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20 August 2021, Volume 40 Issue 08 Previous Issue   
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Transport+Big Data and Artificial Intelligence
Transportation Infrastructure Engineering
Transportation Equipment


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Transport+Big Data and Artificial Intelligence

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Competitiveness Evaluation and Development Suggestions for Ports Based on Evidence Theory XIE Xinlian, ZHU Yunqi, TIAN Cong 2021, 40(08): 1-6.  DOI: 10.3969-j.issn.1674-0696.2021.08.01 Abstract ( )   PDF (561KB) ( )   The port is the core of the maritime ecosystem, and evaluating competitiveness of the port is helpful to grasp the competitive advantages and disadvantages of port, so as to enhance the competitiveness of port and marine ecosystem. Port competitiveness evaluation is a complex multi-attribute evaluation problem. Based on the deep analysis on the influencing factors of port competition, a port competitiveness evaluation index system considering the integration development of city and port was designed. The standard deviation rate was used to determine the weight of the index, and the evidence theory was used for evaluation information integration, so as to realize the evaluation of port competitiveness. Taking Dalian Port and Shanghai Port as examples, the evaluation results of the competitiveness of the two ports were obtained through programming calculation, and the causes influencing Dalian port and Shanghai port competitiveness level growth driving force was further explored, which provided corresponding suggestions to make up for the short board of the competitiveness development. References | Related Articles | Metrics

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Evaluation of Traffic and Environmental Benefits for the Mixed Traffic Flow of Autonomous Vehicles HU Mingwei1,2,3, SHI Xiaolong1, ZHAI Suyun4, LIU Peng1 2021, 40(08): 7-14.  DOI: 10.3969-j.issn.1674-0696.2021.08.02 Abstract ( )   PDF (904KB) ( )   In order to explore traffic and environmental benefits of the mixed traffic flow of autonomous vehicles, a comprehensive simulation system of driving behavior based on autonomous vehicle was established by use of microscopic traffic simulation tool VISSIM and MOVES emission model. The simulation model of the operation process of autonomous vehicles with different market penetration rate was studied. Considering different traffic flow levels (peak period, flat peak period and low peak period), total travel time, average speed, average parking times and average delay were selected as traffic benefit evaluation indexes, and PM2.5, NOx, CO emission and energy consumption were selected as environmental benefit evaluation indexes. The research results show that the traffic and environmental benefits of the mixed traffic flow increase with the market penetration rate rising of the autonomous vehicles. Moreover, the traffic and environmental benefits during peak period is better than those during flat peak period; the traffic and environmental benefits during flat peak period is better than those during low peak period. Taking traffic benefits as an example, in peak period, when the proportion of autonomous vehicles reaches 100%, the total travel time can be reduced by 45.59%, the number of stops can be reduced by 98.77%, the average delay can be reduced by 96.46%, and the average travel speed can be increased by 122.73%. During the flat peak period, the average delay can be reduced by 84.43% and the number of stops can be reduced by 86.42%; during the low peak period, the total travel time is only reduced by 1.62% and the the average travel speed is increased by 1.03%. References | Related Articles | Metrics

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Influence of the Opening of High-Speed Rail on the Accessibility and Spatial Equity of Chengdu-Chongqing Urban Agglomeration MU Fengyun, HUANG Qi, YANG Meng, LI Qiuyan, CHEN Lin 2021, 40(08): 15-24.  DOI: 10.3969-j.issn.1674-0696.2021.08.03 Abstract ( )   PDF (15087KB) ( )   Taking Chengdu-Chongqing urban agglomeration as the research object, the influence of the opening of high-speed rail on Chengdu-Chongqing urban agglomeration was discussed from the perspective of efficiency and fairness. Firstly, with average travel time and weighted average time as input indicators and daily accessibility and economic potential as output indicators, the accessibility level of Chengdu-Chongqing urban agglomeration was analyzed from different aspects. Secondly, DEA model was used to construct comprehensive accessibility index to analyze the influence of high-speed rail opening on the accessibility efficiency of Chengdu-Chongqing urban agglomeration. Finally, based on the comprehensive accessibility index, the variation coefficient and Spearman coefficient were calculated to reflect the influence of the opening of high-speed railway on the spatial equity of Chengdu-Chongqing urban agglomeration. The research shows that: After the opening of high-speed railway, the accessibility level of Chengdu-Chongqing urban agglomeration has increased significantly, the economic attraction capacity of cities within Chongqing has been significantly improved, and cities within Sichuan province have more development opportunities and greater economic benefits. The accessibility efficiency of cities within Chongqing is obviously better than that of cities within Sichuan Province. The spatial pattern of accessibility efficiency of Chengdu-Chongqing urban agglomeration shows the distribution trend of “core-periphery”. The hinterlands of the main urban area of Chongqing and Chengdu, two major growth poles, are expanded, and the connections between and within the two economic circles are strengthened. The opening of high-speed railway has caused “corridor effect” and “spatial polarization effect”, which has aggravated the unfairness of development between stations and non-stations, within and between the two economic circles. References | Related Articles | Metrics

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Rollover Warning Study of Heavy Vehicle Based on AdaBoost Algorithm ZHU Tianjun1, MA Wei1, WANG Zhenfeng2,3, YIN Xiaoxuan1 2021, 40(08): 25-33.  DOI: 10.3969-j.issn.1674-0696.2021.08.04 Abstract ( )   PDF (3674KB) ( )   Aiming at the problem that the rollover of heavy vehicles couldnt be predicted accurately under complicated driving conditions, an AdaBoost algorithm based on machine learning was designed, which realized the real-time and accurate calculation of non-trip rollover criterion of heavy vehicles under complex driving conditions. Firstly, the heavy vehicle simulation model and rollover warning model were established. Secondly, based on the AdaBoost learning algorithm theory, the architecture of multiple weak classifiers based on the single-layer decision method was designed, and the simulation training and weighted summation were carried out. Finally, combined with commercial software TruckSim dynamics software, the rollover effect of heavy vehicle rollover warning failure under double lane change (DLC) and fishhook conditions was compared and analyzed. The simulation results show that the proposed rollover warning criterion based on AdaBoost algorithm can effectively predict heavy vehicle rollover under complex driving conditions, the accuracy of the corresponding test set is 24.9% better than that of Logistic regression algorithm, and the receiver operation characteristic (ROC) curve area is 0.958. References | Related Articles | Metrics

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Meso-level Safety Analysis Model of Urban Arterials in Dense Road Network LI Jia1, WANG Xuesong2 2021, 40(08): 34-41.  DOI: 10.3969-j.issn.1674-0696.2021.08.05 Abstract ( )   PDF (1685KB) ( )   The traditional safety analysis model was established at the micro level, which decomposed the adjacent intersections and road sections into two independent research units to study. In dense road network, the distance between intersections of urban arterials was small, and the traffic operation of adjacent sections and intersections affected each other, so it was difficult to divide sections and intersections. Intersection spacing and road network morphology on both sides of the road were important factors affecting the safety of urban arterial. The traditional model studied the road section and intersection accidents respectively, which could not analyze the impact of these two factors on the overall safety of the urban arterial. Based on 21 urban arterials in Shanghai, the adjacent sections and intersections were combined into 118 meso-units according to the road cross-section and traffic operation characteristics, and the road network morphology of the roads on both sides of the meso-units was calculated. Considering the correlation between geometric design and traffic characteristics of meso-units from the same urban arterial, a negative binomial model with random effects was established. The influence of intersection spacing and road network morphology on the safety of urban arterial was analyzed. The results show that compared with irregular grid road network and mixed road network, the number of accidents of urban arterial in grid road network is less; the longer the distance between intersections, the less the accidents on the main road. The meso-level analysis method overcomes the problems of unit division and influencing factor analysis in traditional safety analysis model, and provides suggestions for urban arterial design and road network planning. References | Related Articles | Metrics

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Pricing of Urban Rail Transit Peak Fare Based on Evolutionary Game Theory JIAO Liudan1, ZHU Yinghan1, WU Ya2, SONG Xiangnan3 2021, 40(08): 42-49.  DOI: 10.3969-j.issn.1674-0696.2021.08.06 Abstract ( )   PDF (926KB) ( )   It is very important for the sustainable development of urban rail transit to accurately measure the time and space value of urban rail transit and ground bus during peak hours and establish reasonable urban rail transit fares. Through constructing the evolutionary game model of group members’ choice of urban rail transit and ground bus in peak hours, the pricing of urban rail transit fares was studied and analyzed with Chongqing as an example. The results show that the urban rail transit passenger flow can be effectively controlled to a certain extent by the basic fare of 4 yuan with an increase of 2 yuan. Furthermore, the sensitivity analysis of urban rail transit passenger flow and ticket price was carried out. It is found that in the case of the same fare change range, the farther the travel distance is, the greater the passenger flow variation is. With the increase of travel distance, the difference of passenger flow change amplitude increases significantly. References | Related Articles | Metrics

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Optimizing Timetable for Urban Rail Transit Network during the First Train Time Period YANG Jiqin1, TIAN Qin2, XU Zhandong2, LEI Li3 2021, 40(08): 50-56.  DOI: 10.3969-j.issn.1674-0696.2021.08.07 Abstract ( )   PDF (753KB) ( )   The passenger flow law of the first trains time period in urban rail transit is different from that of any another time periods. The train transfer connection scheme and timetable can be formulated according to the passenger flow law during the time period, which can improve passenger transfer efficiency and reduce transfer waiting time. Based on the simplified network topology, the optimization model of timetables in the first trains time period was developed, whose objective was to minimize the cost of waiting time for passengers to transfer and the cost of departure, considering passenger and operation aspects. The genetic algorithm was used to solve the proposed model. Finally, the validity of the proposed model was verified by the passenger flow of the first trains time period in Shenzhen metro network. The results show that the optimized first train schedule reduces the cost of waiting time for passengers to transfer and the cost of train departure, which can provide a basis for making the first train schedule. References | Related Articles | Metrics

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Optimization Model of Emergency Bus Dispatching Considering Vehicle Arrival Time Window ZHA Weixiong, FENG Tao, YAN Lixin 2021, 40(08): 57-62.  DOI: 10.3969-j.issn.1674-0696.2021.08.08 Abstract ( )   PDF (2261KB) ( )   In view of the long-term service interruption of urban rail transit lines, considering the type of emergency bus and the arrival time window of vehicles comprehensively, the transportation organization scheme was established by using the ground emergency bus. Through the restriction of the vehicle arrival time window, the unreasonable dispatch schemes were effectively rejected, and then the rescue time of the emergency bus, the vehicle carrying capacity, the number of vehicles dispatched and the number of round trips were taken as the restriction conditions to establish an optimization model of emergency bus dispatching with vehicle arrival time window, and the improved genetic algorithm was used to solve the proposed model. Finally, the simulation analysis on Nanchang Metro Line 2 was carried out. The results show that the convergence accuracy and search ability of the improved genetic algorithm are better than those of the general genetic algorithm, and the optimized model can effectively improve the evacuation efficiency of emergency public transport. References | Related Articles | Metrics

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Dynamic Planning Method of Customized Bus Routes for Passenger and Freight Sharing in Weak Passenger Flow Areas BAI Haijian, WANG JUN, ZHONG Jianfeng, WEI Liyang 2021, 40(08): 63-70.  DOI: 10.3969-j.issn.1674-0696.2021.08.09 Abstract ( )   PDF (1780KB) ( )   Aiming at the problem of difficult bus operation in the areas with weak passenger flow, based on the analysis of the traffic characteristics of typical areas with weak passenger flow, the operation goal of replenishing passengers with goods and win-win for both passenger and freight was realized, through the application of passenger and freight sharing transportation mode and the dynamic customization of public bus dispatching method. Firstly, the dynamic and static passenger and freight customization requirements were classified and the customization requirements were processed in stages. Then, with the goal of minimizing the total transportation time, the initial route optimization model of customized bus was constructed by considering the constraints such as capacity and customized demand time windows. On the basis of this, considering the time window constraints of initial passengers and dynamic demand, the dynamic route optimization model of transit bus was constructed and the response mechanism of dynamic customized demand was established, so as to realize the dynamic planning of passenger and freight sharing customized bus routes. Finally, the feasibility of the proposed model was illustrated through an example and compared with the non-mixed transportation model. The results show that under the same transportation demand conditions, the number of vehicles required by the proposed model is 2 less than that of the non-mixed model, the satisfaction rate of dynamic demand is increased by 16.7% and the total no-load rate is reduced by 12.4%. References | Related Articles | Metrics

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Key Node Identification Algorithm of Railway Freight Transportation Network LIU Jie 2021, 40(08): 71-77.  DOI: 10.3969-j.issn.1674-0696.2021.08.10 Abstract ( )   PDF (2367KB) ( )   In order to improve the safety of railway freight transportation network, the importance of railway freight station was analyzed scientifically and rationally. Considering the freight stations as nodes, the goods delivery business between freight stations was abstracted as edge and transfer actions and a transportation network of goods was formulated. On this basis, the PageRank algorithm was applied to compute and obtain the importance time series sample of each station. Then, the importance of each station was abstracted as a random variable, and Gaussian mixture distribution was used to fit the importance samples to get the importance distribution function of each station. Finally, the mean value of the distribution function was taken as the measuring value of importance. A case study of Chengdu Railway Bureau Co., Ltd., was carried out to calulate. The results show that the average importance of the first-class, second-class, third-class and fourth-class stations is 4.59, 2.99, 4.24 and 2.76 respectively, which indicates that the first-class station and the third-class station are the most important station clusters in the network. Xiaozhaiba, the third-class station, is the most important node in the network and its importance value is 118.28, which is consistent with the actual data statistical analysis results. The effectiveness of the proposed method is verified. References | Related Articles | Metrics

Transportation Infrastructure Engineering

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Review on the Research Status of Air Pollutant Emission in Port Area in the Development of Green Port HE Linlin1, 2, 3, JIAO Yuqi1, 2, 3, JIA Rui1, 2, 3, LIANG Yue1, 2, 3 2021, 40(08): 78-87.  DOI: 10.3969-j.issn.1674-0696.2021.08.11 Abstract ( )   PDF (3278KB) ( )   China has the largest number of ports with container throughput more than one million TEUs in the world. The issue of air pollutants caused by ships and handling facilities is becoming more and more serious at the same time that the ports have achieved good economic benefits. In order to implement the concept of sustainable development of ports, it is imperative to construct green ports. Through analyzing and studying the domestic status such as the sources of air pollutants, the compilation method of emission inventory and the emission characteristics of air pollutants, the main sources of air pollutants during port construction and operation were summarized. In order to expound the air pollutant emission inventory of port ships, two main air pollutant detection methods such as point type air quality automatic detection method and PEMS were briefly introduced; the compilation methods and current situation of emission inventory of port transport ships, cargo handling equipment and collection and distribution vehicles were summarized; moreover, the characteristics of air pollutant emission from the main pollution sources of the ports were summarized. Finally, the concept and expression of air pollution factor of port ships were proposed to compare the emission characteristics of ship air pollutants and evaluate the effectiveness of ship emission reduction in different years and different regions. The domestic research status of air pollutant emission was analyzed and the current deficiencies in the study of air pollutant emission inventory were pointed out, such as insufficient attention on inland ship emissions, lower localization of emission factors and incomplete consideration of the sources of air pollution in the port. References | Related Articles | Metrics

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Dynamic Response and Damage Analysis of Double-Column Bridge Impacted by Falling Stone PU Wanli1, LIN Changsheng1, WANG Chen2 2021, 40(08): 88-96.  DOI: 10.3969-j.issn.1674-0696.2021.08.12 Abstract ( )   PDF (4107KB) ( )   In order to study the dynamic response and damage of double-column bridge in mountainous area impacted by rockfall, a double-column bridge in western mountainous area was taken as the research object. LS-DYNA was used to establish a high-precision three-dimensional solid collision finite element model. The influence of rockfall parameters on the bridge dynamic response and damage was analyzed, and the time-history curve of impact force of pier was discussed and compared with the calculation formula of equivalent impact force given by various national norms. The research results show that the damage caused by rockfall impacting the middle of bridge pier is larger than that of other locations; the influence of rockfall velocity on the peak value of impact force is more significant, and the influence of rockfall mass on the duration of impact force and the maximum horizontal displacement is more significant when the pier is impacted. Besides, the damage degree of bridge pier increases with the increase of kinetic energy of falling stone, while the damage degree of rockfall mass to the damage degree of bridge pier is more significant; moreover, with the increase of rockfall mass, the damage form of pier tends to be more inclined to shear damage of oblique section. The calculation results of the impact force calculation formula of “Specifications for Design of Highway Subgrades” and “Technical Manual of Railway Engineering Design” in China are relative small, and the design is not very safe. The calculation results of the Japan Highway Public Corporation formula are in good agreement with the peak values of impact force of numerical simulation, which is recommended for engineering design. References | Related Articles | Metrics

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Seismic Performance of Locally Corroded RC Rectangular Pier under Non-orthogonal Horizontal Loads ZHANG Zhongfan1, JI Shilei1, SUN Jinsheng1, TAN Zhendong1, JIA Chenghan2, HUANG Haixin2 2021, 40(08): 97-105.  DOI: 10.3969-j.issn.1674-0696.2021.08.13 Abstract ( )   PDF (2554KB) ( )   The finite element model of the corroded reinforced concrete (RC) bridge pier was established and verified by combining OpenSees software with the existing experimental data. Based on this, the effects of different corrosion positions and non-orthogonal loading angles on the seismic performance of RC piers were investigated through quasi-static loading and dynamic time-history analysis. The results show that the seismic performance degrades significantly when the corrosion position is close to the plastic hinge area at the bottom of the pier, and the deterioration of the performance decreases rapidly after the corrosion position moves up. Under quasi-static action, with the loading angle tending to strong axis, the yield load and maximum lateral load of RC piers increase obviously; the ductility increases and the hysteretic energy dissipation capacity enhances significantly. On the contrary, when the loading angle is closer to the weak axis, the maximum lateral load and displacement ductility coefficient are obviously affected by corrosion and the degradation is even more severe. Under the action of ground motion, when corrosion occurs at the bottom of the pier, the maximum displacement angle at the top of the pier is the largest and the maximum shear force and bending moment at the bottom of the pier are the smallest. With the moving up of corrosion position, the maximum displacement angle decreases and the bending and shear strength increases. When the input angle of ground motion deviates from the weak axis to the strong axis, the maximum displacement angle at the top of the pier decreases, the maximum shear force and bending moment at the bottom of the pier increases, and the increase of the bending strength is larger than that of the shear strength. The research results can provide a theoretical basis for the seismic performance evaluation of corroded RC piers in service. References | Related Articles | Metrics

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Loading Test of Locally Reinforced Embankment WANG Zongjian1, 2, CHEN Bo3, YAO Yun1, Waoki Tatta4, WANG Shuo1 2021, 40(08): 106-113.  DOI: 10.3969-j.issn.1674-0696.2021.08.14 Abstract ( )   PDF (6800KB) ( )   In order to control the slip surface of the embankment, a locally reinforced embankment structure in which reinforcements were laid in the middle and upper part of the embankment was designed. Selecting dry sand as the filler and nylon mesh as the reinforcement, a self-made model test box was used to prepare four kinds of embankment models such as non-reinforced, full-section reinforced, 3-layer locally reinforced and 4-layer locally reinforced, which was according to the similar ratio of 25∶1 and with the degree of compaction K≥94% as the control index. The indoor static load model test was carried out. The variation characteristics of parameters such as embankment internal earth pressure E, the embankment settlement s (including the embankment pavement settlement and the vertical settlement inside the embankment), the ultimate bearing capacity Quk of the embankment, the slope lateral displacement L and the tensile strain ε of the reinforcement were compared and analyzed under the action of uniform load P, with different working conditions such as reinforced and non-reinforced embankment, full-section reinforced and locally reinforced embankment, 3-layer locally reinforced and 4-layer locally reinforced embankment. The results show that: the reinforcement can reduce E and improve the anti-slip performance of the embankment; the effect of full-section reinforced embankment is the best; the internal earth pressure of 3-layer and 4-layer locally reinforced embankment is only 6.15% and 2.17% higher than that of the full-section reinforced embankment; the limited lateral displacement capacity of 3-layer and 4-layer locally reinforced embankment is about 2-4 and 3-4 of that of the full-section reinforced embankment; however, the consumption of reinforcement is 57.14% and 42.86% that of the full-section reinforced embankment. References | Related Articles | Metrics

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Strength Characteristics of Reinforced Soil Considering Indirect Effect LEI Shengyou 2021, 40(08): 114-119.  DOI: 10.3969-j.issn.1674-0696.2021.08.15 Abstract ( )   PDF (705KB) ( )   For the study of the strength of reinforced soil, the direct effect of reinforcement was only considered by most researchers, but the indirect effect of reinforcement should also be considered. If the indirect reinforcement was considered, the strength of reinforced soil would be greatly improved. Thus, from the perspective of indirect reinforcement, the failure of reinforced soil was still divided into tensile failure and adhesive failure. For the triaxial specimen of diagonally reinforced soil under axisymmetric load, the specimen was considered to be in the state of limit equilibrium. By changing the cohesion of the soil in the indirect effect, the sample was considered to be in a static equilibrium state through internal force analysis. Thereby, the expression of the major principal stress of reinforced soil under limit equilibrium condition was obtained. Then the detailed discussion and analysis were made under the situation that the increased cohesive force was covered with reinforced action range, the filler was sand, the angle between the reinforced layer and the sample cross section was zero degree and the indirect action was not considered. The results show that when the cohesive force of the soil increases in the indirect reinforcement action range, the strength of the reinforced soil will be greatly improved; when the effect of indirect reinforcement is the all over the scope of the reinforcement layer, the indirect reinforcement effect will be maximized; when the angle between the reinforcement material and the sample cross-section is zero degree, the reinforcement effect is best; when the indirect reinforcement is considered, the reinforced sand also exhibits a high cohesive force; when the indirect reinforcement effect is not considered, the strength expression becomes the expression of reinforced soil strength under normal conditions. References | Related Articles | Metrics

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Road Performance of SBS Modified Asphalt Mixture Regenerated from Vegetable Oil HOU Yun1, 2, 3, DONG Yuanshuai1, 2, 3, LI Zhihao4, HU Sen4, CAO Xuejuan5 2021, 40(08): 120-125.  DOI: 10.3969-j.issn.1674-0696.2021.08.16 Abstract ( )   PDF (1982KB) ( )   The recycling of old asphalt mixture (RAP) has high economic value and environmental protection benefits. When the content of RAP is high or the aging of old asphalt is serious, it is necessary to add asphalt regeneration agent to ensure the road performance of recycled asphalt. The effects of three kinds of vegetable oil regeneration agents, such as fresh vegetable oil, fried vegetable oil and vegetable diesel oil as well as a traditional mineral oil regeneration agent on the road performance of the aged SBS modified asphalt mixture were studied. Two kinds of the content such as 30% and 50% were selected by RAP, and the optimum content of four kinds of regeneration agents was used to regenerate RAP under the condition of the best ratio of oil to stone, respectively. Finally, the rutting test, trabecular bending test and freeze-thaw splitting test of recycled asphalt mixture were carried out on the recycled asphalt mixture. Based on the proposed experimental conditions, when the content of RAP is 30% and the ratio of oil to stone is 4.8%, the regeneration effect of the aged SBS modified asphalt mixture was the best by using 4.5% fresh vegetable oil as regeneration agent. References | Related Articles | Metrics

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New Tourmaline Composite and Its Asphalt Smoke Adsorption Performance QIAO Zhi1, CHEN Qian2, WANG Chaohui2, NIU Changchang1, GUO Tengteng2 2021, 40(08): 126-131.  DOI: 10.3969-j.issn.1674-0696.2021.08.17 Abstract ( )   PDF (5683KB) ( )   In order to reduce the asphalt smoke emission in the mixing process of traditional hot-mix asphalt mixture and solve the environment pollution problem during the construction of asphalt pavement, the new tourmaline composite was prepared as the modifier based on tourmaline with the function of adsorbing pollutants. The dispersion of the new tourmaline composite in asphalt was studied and the adsorption effect of the new tourmaline composite on asphalt smoke pollutants was analyzed, which provided a reference for the research and application of functional powder materials in asphalt mixture. The research results show that the new tourmaline composite is distributed evenly in asphalt. And the asphalt can completely encapsulate mineral particles, and both of them have good compatibility. At the same condition, the adsorption effect of the new tourmaline composite on asphalt smoke is better than that of tourmaline. Compared with tourmaline, the adsorption effect of the new tourmaline composite is improved by 10.10~19.08%. Compared with the base asphalt, the low-temperature performance of tourmaline and composite modified asphalt is deteriorated, but the temperature sensitivity and high-temperature stability are improved to a certain extent. References | Related Articles | Metrics

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Continuous Visual Reference Facilities Setting at Tunnel Entrance on Expressway PAN Binghong, ZHOU Xizhen, HAN Xueyan 2021, 40(08): 132-139.  DOI: 10.3969-j.issn.1674-0696.2021.08.18 Abstract ( )   PDF (5941KB) ( )   By analyzing the characteristics of the visual reference system of the tunnel entrance, a visual reference column that could establish a strong visual reference system at the tunnel entrance was proposed to ensure the continuity and accuracy of the drives visual reference at the tunnel entrance and improve the driving safety at the tunnel entrance. Based on the statistical analysis of the tunnel cross-section size and the deviation of the driving track caused by the side wall effect when the driver entered the tunnel, combined with the psychological and physiological characteristics of the driver, the recommended length of the transition section of the tunnel entrance pavement width change section was proposed. Moreover, the calculation model of the length and spacing of the visual reference columns inside and outside the tunnel entrance was established. The research results show that the length of the visual reference column setting outside the tunnel entrance should be 200 m, the one inside the tunnel entrance should be 250 m, and the setting interval should be 22 m. References | Related Articles | Metrics

Transportation Equipment

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Intelligent Vehicle Target Detection Algorithm Based on Multi-source Heterogeneous Information Fusion WEI Hanbing, BAI Lin 2021, 40(08): 140-149.  DOI: 10.3969-j.issn.1674-0696.2021.08.19 Abstract ( )   PDF (12786KB) ( )   Aiming at the limitation of single sensor of intelligent vehicle in perceiving environment, an environment perception algorithm based on multi-source heterogeneous information fusion with GPS, binocular depth camera and 16-line LIDAR was proposed, so as to solve the limitation of single sensor in environment perception. Based on GPS time synchronization, the proposed algorithm took the calibrated data of a single sensor as the input of an improved joint calibration algorithm, so as to solve the optimal spatial transformation matrix of multi-source sensors. The SVM segmentation point cloud and European clustering were used to extract the geometric features of the point cloud information, so as to obtain the location information of the obstacles. The space transformation matrix was used to transform the obstacle point cloud information into the image coordinate system, and the 3D point cloud was mapped to the 2D point cloud information. The obstacle position information and category information in images solved by deep learning algorithm were fused to achieve target detection. Through the verification of KITTI dataset and real vehicle test, the accuracy of the proposed algorithm is between 78.13%~85.56% and the average detection time of each frame is 0.16~0.19 s. The proposed algorithm can effectively detect the obstacle both in the light changing and occlusion environment, which has a promising engineering application prospect. References | Related Articles | Metrics

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Occupant Injury Mechanism in Coach Front Collision Based on Seat Dynamic Test GONG Jianqiang1, ZHANG Guozhen2, GAO Yinan3, LIU Jia4, LI Jinjun5, PAN Yuming5 2021, 40(08): 150-158.  DOI: 10.3969-j.issn.1674-0696.2021.08.20 Abstract ( )   PDF (5811KB) ( )   Based on the damage characteristics of occupants in front collision of coach, the front collision test of the whole coach was simulated by designing the dynamic test of occupant seat, and the occupant injury mechanism in front collision of coach was analyzed. The results show that the factors such as seat belt type, energy absorption characteristics of seat filler, seat arrangement and size of restraint partition will have a certain impact on the occupant injury. Compared with the two-point safety belt, the three-point safety belt has a significant effect on improving the risk of occupant injury, with head injury reduced by 66.44%, chest injury reduced by 48.34%, left and right lower limb injury reduced by 45.36% and 65.05% respectively. Seat filler is active and effective in improving the risk of head injury. Compared with ordinary materials, the head damage of the materials with excellent energy absorption properties is reduced by 55.78%. Seat layout with height deviation increases the risk of occupant chest injury, which increases by 11.46%. The risk of head injury of occupant and chest and lower limb injuries of occupant on the side of the aisle can be reduced with the appropriate increase of the size of the restraint partition. References | Related Articles | Metrics

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Structural Design and Simulation Analysis of Multifunctional Bucket of Hydraulic Excavator CAO Yuanwen, GAN Jingsheng, ZENG Bo, YUE Peng 2021, 40(08): 159-164.  DOI: 10.3969-j.issn.1674-0696.2021.08.21 Abstract ( )   PDF (2868KB) ( )   Taking the TX210C hydraulic excavator as the research object, a multi-functional bucket structure design that could carry out front shovel, backhoe and clamping without changing the bucket was proposed. The virtual prototype model was established by Pro-E and ADAMS software, and on this basis, the structure design, kinematics and dynamics simulation analysis of the working device were carried out. Finally, the variation curve of the force at each hinge point and at each hydraulic cylinder were obtained. The results show that the difference between the theoretical size and actual size of the maximum digging radius, maximum digging depth and maximum digging height of the excavator is very small, and the force change is consistent with the actual working conditions, which can realize the conversion between the front and back shovel of the multifunctional bucket and the clamping action of the material. References | Related Articles | Metrics