the research shows that the ADS-B ground station spatial distribution programming method can provide valid evidence for layout planning and construction of ADS-B ground stations.
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    Quay Crane Scheduling with Yard Operation Balance at Automated Container Terminal
    DING Yi, ZHANG Qiong, LIN Guolong
    2018, 37(07): 106-112.  DOI: 10.3969/j.issn.1674-0696.2018.07.18
    Abstract ( )   PDF (541KB) ( )  
    In order to solve the the problem of unbalanced workloads of yard blocks in the quay crane scheduling, by considering such factors as quay crane collision, safe distance, and workload balance of yard blocks, a mixed integer programming model for the multiship quay crane scheduling problem (QCSP) at automated container terminal was established, aiming to minimize the make-span of each vessel and balance the workload of yard blocks in each time period. CPLEX software was used to solve this problem. In the case study, in order to further study the effect of the workload balance of yard blocks on the QCSP, a comparison of the two scheduling schemes was carried out by relaxing the balance constraint. The results show that considering the workload balance of yard blocks in the QCSP is helpful to shorten the total operation time, and in each time period, there are different degrees of reduction in workload imbalance degree of yard blocks, ranging from 2% to 15%, which confirm that the model is effective in balancing and optimizing the workload of yard blocks in the QCSP.
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    Vehicle &Electromechanical Engineering
    Research on Hydrodynamic Forces on Ship in Oblique Motion Based on Numerical Analysis
    LIAN Jingjing1, YANG Xiao1, YIN Yong2
    2018, 37(07): 113-117.  DOI: 10.3969/j.issn.1674-0696.2018.07.19
    Abstract ( )   PDF (1595KB) ( )  
    The hull form KVLCC2 (KRISO Very Large Crude Carrier) model tanker was considered by the ITTC maneuvering technical committee in a comparative study of ship maneuverability. The incompressible viscous flow around KVLCC2 was investigated using a classical RANS (Reynolds Averaged Navier-Stokes) equation. The numerical simulation around KVLCC2 in oblique motion was carried out. The longitudinal force coefficient and lateral force coefficient and yaw moment coefficient were gained under different drift angles. The pressure coefficient distribution and vorticity flow distribution on the hull surface were also obtained. Compared with the experimental data, the result had a good agreement. At the same time, the hydrodynamic derivatives in ship maneuvering equations were calculated by least square curve fitting. The result shows that the accuracy of numerical calculation results can meet engineering demands.
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    Resistance Prediction of Inland Ships Based on SHIPFLOW
    YANG Jingdong, LIU Yongzhen, LEI Lin
    2018, 37(07): 118-122.  DOI: 10.3969/j.issn.1674-0696.2018.07.20
    Abstract ( )   PDF (525KB) ( )  
    The SHIPFLOW software was used to simulate the flow field around inland ships, while the resistance prediction of ships, with the fluid viscosity and the effects of free surface, were taken into account. Three kinds of hull grid (CC, MM, MF) were adopted. The theory of potential flow and viscous flow ZONAL method was applied. The results of the numerical calculation and the results of the Ayre method were compared to estimate the total resistance. The calculation results show that the most accurate results, as well as the meshing form MM, validate the reliability of SHIPFLOW software to solve the technology and improves conversion efficiency. Finally, the MM grid form was selected to prediction the resistance of the ship.
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