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08 September 2023, Volume 42 Issue 8 Previous Issue   
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Transportation+Big Data & Artificial Intelligence
Transportation Infrastructure Engineering
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Transportation+Big Data & Artificial Intelligence

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Method of Determining Hydraulic Parameter of Rapids Abating by Non-rated Conditions Full Scale Ship Test XU Guangxiang1，WANG Songning1，WANG Shutao2，CAI Chuang1 2023, 42(8): 1-8.  DOI: 10.3969/j.issn.1674-0696.2023.08.01 Abstract ( )   PDF (880KB) ( )   The hydraulic parameter of rapids abating is a standard for rapids shoal regulation, but it is often difficult to reach the ideal rated condition when it is determined by ship trial. Firstly, three ideal rated conditions of determining hydraulic parameter of rapids abating by ship trial were pointed out and a method of simply determining hydraulic parameter of rapids abating by rated load and rated power conditions was given. Then, according to the balance equations of forces in non-rated conditions and rated conditions respectively, the conversion formulas for converting the measured water speed in non-rated conditions into the speed corresponding to the hydraulic parameter of rapids abating were deduced, and three conversion methods were given, such as Zvankov resistance formula, general resistance formula and modified general resistance formula. According to the results of the still water speed of the class IV waterway of the Lancang River and the real ship test on the beach, the processes of data selection at measarement points, calculation of propulsive coefficient and fitting of slope flow index were demonstrated. The calculation results of three conversion methods were compared, and a simple and reasonable conversion formula was recommended. References | Related Articles | Metrics

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Seismic Performance of Self-centering Bridge Columns with External Energy Dissipators and Restorers WANG Dapeng1,2,LIANG Yinfeng1 2023, 42(8): 9-17.  DOI: 10.3969/j.issn.1674-0696.2023.08.02 Abstract ( )   PDF (4553KB) ( )   In order to develop rocking self-centering (RSC) bridge columns, which was easy to realize damage control, the buckling restrained brace (BRB) was selected as the exterior energy dissipator and the spring was used as the exterior self-centering device, and BS-RSC piers were designed. Firstly, Opensees finite element software was used to establish a numerical analysis model for BS-RSC bridge piers and the correctness of the proposed model was verified. Then, the effects of BRB yield strength, spring stiffness and axial compression ratio on the hysteresis performance of BS-RSC bridge piers were analyzed, and dynamic time-history analysis was also carried out. Finally, the influence of different parameters on the maximum displacement angle on pier top and residual displacement angle was studied. The research results show that the hysteretic curve of BS-RSC pier is full. BRB can significantly improve the energy dissipation capacity of BS-RSC piers, and control spring stiffness can control the residual displacement without affecting the overall energy dissipation. Under dynamic time-history analysis, it is found that under rare earthquakes, the pier residual displacement angle is at a low value, and the maximum displacement angle on pier top decreases significantly with the increase of BRB yield strength, which indicates that the BS-RSC bridge pier is a new type of bridge pier with coordinated work of various components, clear functions, and excellent energy dissipation capacity and self-centering capacity. References | Related Articles | Metrics

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Design Method of Concrete-Filled Steel Tubular Arch Bridges Arch Rib Height Based on Cosine Curve Change ZHOU Shuixing1， BAI Xingrong2，WANG Peng2，DENG Yekui3 2023, 42(8): 18-22.  DOI: 10.3969/j.issn.1674-0696.2023.08.03 Abstract ( )   PDF (823KB) ( )   The section form of equal width and variable height is mostly adopted in long-span concrete-filled steel tubular arch bridges. Based on the analysis of the design parameters affecting the variable section height in the Ritter formula, a new method for the variable section height design of steel tubular arch was proposed, that is, the section height of arch rib was defined as the ratio of the power of the arch crown height to the cosine of the horizontal inclination of the arch axis, and the power was uniquely determined by the equations of the arch crown height, arch foot height and arch axis. Combined with the ratio of rise to span and arch axis coefficient commonly used in concrete-filled steel tubular arch bridges, the range of power value was given. In order to verify the feasibility of the proposed method in the design of long-span steel tubular arch, the dynamic characteristics and elastic stability analysis of two concrete-filled steel tube arch bridges were carried out. The results show that, compared with the calculation results of design documents and Ritter formula, the concrete-filled steel tubular variable section arch designed by the proposed method has a difference in chord axial force between 1.7% and 7.0%. The difference in dynamic characteristics, elastic stability, and web stress is within 5%. The proposed design method can provide reference for the design of concrete-filled steel tubular arch bridge in the future. References | Related Articles | Metrics

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Effect of Mixed Sand on the Mechanical Properties and Pore Structure of Concrete HUANG Weirong1, YAN Maohao2, TONG Zan3, HE Yuexiao1, WANG Jiao2, CHEN Hang2 2023, 42(8): 23-29.  DOI: 10.3969/j.issn.1674-0696.2023.08.04 Abstract ( )   PDF (1479KB) ( )   The influence rule of pore structure of three kinds of fine aggregate concrete on the mechanical properties was studied by low field nuclear magnetic resonance instrument, and the micro morphology of the three kinds of concrete was observed by scanning electron microscope. The research results show that the mixed sand concrete meeting the requirements of mechanical properties can be prepared by replacing part of natural sand with machine-made sand. Under the condition of constant water binder ratio, the mechanical property index of concrete with 50% replacement rate of machine-made sand is the best. The total porosity of mixed sand concrete is 3.4%, the proportion of micropore (r≤0.1 μm), small hole (0.1 μm＜r≤1 μm), large hole (1 μm＜r≤1 000 μm) is all smaller than that of natural sand concrete and machine-made sand concrete, and the uniformity of pore size distribution is also better than that of natural sand concrete and machine-made sand concrete. The hydration products of cement slurry and appropriate amount of stone powder in mixed sand concrete make the interface transition zone more compact, which can improve the internal structure and enhance the mechanical properties. References | Related Articles | Metrics

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High and Low Temperature Performance of PPA/SBR Modified Asphalt Mastic and Mixture under UV Aging XU Yanling, ZHU Hongzhou, QING Liang, YIN Chunxin 2023, 42(8): 30-37.  DOI: 10.3969/j.issn.1674-0696.2023.08.05 Abstract ( )   PDF (4380KB) ( )   The high and low temperature rheological properties of 90# matrix asphalt mastic, SBR modified asphalt mastic and PPA/SBR modified asphalt mastic with powder to binder ratios of 0.6, 0.9 and 1.2 before and after UV aging was studied by high temperature scanning test and BBR low temperature creep test. The high and low temperature performance of asphalt mixture before and after UV aging was analyzed by use of high-temperature rutting test and low-temperature small beam bending test. Meanwhile, the rutting factor aging index ASTA, creep stiffness aging index SAI, creep rate aging index mAI, dynamic stability aging index DAI and bending stiffness modulus aging index SBAI were also introduced to quantitatively analyze the anti-ultraviolet aging of asphalt mastic and asphalt mixture. The results show that the high-temperature deformation resistance of asphalt mortar is improved after UV aging, but the low-temperature crack resistance of asphalt mortar is significantly reduced after UV aging. For asphalt mixture, the high-temperature rutting resistance of 90# matrix asphalt mixture and SBR modified asphalt mixture is deteriorated by UV aging, the rutting resistance of PPA/SBR modified asphalt mixture is improved, while the low-temperature crack resistance decreases obviously after UV aging. However, PPA/SBR modified asphalt mixture exhibits the best low-temperature crack resistance both before and after UV aging. It is indicated that addition of PPA can effectively improve the high-temperature deformation resistance, low-temperature cracking resistance, and UV aging resistance of SBR modified asphalt mortar and asphalt mixture. The research results show that PPA/SBR asphalt material is very suitable for extremely cold and high-altitude areas. References | Related Articles | Metrics

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Relationship between Sound Absorption Performance and Pore Structure of Porous Asphalt Mixture Based on Sound Transmission Simulation CHEN Jun1 ， SUN Zhenhao 1， LI Jiahao 1,2， WANG Junpeng 1 2023, 42(8): 38-44.  DOI: 10.3969/j.issn.1674-0696.2023.08.06 Abstract ( )   PDF (1163KB) ( )   To investigate the effect of pores in porous asphalt mixtures on noise absorption, the three-dimensional (3D) connected pores of OGFC-13 with different porosity were reconstructed and separated by use of XCT scanning porous asphalt mixture specimens. The shape characteristics of connected pores, such as curvature, length, inner wall roughness, cross-sectional area, and ellipticity were analyzed. The finite element software was used to simulate the sound transmission in a standing wave tube, and the sound absorption coefficients of porous asphalt mixtures under different sound frequencies were obtained. The relationship between the pore shape characteristics of the mixture and the sound absorption coefficients at high, medium, and low frequencies was analyzed. The results show that although the curvature of the connected pores in OGFC-13 ranges from 0.25 to 0.35 mm-1, the three-dimensional connected pores are extremely abundant, with a length of connected pore over 980 mm in a 3 cm cube. The ellipticity of nearly 30% of the pore cross-section is around 0.9, and the roughness of the inner wall of the connected pores is extremely uneven, showing a clear bimodal distribution. There is a certain linear relationship between the cross-sectional size of the pores, the roughness of the inner wall, and the sound absorption coefficient in the high-frequency range (2000~3000 Hz). The larger the pore size, the rougher the inner wall, and the stronger the sound absorption ability of the mixture to high-frequency sound waves. References | Related Articles | Metrics

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Key Technology of Production and Construction of Domestic High-Temperature Cured Epoxy Asphalt Mixture LIU Pan1, 2, LIU Yang1, LI Kai1, QUAN Hongbin2 2023, 42(8): 45-50.  DOI: 10.3969/j.issn.1674-0696.2023.08.07 Abstract ( )   PDF (1091KB) ( )   According to the performance characteristics of epoxy asphalt material, the construction operation time of domestic high-temperature cured epoxy asphalt mixture at different temperatures was studied. The influence of mixing process and production construction temperature on mixture Marshall indicator was investigated, and the influence rule of curing conditions on the formation of mixture strength was studied. The test results show that the domestic high-temperature cured epoxy asphalt mixture has a longer construction operation time (3~4h) in the range of 160~180 ℃, which can meet the needs of engineering application. Mixing process has little effect on mixture performance, in which the main agent and curing agent are usually mixed evenly, and then mixed with the base asphalt and stone materials. The production construction temperature has a significant impact on mixture performance. The mixing temperature should be between 160~180 ℃, the rolling temperature should not be lower than 130 ℃, and the construction environment temperature should not be lower than 10 ℃. The development of mixture strength mainly depends on curing time and curing temperature. Accurately grasping the key nodes of high-temperature cured epoxy asphalt mixture in production and construction process could effectively ensure the smooth implementation of project. References | Related Articles | Metrics

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Effect of Reaction Solution Amount on Microbial Reinforcement of Silt in Multi-Treatments ZHAO Zhifeng, WANG Haoran 2023, 42(8): 51-56.  DOI: 10.3969/j.issn.1674-0696.2023.08.08 Abstract ( )   PDF (5327KB) ( )   The silt can be strengthened effectively by the bio-cementation approach, in which the Sporosarcina pasteurii solution was premixed with dry soil followed by cementation solution (including equal ratio of calcium chloride and urea) percolation several times. The amount of reaction solution used (the number of percolation treatments of cementation solution and the volume of bacterial solution) has a significant impact on the reinforcement effect. The test results of cementation solution percolation treatments show that the samples reinforced with different percolation treatments have good stability in water. As the number of infiltration treatments increases, the CaCO3 content and unconfined compressive strength in the sample gradually increase, and the increase in the late percolation stage is higher than that in the early stage. The scanning electron microscope photos indicate that the crystal size of CaCO3 is much bigger when there are more times of cementation solution percolation. The test results of bacteria solution volume show that when the amount of bacterial solution is 1.0 time of the pore volume (1.0Vv), relatively more CaCO3 is generated in the sample, and the unconfined compressive strength is also higher. Reducing the volume of bacterial solution could not improve the reinforcement effect. Besides, when the percolation times is less, the reinforcement of samples treated with 0.6Vv of bacteria solution is poor. References | Related Articles | Metrics

Transportation Infrastructure Engineering

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Stability Analysis of Unsaturated Soil Slope Considering Seepage-Stress Coupling under Different Rainfall Conditions ZHOU Yiliang， HE Qi， LI Ming， SUN Zhiyuan， HE Fenghan 2023, 42(8): 57-63.  DOI: 10.3969/j.issn.1674-0696.2023.08.09 Abstract ( )   PDF (3164KB) ( )   Rainfall is one of the main factors that induce slope instability and damage, and the resulting economic losses are extremely huge. The effective stress and pore water pressure of unsaturated soil slope was compared and analyzed by the finite element numerical analysis software Geo-studio, with and without considering the coupling effect of seepage and stress. The effects of different rainfall intensities, durations and types on slope stability were studied. The results show that the coupling effect of seepage and stress accelerates the rise of surface pore water pressure and the dissipation of soil matrix suction and reduces the strength of soil. The safety coefficient obtained by the coupled analysis is smaller than that obtained by the uncoupled analysis. The greater the rainfall intensity is, the faster the rainwater infiltration speed is, and the faster the slope stability safety coefficient decreases. Moreover, the longer the rainfall duration is, the deeper the influence of rainfall infiltration is, and the lower the slope stability safety coefficient is. Under the action of frontal rainfall, the safety coefficient of slope stability decreases most rapidly, followed by the uniform rainfall, and finally rear frontal rainfall. References | Related Articles | Metrics

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Prevention and Cure Countermeasures on Groundwater Table Rising Disaster in the Qaidam Basin DANG Xueya1,2,3, GU Xiaofan1,2,3, CHANG Liang1,2,3 2023, 42(8): 64-69.  DOI: 10.3969/j.issn.1674-0696.2023.08.10 Abstract ( )   PDF (1223KB) ( )   The control factors of groundwater table rising disaster in Golmud and Delingha were analyzed from the groundwater recharge, runoff and discharge. The research results show that: in disaster years, the river runoff significantly increases, the precipitation in plain areas increases somewhat, and there is no significant change in the irrigation water consumption of farmland; meanwhile, the groundwater runoff and discharge conditions remain basically unchanged. Therefore, it is inferred that the significant increase of river runoff is the dominating factor to form groundwater table rising disaster. Further analysis and research reveal that the root cause of the disaster is the drastic increase in precipitation in the source area of the river caused by climate change on the Qinghai-Tibet Plateau. Based on the concept turning harm into a benefit, combined with the local water resources demand, the water storage conditions of the Quaternary loose aquifer system in the piedmont plain area and the existing water conservancy facilities, the countermeasures and specific implementation measures are proposed by establishing a trinitarian water source regulation system that integrates canal system diversion, underground reservoir regulation and storage and water source interception and exploitation, in order to completely eliminate the disaster of groundwater table rising. References | Related Articles | Metrics

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Reliability Design of Braking Slope Bed Length of Highway Escape Ramps ZHANG Hang1, LIU Yang1, LYU Nengchao2 2023, 42(8): 70-76.  DOI: 10.3969/j.issn.1674-0696.2023.08.11 Abstract ( )   PDF (570KB) ( )   In order to ensure that the brake failure vehicle can safely slow down and stop after entering braking slope bed in the design of highway escape ramps, the reliability theory was introduced, and the braking slope bed length calculation model of the escape ramps was established under the limit state condition. Then, the reliability function of the braking slope bed length was established based on the proposed model. The related parameters such as the entry speed, rolling resistance coefficient and the braking slope bed gradient were counted and their distribution rule was also analyzed. The Monte Carlo method was used to calculate the reliable probability of the braking slope bed length of the highway escape ramps with the main line design speed of 120, 100 and 80 km/h, respectively. According to the requirement of 95% reliability probability of highway pavement structure, the reliability design of the braking slope bed length of the highway escape ramps was carried out, and the recommended values of the braking slope bed length corresponding to different main line design speeds were given. The results show that: the design value of the brake ramp bed length of the refuge lane changes with the design driving speed, and the reliability probability corresponding to the mainline design speed of 120, 100 and 80 km/h is 39.55%, 46.68% and 54.03% respectively, with insufficient safety and reliability. The recommended safety values for the braking slope bed length corresponding to the main line design speeds of 120, 100, and 80 km/h are calculated based on the corresponding minimum safe design entry speeds of 126, 123, and 122 km/h, as well as the longitudinal slope and slope bed materials selected in the design. References | Related Articles | Metrics

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Construction and Verification of Superhighway Virtual Track Model HE Yongming1,2, FENG Jia1, QUAN Cong1,2,CAO Jian1,3,CHEN Shisheng1,2 2023, 42(8): 77-85.  DOI: 10.3969/j.issn.1674-0696.2023.08.12 Abstract ( )   PDF (2131KB) ( )   In order to improve the driving safety of superhighways, the virtual track system of superhighways was studied by establishing mathematical models. The proposed system consisted of an information acquisition subsystem, an information processing subsystem and an information feedback subsystem. Through theoretical analysis and the data obtained by information acquisition subsystem, the virtual track deviation calculation models on straight and curved sections were established. The early warning signal values of vehicles deviating from the safety range of virtual track were obtained by using the calculation model. The estimated time and distance data required for vehicles to leave the virtual track safety range on the curved road sections were also obtained. The research results show that when the vehicle is driving on the straight section of superhighway, the absolute value of the square difference between the theoretical distance and the sensor detection distance is less than 1.85, 2.78 and 3.70 m2, the deviation distance of the vehicle from the centerline can be guaranteed to be less than 0.50, 0.75 and 1.00 m, respectively; when the vehicle is driving on the curved road section, the time required for the vehicle to leave the virtual track safety range is related to the driving speed, the virtual track safety range and the curve radius. When the threshold values of deviation from virtual track are 0.50 m, 0.75 m and 1.00 m respectively, as well as the early warning signal value is 2 m, 3 m and 4 m, it can be ensured that the vehicle does not exceed the virtual track safety threshold. Therefore, the virtual track system of the superhighway can limit the vehicles to travel within the safe range of the virtual track, ensuring the safety of the vehicle driving on the superhighway. References | Related Articles | Metrics

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Vulnerability Analysis of Highway Network in Shaanxi Province Based on Complex Network LI Bo1, LI Zhizheng2, LIU Huitian1 2023, 42(8): 86-95.  DOI: 10.3969/j.issn.1674-0696.2023.08.13 Abstract ( )   PDF (4337KB) ( )   In order to improve the survivability of the highway network in Shaanxi Province in response to emergencies and ensure the safe operation of the highway network, the vulnerability of the highway network was studied by using the complex network theory. Firstly, the weighted network model of highway in Shaanxi Province was established by the original mapping method, and the topological structure characteristics of highway network were analyzed from the aspects of nodes and edges. Secondly, an improved attack strategy was designed from the perspective of the maximum connected subgraph, and the vulnerability of highway network was analyzed from node attack and edge attack. The results show that: in terms of vulnerability of highway network, whether it is node attack or edge attack, highway network shows certain vulnerability to betweenness-based attack strategies; especially in the two attack strategies of improved betweenness attack and recalculation betweenness attack, highway network shows stronger vulnerability. In terms of attack effect, the improved degree attack strategy is better than the recalculated degree attack strategy and the initial degree attack strategy; the improved betweenness attack strategy is slightly better than the recalculation betweenness attack strategy and significantly better than the initial betweenness attack strategy. It is indicated that the improved attack strategy can not only effectively destroy the maximum connected subgraph, but also take into account the impact on network efficiency, which also verifies the effectiveness of the improved attack strategy. References | Related Articles | Metrics

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Behavioral Intention to Use Tourism Mobility Service Incorporating Traveler Psychological Needs LI Wanying1,2, GUAN Hongzhi2,HAN Yan2 2023, 42(8): 96-105.  DOI: 10.3969/j.issn.1674-0696.2023.08.14 Abstract ( )   PDF (2259KB) ( )   To discuss travelers behavioral intention to use tourism mobility service under mobility-as-a-service (MaaS) environment, a service acceptance model (SAM) considering psychological needs was proposed. The subjective evaluation data of influencing factors on MaaS were collected by an online questionnaire survey, and the internal consistency, reliability, convergence validity and discriminant validity as well as the assumptions of SAM were tested by structural equation model. The results indicate that the perceived usefulness has the greatest positive impact on travelers intention to use MaaS, followed by the perceived ease of use, while the perceived risk has a significant negative effect. The perceived usefulness and perceived ease of use affect the consistency of travelers habitual patterns, thereby indirectly affecting their intention to use them. The satisfaction of travelers psychological needs plays an important role in their behavioral intention to use MaaS. The psychological needs of travelers, such as autonomy, ability, relevance, and altruism, affect the perceived usefulness, the perceived ease of use and the perceived risk, thereby indirectly affecting travelers intention to use MaaS. SAM can effectively describe the intention to use tourism mobility service and provide support for developing refined and differentiated strategies for heterogeneous travelers. References | Related Articles | Metrics

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Driving Style Identification and Transfer Characteristics of Steady Car-Following States PENG Jinshuan, ZHAO Wenchao, LIU Lu, LIU Tong, ZHANG Lei 2023, 42(8): 106-113.  DOI: 10.3969/j.issn.1674-0696.2023.08.15 Abstract ( )   PDF (4155KB) ( )   To explore the characteristics and driving style identification method of different kinds of drivers in steady car-following situations, twenty drivers were recruited to carry out real-vehicle driving tests. The indicators such as self-driving speed, following distance, and following time interval under natural driving conditions were collected, and the extraction rules of steady car-following events were determined based on radar data, etc. The distribution pattern and following characteristics of driving behavior indicators under stable following conditions were analyzed by coupling analysis. The following distance, following time interval together with opening degree of accelerator pedal were selected as clustering indicators, and K-means clustering algorithm was used to perform clustering analysis on stable following events in section 301. According to the frequency and proportion of different style types, drivers were divided into three types of styles (conservative, general, and radical). Finally, the clustering results were verified by the CART decision tree method, and the transfer characteristics of driving style under long-term steady car-following states were furtherly analyzed. The research results show that the following distance and the opening degree of accelerator pedal tend to increase as the self-driving speed increases, and have significant differences among different speed ranges. There is no significant change in the mean value of car-following time interval with different speed ranges, and it is stably distributed between 2.57~2.72 s. The CART decision tree verifies that the overall coincidence rate of driving style clustering results is 99.7%. There are significant differences in speed, opening degree of accelerator pedal, the following distance and following time interval for drivers with different types. Over time, conservative drivers tend to be more conservative, aggressive drivers tend to be more aggressive, and average drivers are relatively stable. The research results can provide technical support for the formulation of car-following control strategies and parameters of high-level automatic driving systems. References | Related Articles | Metrics

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Fire Risk Management of Extra-long Road Tunnel Based on GIS LIU Hongyong1， XU Min1，ZHANG Jingxiao2，XU He3 2023, 42(8): 114-124.  DOI: 10.3969/j.issn.1674-0696.2023.08.16 Abstract ( )   PDF (1916KB) ( )   In order to effectively reduce the risk of fire in tunnels, a relatively complete fire risk assessment system for highway tunnels was constructed, so as to achieve more scientific management of fire risks. GIS technology was innovatively employed in the fire risk management. Firstly, the advantages of GIS application in tunnel fire risk management were analyzed, the tunnel fire risk management method based on GIS was analyzed in detail, and the tunnel fire risk evaluation and classification were realized by incorporating ArcGIS. Secondly, the tunnel risk management system based on GIS technology was constructed and the operation of the application end was explained. Finally, the risk assessment model was established for tunnel fires, including four primary indicators of hazard, vulnerability, exposure, and disaster prevention and mitigation capabilities, as well as 33 secondary indicators. Entropy weight method and improved fuzzy comprehensive evaluation method were used to carry out the fire risk assessment of Xishan Tunnel and Yangquan Beiru Tunnel, and the electronic map was displayed. The research shows that the GIS-based fire risk assessment model can effectively accomplish the functions such as the hazard analysis, exposure analysis, vulnerability analysis and disaster prevention and mitigation capability analysis. Moreover, the feasibility of the proposed system is verified by the case study, which provides safe and reliable information and intelligent decision-making support for comprehensive fire risk management and emergency response of extra-long tunnels. References | Related Articles | Metrics

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Prediction Method of Aircraft Fuel Consumption Based on Convolutional Neural Network ZHAO Yuandi, WANG Zhongyi 2023, 42(8): 125-131.  DOI: 10.3969/j.issn.1674-0696.2023.08.17 Abstract ( )   PDF (969KB) ( )   Aiming at the development goal of green civil aviation, it is of great significance to accurately calculate aircraft fuel consumption. The problem of aircraft fuel consumption was studied and analyzed. Based on Tensorflow deep learning framework, the prediction model of aircraft fuel consumption was established by using convolutional neural network. The prediction results were compared with the existing flight plan and multi-layer perceptron neural network models to verify the accuracy of the convolution neural network model, and the 10-fold cross validation was carried out to verify the robustness of the proposed model. The results show that the average error rate of the prediction results of the convolution neural network model is 5.26%, which is significantly better than 17.67% of the existing flight plan and 7.69% of the multi-layer perceptron model. The error rate variance of 10-fold cross validation of the proposed model is 0.16%. Therefore, the aircraft fuel consumption prediction model based on convolutional neural network has good accuracy and robustness, which can provide airlines with more accurate fuel weight carried by aircraft, avoid more fuel consumption, effectively reduce operating costs and achieve the energy-saving goal of green civil aviation. References | Related Articles | Metrics

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Port Throughput Prediction Based on FGM-SVR Combined Model DENG Ping1，LIU Shulong2 2023, 42(8): 132-138.  DOI: 10.3969/j.issn.1674-0696.2023.08.18 Abstract ( )   PDF (757KB) ( )   In order to improve the prediction accuracy of port throughput, a combined prediction model based on fractional order cumulative forecast GM (1,1) prediction model FGM (1,1) and support vector regression (SVR) was established to predict the port throughput. Firstly, FGM (1,1) model and SVR model were applied to predict the port throughput respectively. Then, aiming at the problem that the traditional combined model weighting could not take into account the predictive power of each individual model at each time point, a weighting method based on of induced ordered weighted averaging (IOWA) operator was proposed for combination prediction. Finally, taking the cargo throughput of Chongqing Port from 2005 to 2020 as the data sample for example verification, the FGM (1,1) model, SVR model and weighted combined model were used for port throughput prediction, respectively. The prediction accuracy of the three models were compared and these three models were used to respectively predict port throughput from 2021 to 2024. The research results show that the root mean square error, mean absolute error and mean absolute percentage error of the combined model based on IOWA are significantly smaller than those of each single prediction model．The proposed combined model could provide a new method for port throughput prediction. References | Related Articles | Metrics

Transportation Equipment

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Multi-axis Active Steering Control Strategy of Semi-Trailer Trains DENG Zhaowen1,3, KONG Xinxin2, GAO wei2,3 2023, 42(8): 139-146.  DOI: 10.3969/j.issn.1674-0696.2023.08.19 Abstract ( )   PDF (2210KB) ( )   To address the problem of poor low-speed maneuverability and high-speed stability of semi-trailer trains, a three-degree-of-freedom linear reference model of three-axis semi-trailer car train was established. Taking the yaw rate of tractor and trailer approaching to the reference value and the sideslip angle of the center of mass approaching to zero as the design goal, a linear quadratic form regulator (LQR) was used to formulate the active steering control strategy for tractor and trailer. The simulation software was applied to simulate the LQR active steering control of vehicle under low-speed 360° roundabout and high-speed single lane-change maneuver, and it was compared with the uncontrolled vehicle model. The simulation results show that the low-speed maneuverability and high-speed stability of the LQR active steering control vehicle are effectively improved, which proves that the proposed control strategy has good control effect. References | Related Articles | Metrics

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Multi-objective Optimization of Hub Bearing Life Based on Parameter Sensitivity Analysis ZHU Sunke1，SUN Yonggang2，DONG Shaojiang1,3，JIANG Yuan4 2023, 42(8): 147-154.  DOI: 10.3969/j.issn.1674-0696.2023.08.20 Abstract ( )   PDF (4180KB) ( )   In order to improve the loading fatigue life of a certain type of third-generation hub bearing, with rated dynamic load and rated static load as the response indexes, the sensitivity analysis of the structural parameters of hub bearing was carried out by orthogonal experimental design. The main influencing factors such as the number of rollers, the diameter of rollers, the diameter of pitch circle and the curvature radius of inner and outer grooves of the hub bearing were taken as design variables, and the multi-objective optimization mathematical model of the fatigue life of the hub bearing was established. The non-dominated sorting genetic algorithm (NSGA-II), multi-island genetic algorithm (MIGA) and optimization particle swarm optimization algorithm (MOPSO) were used to optimize the solution, and the optimal structural design parameters of hub bearing were obtained. The finite element simulation analysis method was used to compare and verify the fatigue life of the spinning and riveting assembly forming hub bearing before and after the optimization. The results show that the above optimization strategy has achieved the improvement of the overall performance of the hub bearing dominated by two objective functions, improved the stress concentration of each component of the hub bearing, and increased the fatigue life of the hub bearing. After optimization, the maximum stress of the structure is reduced by about 5.1% compared with that of the initial design and the life is increased by about 3.8% compared with that of the initial design structure, which indicates that the multi-objective optimization design of the fatigue life of the hub bearing is effective. References | Related Articles | Metrics