交通运输工程学报

Cover and Contents of Vol.25, No.3, 2025

Cover Contents

Overview on effect of wheel diameter difference on service performance for railway vehicles

WANG Kai-yun, SUI Shun-qi, XIE Bo, LING Liang, CHEN Shi-qian, ZENG Dong-liang, LI Yan-lei

Abstract: The research progress of wheel diameter difference (WDD) in railway vehicles was reviewed from five aspects: vehicle dynamics performance, wheel-rail contact, wheel wear and rolling contact fatigue, service status of other components, and the WDD identification. The variation laws of vehicle motion stability, wheel-rail contact status, and tread damage under the condition of WDD were discussed. The current research status and development trend of the influence of WDD on the service performance of railway vehicles were summarized. The current situation and deficiencies of WDD identification in railway vehicles were analyzed. The results show that with the increase in the WDD, the critical speed of the vehicle can be reduced, and the dynamics performance of the vehicle will deteriorate; the shape and stress distribution of the contact spots for the two wheels on both sides can be changed. The normal contact stress of the contact spot for the smaller wheel can be increased, and the opposite condition can be observed on the larger wheel; the tread wear rate can be increased, and the tread rolling contact fatigue may even be induced. In addition, some other problems, such as the unbalanced load on the traction motor, motor temperature rise, and phase difference of the bearing areas between the axle-box bearings on both sides of a wheelset can be induced by the WDD, which will affect the service status and lifespan of other components. Future studies should be focused on systematically conducting theoretical and experimental studies about the WDD to ascertain its formation mechanism. The control measures for WWD from multiple dimensions such as vehicle service status, maneuver conditions, and external service environment can be proposed. In response to the development of a maintenance system for railway vehicles shifting from planned maintenance to condition-based maintenance, research on intelligent detection and recognition of WWD based on data-driven and hybrid data-model driven methods should be carried out to provide theoretical guidance for the transformation of vehicle maintenance system, cost reduction, and efficiency improvement.More>

2025, 25(3): 1-11. doi: 10.19818/j.cnki.1671-1637.2025.03.001

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Review of cause diagnosis of transverse cracks in semi-rigid base asphalt pavement

ZHU Jun-qing, YIN Yi-qun, MA Tao, TONG Zheng, HUANG Si-qi

Abstract: The advancements and existing issues in the cause diagnosis method of transverse cracks in semi-rigid base asphalt pavement were reviewed and summarized. Regarding evaluation methods, current techniques for transverse crack assessment and their development status were comprehensively analyzed, and a classification method based on failure cause mechanisms was proposed to provide theoretical foundations for cause diagnosis. In terms of classification approaches, the formation mechanisms and influencing factors of transverse cracks were reviewed, and a database of transverse crack causes was established. In terms of diagnostic methods, critical limitations in existing practices were identified, and a stepwise diagnostic framework for transverse crack causes was proposed. Research results indicate that existing evaluation methods lack correlation with crack causes, while the proposed classification method based on cause and development trends can provide a basis for diagnosis. The established crack cause database incorporates multiple mechanisms involving material properties, structural design, construction practices, and loading/environmental impacts, serving as a reference for cause analysis. The developed diagnostic framework integrates four operational dimensions: baseline pavement investigation, special factor exclusion, comprehensive load-environment analysis, and targeted area testing for refined diagnosis, offering practical guidance for engineering practices. Field validation demonstrates that base layer cracking is the primary cause of cracking in the verified sections, which, under heavy traffic and overload conditions, leads to reflective cracks propagating upward to the surface, with bottom-up reflective cracking being the main type. The proposed transverse crack cause database and diagnostic framework provide both theoretical foundations and practical references for developing effective crack treatment strategies in asphalt pavement engineering.More>

2025, 25(3): 12-32. doi: 10.19818/j.cnki.1671-1637.2025.03.002

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Applications and challenges of digital twin in intelligent construction of transportation infrastructure

LUO Dan, HUANG Xiao-qin, LENG Fei-xian, ZHANG Yan, LIU Wei, HUANG Xing

Abstract: To comprehensively understand the current application of digital twin in the intelligent construction of transportation infrastructure, the definition and reference frameworks of digital twin were elucidated. The emerging data acquisition methods and transmission technologies were summarized. The application value and representative cases of digital twin in the intelligent construction of transportation infrastructure were analyzed, and the key challenges encountered during implementation were discussed. Analysis results show that, by establishing virtual environments capable of multi-source data integration and real-time interaction, the digital twin significantly enhances collaborative management and intelligent decision-making capabilities in the intelligent construction of transportation infrastructure. Its interactive feedback and self-evolving features facilitate human-machine collaboration, resource optimization, construction safety, and intelligent operation and maintenance. Nevertheless, the current digital twin remains in its early developmental stage in the field of infrastructure. Issues exist including immature core technologies, fragmented system integration, and non-uniform standards. Therefore, sustained optimization is needed to achieve efficient deployment and stable operation. The overall reference architecture of digital twin promotes resource integration and multi-modal compatibility, thereby supporting inter-organizational coordination. However, few existing frameworks offer service functionalities. Furthermore, the lack of complete standards and unified evaluation systems constrains the wide application and cross-sector adaptability of the technology. The novel sensing technologies have markedly improved data acquisition in accuracy and timeliness, though with a high initial cost. In terms of data quality, the absence of strategic data analysis tends to result in data redundancy. In addition, multi-source data integration poses significant risks in security assessment and privacy protection. Future construction of digital twin should focus on overall planning at the system level. Data standardization should be advanced, and interoperability enhanced. Data management and safety mechanisms should also be optimized to ensure the reliability and extensibility of the technology system. Moreover, technological advancement and industrialization should be accelerated by collaborative innovation among academia, research institutions, and industry, along with cross-disciplinary platform construction and policy guidance.More>

2025, 25(3): 33-64. doi: 10.19818/j.cnki.1671-1637.2025.03.003

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Full-scale model static tests of integral joint on the Shiziyang Bridge

CHEN Wei-le, LIU Zhen-bei, LIU Shuang, LIU Yong-jian, CUI Gao-yan, WANG Kun, MA Wen-jie, JIANG Lei

Abstract: In order to study the out-of-plane rotational behavior of the integral joint of the plate-truss composite steel truss stiffening girder and evaluate the structural safety of the integral joint of the Shiziyang Bridge under the design load, a full-scale model static load test of the integral joint was carried out. The finite element model of Shiziyang Bridge was established to determine the magnitude of the test load, and the finite element model of the stiffening girder segment and joint was used to determine the strain and deformation measurement points. The sectional normal stresses of the crossbeam, web members, and chord of the joint under out-of-plane loading were measured. Based on the stress analysis theory of thin-walled structures, the bending normal stresses of the crossbeam and web members were extracted. The out-of-plane bending moments were calculated, and the accuracy of this method was verified. The out-of-plane rotational deformation of the joint was tested. The out-of-plane moment rotation curve of the joint was plotted, and the out-of-plane rotational stiffness of the joint was obtained. The restrained torsional normal stress of the chord was extracted using the measured sectional normal stress, and the torsional performance of the chord was evaluated. The three-dimensional stress of the local areas of the joint was tested, and the Mises stresses at each measurement point were calculated to evaluate the safety of the joint under out-of-plane static load. Test results show that the joint remains in the elastic stage under the design load. The out-of-plane bending moment calculated by this method based on sectional normal stress analysis agrees well with the theoretical value, with a relative error ranging from 2.5% to 10.0%. Under out-of-plane load, obvious shear lag effects are observed in the crossbeam and web member sections, with a 40% reduction in the effective width of the top flange of the crossbeam and a 10% reduction in the effective width of the flanges of web members. The out-of-plane rotational stiffness of the integral joint of Shiziyang Bridge is between that of a rigid joint and a hinged joint and is significantly influenced by boundary conditions. The maximum restrained torsional normal stress of the chord is 4.19% of the axial stress under design live load. The most unfavorable stress position under out-of-plane load is at the welding hole of the chord diaphragm where the Mises stress is lower than the design strength of steel, with a safety factor of 2.32. The test results and the proposed calculation method can serve as a reference for the study of the out-of-plane mechanical behavior of steel truss girder joints.More>

2025, 25(3): 65-81. doi: 10.19818/j.cnki.1671-1637.2025.03.004

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Seismic response and numerical simulation of concrete-filled steel tubular composite column with UHPC plates

WEI Jian-gang, YING Hao-dong, YANG Yan

Abstract: To study the seismic response characteristics of concrete-filled steel tubular composite columns with UHPC plates, two 1∶8 scaled specimens were designed and fabricated. The pseudo-dynamic test was performed with ground motion characteristics, ground motion intensity, axial compression ratio, and plate material as parameters. A full-scale model was then established based on OpenSees software to conduct numerical simulations. A calculation method was ultimately proposed for the response displacement of full-scale structures under E1 and E2 seismic loads. Research results show that ground motion characteristics significantly affect the seismic response of specimens. Under different ground motions with the same minor earthquake intensity, the maximum response displacement of specimens S1 and S2 are 4.16 and 4.89 times the minimum one, respectively. With the increasing intensity of ground motions, the specimens go through elastic, elastoplastic, and plastic damage stages. The two specimens share a similar failure pattern. Both have the overall compression bending type damage, manifested as the bottom of the UHPC plate cracking, the steel plate local buckling deformation, the bottom of the column limb steel tube to form a buckling ring, or the occurrence of the full-section tear. The axial compression ratio slightly affects the initial lateral stiffness of the specimen. However, the larger axial compression ratio brings the higher initial stress of the specimen. The earlier yielding and buckling deformation of the column limb steel tube leads to a more violent final failure pattern. Under ground motion of equal intensity, the initial lateral stiffness of a concrete-filled steel tubular composite column with UHPC plate is approximately 13.7% higher than that of the concrete-filled steel tubular composite column with ordinary reinforced concrete plate. Stiffness degradation is delayed to a certain extent, and cumulative hysteretic dissipation is increased by approximately 41.2%. According to the numerical simulation analysis results of the full-scale model, the slenderness ratio is a key factor for the seismic response and the amplification coefficient of the specimens. The proposed calculation method for the response displacement of full-scale specimens under E1 and E2 seismic loads has good accuracy.More>

2025, 25(3): 82-100. doi: 10.19818/j.cnki.1671-1637.2025.03.005

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Vortex-induced vibration test of twin-box girder with inverted L-shaped plates

LI Jia-wu, MENG Lu, ZHAO Bo-long, XIAO Tian-bao, LU Bin

Abstract: To evaluate the vortex-induced vibration (VIV) characteristics of a twin-box girder with inverted L-shaped plates, a cable-stayed bridge was used as the research object, a main beam sectional model with a scale ratio of 1∶70 was designed and fabricated. A sectional model vibration system with spring suspension was established in the wind tunnel laboratory, which could perform vertical bending and torsional 2-degree-of-freedom (DOF) motion. By changing the equivalent mass and damping ratio of the vertical bending and torsion of the vibration system, wind tunnel tests for determining vibration were conducted to analyze the sensitivity of the maximum amplitude and lock-in region of VIV to these parameters. By changing the characteristic size of the inverted L-shaped plates, wind tunnel tests for synchronous pressure and vibration measurement were conducted. The surface pressure and vibration amplitude of the model were measured. The distribution characteristics of surface pressure and VIV response were analyzed. The vortex-induced aerodynamic force was calculated, and the correlation and contribution of the local aerodynamic force on the main girder section to the overall aerodynamic force were analyzed. The distribution law of aerodynamic force in the span-wise direction of the model was explored. Analysis results show that changes in mass and damping parameters and aerodynamic shape can alter the VIV response of the twin-box girders. Overall, the maximum amplitude of VIV and the length of the lock-in region are negatively correlated with the Sc number. When the lock-in phenomenon occurs, the correlation coefficient, contribution coefficient, and pulsating pressure coefficient of local aerodynamic force and overall aerodynamic force remain consistent with the amplitude variation law, and the surface pressure and aerodynamic force change synchronously. The span-wise correlation coefficient of wind pressure decreases with increasing span-wise spacing and is closely related to amplitude. The inverted L-shaped plate changes the separation and reattachment position of the airflow, thereby suppressing the occurrence of VIV. Its aspect ratio is a key parameter for the vibration suppression effect.More>

2025, 25(3): 101-113. doi: 10.19818/j.cnki.1671-1637.2025.03.006

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Force performance of steel-concrete sections in railway double-box hybrid girder cable-stayed bridge

KANG Wei, LI Wei, WEN Qiang, CHENG Gao, FANG Shuai-ping, MENG Xiang-jian, LIU Yong-jian, WEN Bo-hua

Abstract: To study the force performance and force transfer mechanism of railway double-box hybrid girder cable-stayed bridge and optimize its construction form and size, the front pressure plate, steel beam embedded section, and steel compartment in the preliminary design of the real bridge were canceled, and the density of the shear connector was minimized. A test model with a scale ratio of 1∶2.5 was then designed and constructed for the steel-concrete sections. The stress distribution, bearing performance, and shear transfer characteristics of the combined section were analyzed under calculation conditions of each real bridge design. The shell-solid finite element model was built to further analyze parameters including the effect of the combined section length, front pressure plate, and shear connector. Research results show that with the simplified structure, the scale model of the railway double-box hybrid girder cable-stayed bridge has seen a good linear correlation in the load-stress curve of all the measuring points under the influence of axial pressure and maximum positive/negative bending moment. The force of the steel-concrete joint section is still in the elastic stage. The load-slip relationship of the slip measuring point of the steel-concrete interface is approximately linear change, with a maximum slip value of 0.15 mm. The residual slip upon unloading can be ignored. There is also a cooperative force between the steel plate and concrete. Under the axial pressure condition, the shear force of the steel-concrete joint interface shows a horseshoe-shaped distribution featuring large ends and small middle. The larger the combined section length, the smaller the interface shear and relative slip. When the combined section length exceeds 2 times of the shear transfer length, the regional shear force and relative slip between the steel beam and the concrete beam are almost zero. The rear pressure plate, front pressure plate, and steel beam embedded section bear about 56.0%, 12.4%, and 11.0% axial force, respectively. The front pressure plate and steel beam do not change the positive stress change trend and axial force distribution characteristics of the steel structure and concrete in the steel-concrete section. No significant effect can be seen on the stress and force transfer of the steel-concrete section. The stress concentration at the rear pressure plate and the steel roof and bottom plate can be improved by the transverse partition plate.More>

2025, 25(3): 114-129. doi: 10.19818/j.cnki.1671-1637.2025.03.007

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Bayesian decision method of inspection and maintenance planning for deteriorating RC bridges

WANG Xiao-ming, WANG Fan, ZHAI An, ZHAO Jian-ling

Abstract: In order to determine the optimal inspection and maintenance plan for deteriorating reinforced concrete (RC) bridges and achieve the best balance between structural reliability level and life cycle cost, a Bayesian decision method based on risk-based inspection (RBI) was proposed. Based on the theoretical deterioration model of RC bridges in a chloride-ion erosion environment, a quantitative index system for corrosion damage assessment was developed. A stochastic deterioration process model and a reliability updating method based on a dynamic Bayesian network were established. By comprehensively considering the uncertainties of environmental parameters, damage detection, and maintenance decisions, the Bayesian network was expanded by introducing decision nodes describing inspection actions and utility nodes quantifying expected costs and benefits. A inspection and maintenance decision system based on a limited memory influence diagram (LIMID) was formed. The proposed method was applied to the inspection and maintenance planning of the RC bridge deck of an in-service composite girder bridge. Analysis results show that the theoretical corrosion failure probability of the bridge deck increases significantly with the extension of service life, reaching 19.4% and 45.5% in the 40th and 60th years, respectively. Necessary maintenance measures are urgently needed. By using the method in this article for inspection and maintenance planning, the optimal inspection times are obtained as the 18th, 33rd, 48th, and 61st years. The expected relative total cost is 260.3, including an inspection cost of 0.769, a maintenance cost of 187.8, and a failure cost of 71.7. Compared with the actual maintenance plan of the bridge, the cost is reduced by 36.3%. The relative total cost under the periodic inspection (PI) method is 271.1, and that under the reliability threshold (RT) method is 270.4. The proposed method provides an optimal solution.More>

2025, 25(3): 130-143. doi: 10.19818/j.cnki.1671-1637.2025.03.008

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Long-period design response spectrum study of ultra-long-span suspension bridges

ZHOU Mi, LI Zhi-xuan, FENG Peng-fei

Abstract: To establish the long-period design response spectrum suitable for the seismic design of ultra-long-span suspension bridges, 17 574 measured ground motion records were collected from the strong earthquake databases of China, Japan, and the United States. By correcting, filtering, and analyzing the spectral characteristics of the collected records, a standard and method for defining the conventional ground motion and the long-period ground motion were proposed. Then, 1 084 long-period ground motions were selected by this method.A "four-segment" standardized response spectrum mathematical model was used to fit the average amplitude of the long-period ground motions. The model parameters were calibrated by a genetic algorithm, the long-period design response spectra for different engineering sites were established. An ultra-long-span suspension bridge with a main span of 2 300 m was taken as the support project, the rationality of the proposed spectrum was verified by analyzing the structural response caused by the safety evaluation response spectrum and the long-period design response spectrum.Analysis results show that the average period of the acceleration response spectrum in the range of 0.02-10.00 s is no less than 1.5 s, which can be used as an important criterion with the less-than-1Hz main frequency component of the Fourier spectrum to define the conventional ground motion and the long-period ground motion.Compared with the standard response spectrum, the proposed long-period design response spectra can take the effect of long-period ground motion into more comprehensive consideration. Under E1 earthquake action, the seismic response difference ratio at the key position of the bridge tower in the support project, caused by the long-period design response spectrum and the safety assessment response spectrum, is 1.4%-42.4% while the difference ratio is 0.3%-19.3% under E2 earthquake action. Additionally, under the long-period design response spectrum, the seismic responses of the bridge tower and the stiffened beam are greater than that corresponding to the safety assessment response spectrum. For an ultra-long-span suspension bridge, where key load-bearing components need to maintain elasticity under E2 earthquake action, the proposed long-period design response spectrum can rationally guide its seismic design.More>

2025, 25(3): 144-159. doi: 10.19818/j.cnki.1671-1637.2025.03.009

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Anti-corrosion and deterioration performance of ECC-RC composite structure for shield tunnel segment under chloride attack

ZHAO De-bo, ZHANG Jie-wei, CUI Hong-zhi, BAO Xiao-hua, CHEN Xiang-sheng, CAO Cheng-yong, SHEN Jun

Abstract: To boost the service performance of shield tunnel structure in an underground chloride environment, the engineered cementitious composite (ECC) with excellent cracking resistance were utilized to form an ECC-reinforced concrete (RC) composite structure for segments. The characteristics of single-sided chloride ion attack and sustained-loading coupling of the surrounding rock in the service environment of the tunnel were taken into consideration. A sustained-loading-accelerated corrosion testing apparatus and the eccentrically compressed specimens simulating the working state of the tunnel segment were designed. Electrochemical corrosion experiments and the tests of mechanical properties after corrosion deterioration were conducted on ECC-RC composite and conventional RC segment specimens. The corrosion deterioration rule and uneven corrosion characteristic of the steel bars of the two specimens were investigated at different sustained-loading levels. The mechanism of enhancing anti-corrosion deterioration performance with the ECC external layer was then revealed. Experimental results show that due to the dense structure and micro-cracking properties of the ECC layer, ECC-RC specimens are 6.8-7.2 times higher than conventional RC specimens in the applied voltage under the same current. The steel bar corrosion ratio of ECC-RC specimens is significantly lower than that of conventional RC specimens. It indicates that the shield tunnel segment with ECC-RC composite structure sees a significant increase in the anti-corrosion performance. Deteriorated ECC-RC specimens have higher loading capacity but smaller ultimate deflection than their RC counterparts with the same sustained-loading level. The sustained-loading level highly influences the corrosion deterioration patterns and bearing capacities of specimens. The ultimate bearing capacity of the deteriorated specimens is negatively correlated with the sustained-loading level at the corrosion stage. Compared with the ultimate bearing capacity of the non-deterioration specimens, when the loading capacity increases 1/10, the ultimate bearing capacity of RC tunnel segments drops by 2.6%, while that of ECC-RC composite tunnel segments decreases by 4.2%. The sustained-load steel bar in RC specimens presents significant uneven longitudinal corrosion. Pitting corrosion tends to occur at the location of cracks with sustained loading. The uneven corrosion becomes severer with the higher sustained-loading level. Due to the multiple micro-cracking mode of the ECC layer under sustained loading, the steel bar in ECC-RC specimens shows relatively uniform corrosion.More>

2025, 25(3): 160-177. doi: 10.19818/j.cnki.1671-1637.2025.03.010

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Model test of structural response of end-restricted shield tunnel induced by surface loading and unloading

LIANG Rong-zhu, KANG Cheng, WANG Sen-yong, FU Yu-kun, ZHOU Zheng, MEI Guo-xiong, XIANG Li-ming

Abstract: To investigate the stress and deformation characteristics of end-restricted shield tunnel structures during the loading and unloading process induced by temporary surface surcharge, a physical model test system with a similarity ratio of 1:35 was established. The study analyzes the structural response differences between the end-restricted shield tunnel connecting the station and the interval tunnel during the surface loading and unloading process. To more accurately reflect the stress and deformation characteristics of the shield tunnel, a high-fidelity, staggered-joint, non-dovetail tunnel model was constructed using 3D printing technology to fabricate the shield tunnel segments. The tunnel model was then assembled and connected to the station model. A multi-stage surface loading and unloading test was designed using a rectangular load directly above the station connection. The tunnel's stress and deformation were monitored using strain gauges, displacement meter, and earth pressure box. The development of additional earth pressure, tunnel displacement, segmental internal forces, and cross-sectional deformation was analyzed. Experimental test results show that the additional earth pressure on the tunnel crown during the surface loading and unloading process is unaffected by the connection to the station. The joint ring connecting the station exhibits a smaller bending moment value and a more uniform distribution compared to the loading intermediate ring. The displacement of the tunnel rings in the end-restricted shield tunnel is constrained by the connection to the station, resulting in an asymmetric settlement curve. The settlement at the crown of the joint ring is only 58% of that at the edge ring and just 42.6% of the corresponding crown settlement in the interval tunnel. In the end-restricted shield tunnel, the intermediate ring under loading experiences the largest convergence deformation, while the joint ring's convergence deformation is smaller than that of the edge ring at the symmetric position. The vertical and horizontal convergence of the joint ring in the end-restricted tunnel are similar, whereas in the interval tunnel with a free end, the vertical convergence is significantly greater than the horizontal convergence. The vertical deformation and recovery capacity of the end-restricted tunnel are limited, with the vertical convergence rebound rate of the joint ring being only 3.0%. Compared to the interval tunnel, the end-restricted shield tunnel exhibits smaller structural deformations during the surface loading and unloading process, demonstrating stronger structural load-bearing performance. The research results provide theoretical guidance for the protection of operational shield tunnels.More>

2025, 25(3): 178-191. doi: 10.19818/j.cnki.1671-1637.2025.03.011

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Equivalent AC layer thickness conversion and deflection index correction based on structural negative thixotropic effect

WANG Xu-dong, LI Qian, LIU Xu, CAI Qiu-xiang

Abstract: To reveal the essential law of asphalt pavement structure deflection under instantaneous loads of falling weight deflectometer (FWD), five structures on the RIOHTrack full-scale test track under the same subgrade and base conditions were seen as benchmark structures, and the variation law of asphalt pavement deflection index with thickness under instantaneous impact loads of FWD was analyzed. Based on the principle of equal stiffness, the equivalent asphalt concrete (AC) layer thickness for different base structures of RIOHTrack was derived, and the 19 pavement structures were simplified into a double-layer system consisting of equivalent AC layer + subgrade. A simple design method for asphalt pavement structure based on bearing capacity index was proposed, and a comprehensive correction model for theoretical deflection index was constructed by considering soil modulus and equivalent AC layer modulus of the superstructure. Research results indicate that under instantaneous loads of FWD, asphalt pavement structures have significant negative thixotropic effects. The deflection index shows a decreasing trend with the increase in asphalt layer thickness under the same subgrade and base conditions. This phenomenon has been verified under different load levels and environmental conditions. The correlation between the equivalent AC layer thickness of the pavement structure and the measured deflection basin area is over 99%, which proves that the proposed equivalent AC layer thickness conversion method has good reliability. Compared with the traditional comprehensive deflection correction models, the F correction model proposed considers both the subgrade and the superstructure modulus, thus compensating for the deficiency of existing deflection correction methods that fail to consider the impact of the pavement structure form. The research results can provide a simple and feasible method for the asphalt pavement structure design.More>

2025, 25(3): 192-204. doi: 10.19818/j.cnki.1671-1637.2025.03.012

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Lightweight pavement crack segmentation network with multi-branch feature extraction

LIU Yuan-yuan, CHEN Jia-hao, WANG Jing-zhi, XIAO Qian, ZHU Lu

Abstract: To address the problem in balancing segmentation accuracy and model complexity of road crack segmentation models, a lightweight pavement crack segmentation network, namely, hierarchical multi-branch cascade network (HMBCNet) was proposed. According to the correlation between the number of feature map channels and model computations, a decoupled down sampling module was used to reduce the initial computations and parameters of the network. By exploiting the differences between shallow morphological information and deep semantic information in feature extraction, the multi-branch dilated module and dual-branch inverted residuals module were designed to extract features of the network at different stages. The complexity of the model was reduced and the feature extraction capabilities of the network model at different stages were enhanced by the multi-branch design. Through cascading multiple sub-backbone networks to obtain an encoder, the parameters of the feature extraction module were shared with the feature fusion module. The multi-scale feature fusion capability of the model was thus improved without increasing the total model parameter quantities. Experiments were conducted on the mobile platform NVIDIA Jetson AGX Orin edge device using the self-built dataset and publicly available datasets (Crack500, DeepCrack537). The accuracy, recall, F₁-score, intersection over union, and precision were taken as the evaluation metrics for model segmentation performance. The degree of model lightweight was assessed based on parameter quantities, computation, and running speed. The proposed HMBCNet was compared with LightCrackNet and seven other representative models. Analysis results indicate that across diverse datasets, the segmentation accuracy of HMBCNet is higher than LightCrackNet and the other seven models, and parameter quantities and computations significantly reduce. HMBCNet has only 1.44×10⁶ parameter quantities and 2.93 GFLOPs computations, 63% lower than LightCrackNet in computations and 1% higher in the F₁-score. The average processing time per image during testing reaches 211 ms. HMBCNet proves to be an effective network model that balances accuracy and complexity, suitable for practical engineering applications.More>

2025, 25(3): 205-220. doi: 10.19818/j.cnki.1671-1637.2025.03.013

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Theoretical analysis of screw pile under individual thread shear failure pattern

LUO Li-juan, MA Jia-kuan, HU Zhi-ping, LI Sheng, HE Peng-yuan

Abstract: To address the problems of calculating the critical pitch of screw piles and the ultimate bearing capacity provided by threads under an individual thread shear failure pattern in high-speed railway subgrade engineering, the locally unfolded region of screw piles was taken as the research object. Research on the individual thread shear failure pattern under ultimate load was carried out. Based on the structural stress characteristics of the thread, a theoretical failure model was established by dividing the surrounding soil into an elastic compaction zone, a passive failure zone, and a transition zone. Through analysis of stress-deformation compatibility relationships in different regions, the ultimate bearing capacity provided by the thread was derived. Corresponding calculation methods for critical pitch and ultimate bearing capacity were developed according to the proposed theoretical failure model of the thread. The validity and accuracy of the model were verified through comparative analysis with existing failure models and large straight shear experiments. Research results show that the individual thread shear failure pattern proposed by the research demonstrates better agreement with the actual failure mode of the thread compared to the Meyerhof failure pattern. The critical pitch of the screw pile is primarily determined by the height of the thread and the internal friction angle of the soil, exhibiting nearly linear variation with the height of the thread and approximately exponential growth with the friction angle. The bearing capacity provided by the thread under the individual thread shear failure pattern surpasses that of the cylindrical shear failure pattern, with the improvement magnitude mainly governed by soil failure surface geometry and shear strength. During screw pile design, appropriately increasing the height of the thread and pitch while ensuring the structural safety of the thread can optimize the surrounding soil to achieve the individual thread shear failure pattern, thereby maximizing the ultimate bearing capacity of the screw pile. The research results provide a theoretical reference for the ultimate bearing capacity optimization design of screw piles in high-speed railway subgrade engineering under silt and clay geological conditions.More>

2025, 25(3): 221-230. doi: 10.19818/j.cnki.1671-1637.2025.03.014

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Valve-controlled semi-active lateral vibration reduction system for high-speed EMUs and tests

SHI Huai-long, GAN Feng, ZENG Jing, FENG Yong-hua, LUO Ren, WANG Yong, WU Yi

Abstract: To ensure the lateral ride comfort of high-speed EMUs running across the existing passenger transport line (160 km·h^-1), speed-up line (250 km·h^-1), and high-speed passenger transport line (350 km·h^-1), a semi-active lateral vibration control system was designed based on the sky-hook damping principle and valve-controlled semi-active damper. The bench test and line test were performed. A test was first carried out for the dynamic performance, valve-control characteristics, and response time delay of the valve-controlled semi-active damper. A rolling and vibration bench test was carried out to analyze the control effect under three types of track excitation. Furthermore, a low-speed line test was performed to evaluate the improvement effect of lateral vibration of the car body. The results show that the measured response time delay of the semi-active control system is about 140 ms. A time delay compensation method is then proposed based on vibration prediction, which can compensate time of 1/4 vibrating cycle. The bench test verifies the validity and necessity of the time delay compensation. The rolling vibration and bench test with different track spectra and vehicle speeds demonstrates the effectiveness of constant damping, on-off damping, and continuous damping control strategies. The lateral ride comfort index can be improved up to 19% and the bandwidth of vibration reduction is 1-20 Hz. The improvement effect gets better with higher vehicle speed and worse track spectrum. According to the line test, the semi-active damping system has significantly restrained the low-frequency vibration below 2.5 Hz on the car body. The improvement rate of the ride comfort index is 11% at 160 km·h^-1. The findings can provide theoretical and technical support for the application of active suspension technology, thus promoting the performance improvement of existing EMUs and the innovative design of higher-speed EMUs.More>

2025, 25(3): 231-241. doi: 10.19818/j.cnki.1671-1637.2025.03.015

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Comparison of thermal dissipation performances between carbon-ceramic and cast steel brake discs for high-speed train

ZUO Jian-yong, ZHENG Shi-ze, WANG Tian-yi, DING Jing-xian

Abstract: To investigate the braking thermal dissipation performance of traditional cast steel brake discs and new carbon-ceramic brake discs used for high-speed trains at an initial braking speed of 400 km·h^-1, complex front head models of high-speed trains containing carbon-ceramic brake discs and cast steel brake discs were established. An air domain was constructed around the front model. A fluid-solid-thermal coupling simulation method was used to analyze and compare the temperature changes of carbon-ceramic brake discs and cast steel brake discs under emergency braking conditions and their effects on the surrounding air domain. Temperature-related bench tests were also conducted for carbon-ceramic brake discs and cast steel brake discs to verify the accuracy of the simulation. Simulation results show that under an initial braking speed of 400 km·h^-1, the friction surface temperature of the carbon-ceramic brake disc reaches a peak of 1 098.56 K at 86.3 s after braking starts. The overall temperature change trend of the cast steel brake disc is similar to that of the carbon-ceramic brake disc, and their peak friction surface temperature reaches 1 019.26 K at 73 s after braking starts. However, the carbon-ceramic brake disc has a greater impact on the temperature changes in the surrounding air domain, which may pose thermal safety risks in the bogie area of high-speed trains, and the maximum temperature difference between the two air domains can reach 210 K. Compared with the cast steel brake disc, the material and structure of the carbon-ceramic brake disc allow for a faster internal heat conduction rate, a more uniform temperature distribution on the friction surface, and a smaller temperature gradient between different radial areas, resulting in better thermal performance. However, the carbon-ceramic brake disc has a greater impact on the temperature changes in the surrounding air domain, which may pose thermal safety risks in the bogie area of high-speed trains. The comparative results of the bench tests show that the fluid-solid-thermal coupling simulation model of the high-speed train front containing brake discs can accurately predict the trend of temperature changes during braking and can generate detailed temperature change cloud maps.More>

2025, 25(3): 242-255. doi: 10.19818/j.cnki.1671-1637.2025.03.016

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Influence of different internal and external coupling excitations on dynamic characteristics of high-speed railway gearbox housing

ZHANG Jian-chao, ZHANG Bo-wen, QI Xing-ke, ZHANG Yong-chao

Abstract: The changes in housing vibration acceleration and the influence on various parts of the housing from dynamic stress were interpreted from the perspectives of probability statistics and fatigue damage. Based on vector control theory and multibody dynamics theory for locomotives, a traction motor control model for high-speed train and a rigid-flexible coupling model of high-speed train with a flexible housing were established. The mechatronic coupling model of the high-speed train was constructed through joint simulation. The probability density function curve of housing vibration acceleration was fitted using kernel density estimation. Combined with fatigue testing of housing materials, the damage parameters were calculated. Analysis results show that the probability density functions of vibration acceleration above the small bearing hole in the longitudinal direction, and above the large bearing hole in the horizontal and vertical directions, all undergo a process of changing from a single peak to double peaks. The probability density graphs gradually widen and flatten, indicating that the vibration acceleration in these three directions is significantly affected by excitation changes. When the probability density function exhibits double peaks, they all include wheel polygonal excitation, suggesting that this excitation leads to a more concentrated distribution of vibration acceleration signals on both sides. The fatigue damage contribution from harmonic torque excitation above the small bearing hole and at the oil level observation hole is more prominent, with the damage parameters increasing by about 0.05 at these two locations. These damage parameters remain almost unchanged with the change in working conditions. The fatigue damage contribution from track irregularity excitation above the large bearing hole is the largest, with the damage parameters increasing from 0.14 to 0.68. The fatigue damage contribution from wheel polygonal excitation at the tooth surface observation hole is larger compared to other excitations, with the damage parameters increasing from 0.19 to 0.60. The change in damage parameters at the large bearing hole and the tooth surface observation hole is more significant, so special attention should be given to these areas during maintenance.More>

2025, 25(3): 256-268. doi: 10.19818/j.cnki.1671-1637.2025.03.017

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Research on suspension model switching preview control based on road surface vertical excitation game decision

WU Xiao, CHEN Zhi-yong, CHEN Long, LIU Qiao-bin, YANG Hong-bo, SHI Wen-ku

Abstract: To address the inconsistency between apparent road surface roughness and actual vertical road excitation, a game theory-based vertical road excitation perception and decision-making method was proposed for preview control of the suspension model, aiming to improve the ride comfort of vehicles under complex road excitation conditions. Based on optimal suspension control theory, a multi-objective optimization algorithm was used to optimize the control models for different road excitation patterns. By integrating the control models under all excitation patterns, a suspension model switching control system was established. The controller parameters were switched according to vertical road excitation so that the vibration state of the suspension was kept optimal. The vibration responses under the same road excitation and different controller parameters were compared, and the influence of controller parameters on vibration responses was analyzed. Suspension control was regarded as a game between the controller and the road excitation. To improve ride comfort, when the results of the road preview method and the state observation method were contradictory under different road excitations, the optimal result was analyzed based on game theory and used as the basis for suspension control model switching. Analysis results show that based on the game theory, the control system should switch the control model according to the power spectral density index or road amplitude to improve ride comfort. Compared with the pure preview control model without game theory, on continuous road surfaces, when the preview result is grade A, and the state observation result is grade D, the root mean square (RMS) of vehicle acceleration of the optimal control model based on the game theory decreases by 14.24%. On the impact road surfaces, the peak value of the vehicle acceleration decreases by 5.86%. On mixed road surfaces, the RMS of the vehicle acceleration decreases by 11.60%, and the RMS of suspension's dynamic deflection, tire's dynamic travel, and energy consumption all increase by less than 10%. This method is applicable to improving the ride comfort of vehicles equipped with preview suspension systems under various complex road conditions.More>

2025, 25(3): 269-283. doi: 10.19818/j.cnki.1671-1637.2025.03.018

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Weight balance problem modeling and two-stage Benders decomposition heuristic algorithm design of non-ULDs

LI Yun-fei, XU Ji-hui, ZHAO Xiang-ling, HUANG Ji, TONG Zi-chen

Abstract: To explore the potential of loading non-unit load devices (non-ULDs) in civil aviation cargo aircraft, the weight balance problem (WBP) of loading non-ULDs in cargo aircraft was studied. The differences between loading non-ULDs and ULDs in WBP were compared. The cargo hold was regarded as a rectangular plane and the non-ULDs as rectangular items, a two-stage weight balance optimization model was constructed for loading non-ULDs. In the two-dimensional geometric constraint model in the first stage, constraints of non-ULDs were considered such as no overlapping, not exceeding the cargo hold boundaries, and orthogonal rotation. The maximum utilization of the aircraft cargo hold plane area was taken as the objective function. In the weight balance model in the second stage, constraints of various aircraft were considered such as weight and stability. The maximum payload and minimum center of gravity (CG) deviation were selected as the multi-objective function. The Benders algorithm was designed and used based on logical decomposition. The WBP of cargo aircraft loading non-ULDs was decomposed into a master problem and a sub-problem. The master problem used improved genetic simulation and the lowest horizontal line algorithm to determine the loading sequence and position of non-ULDs. The sub-problem employed the y-check algorithm to check various constraints, such as weight and stability. The Benders' cut constraint model was provided. The two scenarios where the area of non-ULDs was greater than and less than the cargo hold area were designed. The model was verified and compared using four methods: the proposed algorithm, Gurobi^*, Gurobi, and expert stowing for two different loading constraint requirements. Experimental results show that, when testing a two-dimensional geometric position allocation model for left-right balance in the cargo hold, Gurobi^* achieves the best solution quality and speed. The average payload, cargo hold area utilization rate, CG deviation, and solution time are 19 872 kg, 65.88%, 2.08%MAC and 61.18 s, respectively. The expert stowing method is the worst, with its average payload, cargo hold area utilization rate, CG deviation, and solution time reaching 18 494 kg, 65.21%, 2.79%MAC, and 986.98 s, respectively. As a heuristic algorithm, the proposed algorithm gets an average payload of 18 874 kg, slightly worse than the optimized solutions of Gurobi^* and Gurobi. The average cargo hold area utilization rate and CG deviation are 71.87% and 2.76%MAC, respectively. The average solution time is 175.97 s, much faster than Gurobi's of 1 082.92 s. The proposed two-stage weight balance optimization model and algorithm can provide a reference for determining the loading positions and directions of non-ULDs.More>

2025, 25(3): 284-303. doi: 10.19818/j.cnki.1671-1637.2025.03.019

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Research on optimal design of human-machine interaction interface of remote navigation and control ships

LI Meng-xia, XU Tu-yuan, ZOU Tian-yue, LIU Chen-guang, ZHENG Mao, CHU Xiu-min, YAN Xin-ping

Abstract: To ensure the safety and reliability of ship remote navigation, an optimization method for the human-machine interaction (HMI) interface for remote navigation and control ships was proposed. The changes in visual attention distribution during the remote-controlled operation conducted by remote operators were deeply investigated. The HMI interface was optimized by considering the evolution patterns of viewpoint time series and the importance of interface partitions. By analyzing the distribution of viewpoint time series in sub-interfaces, the evolution patterns of viewpoint time series were extracted. The logical relationship and influence degrees among sub-interfaces were established, and the importance of each sub-interface was quantified based on the degree of mutual influence. According to the evolution patterns of viewpoint time series and the importance of interface partitions, the position relationship, arrangement order, and interface proportion of each partition of the HMI interface were determined, thus realizing the optimization of the HMI interface for remote navigation and control ships. Turning and overtaking scenarios of remote navigation and control ships were tested in Fengjie, Chongqing. Analysis results show that in terms of the evolution patterns of viewpoint time series during remote navigation, the viewpoint accounts for nearly 50% of the transitions between the "bow perspective" and the "operating conditions of remote-controlled ships". In the interface importance analysis, the total proportion of viewpoint distribution in these two interfaces accounts for nearly 70%. The proposed method is applicable to the optimized design of HMI interfaces for remote-controlled ships and can provide the corresponding optimized design schemes for such ships with different levels of intelligence.More>

2025, 25(3): 304-316. doi: 10.19818/j.cnki.1671-1637.2025.03.020

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GNSS interference detection method based on combined processing of civil aviation ADS-B multi-quality indicator and multi-features

CHEN Min, ZHU Tong-hui, HE Wei-kun, LU Jian-bo, ZHOU Hong

Abstract: To solve the issue of weak navigation satellite signals, which were highly susceptible to various intentional or unintentional interferences that pose aviation safety risks, cause flight delays, and reduce operational efficiency, the abnormal trajectory caused by global navigation satellite system (GNSS) radio frequency interference and the variations in navigation quality indicators in automatic dependent surveillance-broadcast (ADS-B) data were utilized, a GNSS interference detection method based on the joint processing of multiple quality indicators and features of ADS-B data was proposed, which was compatible with various quality indicators from DO-260, and DO-260A/B. In a GNSS interference environment, variation features from ADS-B data were extracted. Potential interfering flights were identified by detecting abnormal behaviors such as the fluctuation duration of navigation quality indicators, simultaneous quality indicator changes with trajectory breakage, and simultaneous decreases in multiple quality indicators. The potential interfering flights were further analyzed by extracting interference feature points. Considering the spatial aggregation of interfering flights, the MeanShift clustering method is then used to detect the interfering flights. Experimental results show that the proposed GNSS interference detection method based on joint processing of multiple quality indicators and features improves precision by 21.3% compared to single quality indicator methods, effectively reducing the false detection rate. Compared to the entropy weighting method, the recall rate improves by 7%, and the method can effectively reduce the miss detection rate without increasing the false detection rate. Furthermore, this method does not require large datasets for pre-training and reduces detection time by 98.4% compared to machine learning methods, offering better real-time performance and engineering application value. It can provide solutions for determining the interfering flights, interference times, and locations in civil aviation radio interference detection.More>

2025, 25(3): 317-329. doi: 10.19818/j.cnki.1671-1637.2025.03.021

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Mechanism for identifying and resisting cache pollution attack in vehicular named data networking

FAN Na, LI Jia-long, GAO Yu-xin, ZHANG Jun-hui, YE Li-ping

Abstract: To accurately detect and effectively resist cache pollution attacks in vehicular named data networking, an adaptive attack detection and resistance mechanism based on deep reinforcement learning was proposed by integrating the prediction of content popularity. A network state judgment method using support vector machine was designed for the characteristics of cache pollution attack. When an abnormal state was identified, the functions of detection and resistance of cache pollution attack were triggered. Meanwhile, an adaptive attack detection method was developed by combining deep Q-network and the K-means algorithm. With this method, the time interval for attack detection was dynamically adjusted based on network characteristics. The roadside unit could filter the false popular content generated by cache pollution attacks based on the predicted content popularity and request records of vehicle nodes, thereby achieving precise and rapid attack detection. In addition, a method for resisting cache pollution attacks was proposed based on the dynamic blacklist. The false popular contents generated by the attack were placed on the blacklist, which was dynamically updated based on the detection results. Vehicle nodes and roadside units removed the false popular contents from the cache according to the blacklist and discarded the corresponding interest packets. Therefore, the cache pollution attack was effectively suppressed and its impact on users was also reduced. Semi-physical simulation platform was constructed. The detection performance of the proposed method against cache pollution attacks was further verified by a semi-physical simulation test. Simulation test results show that when facing high-intensity cache pollution attacks, the proposed method detects cache pollution attacks with accuracies of 0.91 and 0.92, respectively, in low-density and high-density vehicular named data networking scenarios. The content retrieval delays for vehicle nodes decrease to 0.113 and 0.112 s, respectively. The performance of the proposed method is superior to existing methods. It can effectively identify and resist cache pollution attacks, and improve the security of vehicular named data networking.More>

2025, 25(3): 330-345. doi: 10.19818/j.cnki.1671-1637.2025.03.022

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Eco-driving trajectory optimization model at signalized intersection considering shared phase

XIN Qi, WANG Jia-qi, FU Rui, XU Meng, ZHOU Hai-yang, PAN Ying-jiu

Abstract: A dynamic programming-intersection conflict management strategy was proposed to optimize the trajectories of intelligent connected vehicles approaching signalized intersections under shared phase conditions and mitigate conflicts at intersections. A dynamic programming model was established based on the information of vehicle state and signal phase and timing to optimize the trajectories of vehicles upstream of the signalized intersection, maximize throughput during green time, and reduce waiting time. Besides, an intersection conflict management strategy was designed for the shared phase scenario with traffic conflicts. The strategy determined the sequence of conflicting vehicles passing through the intersection by virtual vehicle mapping and created a safe gap by an intelligent driver model, ensuring smooth traffic flow within the intersection. Finally, a simulation analysis was conducted on the signalized intersection of Yongqing Road and Yonglong Road in Xi'an City. Simulation results show that in contrast to left-turn protected phase and shared phase scenarios under the control of the dynamic programming model, the proposed model improves average speed by 12.88% and 4.14% and reduces energy consumption per 100 km by 9.79% and 3.97%, respectively. Compared to the scenario with 0% penetration rate, the total energy consumption per 100 km under the proposed model decreases by 3.56%-13.97% in scenarios with penetration rates ranging from 20% to 100%. Analysis of the time to collision and post-encroachment time under the proposed model shows a significant improvement in safety. Furthermore, under conditions of varying traffic demands and fluctuating signal cycles, the proposed model can achieve trajectory optimization for vehicles throughout the entire process from entering the lane to leaving the intersection.More>

2025, 25(3): 346-361. doi: 10.19818/j.cnki.1671-1637.2025.03.023

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Wind speed prediction along high-speed railway based on multi-time-interval wind speed fluctuation process division

ZHANG Ying-chao, AN Ran, CHEN Xin, YE Xiao-ling, XIONG Xiong

Abstract: To improve the accuracy of wind speed prediction along high-speed railway, realize prediction and warning, provide a sufficient time window for high-wind dispatch, and ensure the operation safety of the high-speed railway in high-wind scenarios, a wind speed prediction method for multi-temporal attention deep echo state network along the high-speed railway based on wind speed fluctuation process division (MT-RFVMD-OD-Fu-Attention-DeepESN) was proposed. By using sampling data of second-level and three-minute wind speed of wind speed monitoring stations along the high-speed railway, as well as the improved radio frequency variational mode decomposition (RF-VMD), the wind speed signals of two resolutions were decomposed and reconstructed into trend components and pulsation components. The frequency analysis was performed by continuous wavelet transform (CWT) to find the variation cycle and divide the two components into time series units of equal length. The clustering algorithm of physical characteristics of wind speed in the units and K-shape fusion was used to divide the two groups of trend components into processes to form a database for wind speed fluctuation processes. Finally, an algorithm for similarity-optimized dynamic time warping (Op-DTW) was designed. The algorithm was used to select wind speed time series fragments with high similarity at two resolutions in the fluctuation process database as training sets, which were input into the designed multi-temporal attention deep echo state prediction network (Fu-Attention-DeepESN). The experiment was verified by using wind speed monitoring data from three wind speed stations along the Beijing-Shanghai high-speed railway and compared with the existing popular methods for wind speed prediction. Analysis results show that the root mean square errors (RMSEs) of wind speed prediction in stations K1005, K1245, and K1066 were 0.234, 0.282, and 0.306, respectively, and the mean absolute percentage errors (MAPEs) were 2.76%, 2.27%, and 2.99%, respectively. The positive wind speed errors (PWSEs) were 0.008, 0.021, and 0.034, respectively. Compared with those of the best of the compared methods, the evaluation indices RMSE, MAPE, and PWSE of the proposed method are reduced by 27.8%, 34.6%, and 27.1% on average, respectively. This proves that this study can effectively handle the complex and non-linear patterns in the second-level wind signals along the high-speed railway and improve the prediction accuracy and adaptability.More>

2025, 25(3): 362-379. doi: 10.19818/j.cnki.1671-1637.2025.03.024

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Slack effect test at exit of extra-long highway tunnels

YANG Yong-zheng, DU Zhi-gang, YU Liang, MAI Jing

Abstract: To study the influence of the slack effect at the exit of extra-long highway tunnels on traffic safety, a vehicle test was carried out. Data on the luminous environment, vehicle speed, and pupil area and attention distribution of drivers were collected to explore the mechanism of the slack effect. Multiple control scenarios were set up to conduct driving simulation tests. The lag effect of the slack effect in the post-tunnel zone was discussed, and the influence distance and harm of slack effect were further analyzed. Analysis results show that, the illumination at the tunnel exit increases rapidly, the pupil area changes quickly, and the white hole effect occurs. While the luminous environment undergoes drastic changes, abnormal phenomena appear such as reduced driver attention and increased vehicle speed. The slack effect at the exit of an extra-long tunnel is thus verified. The slack effect is coupled with the white hole effect, which leads to abnormal driver attention and vehicle speed, along with visual disorder, posing a serious threat to driving safety. In the departure and the post-tunnel zones after the tunnel exit, drivers are still affected by the slack effect. Compared with ordinary roads, drivers in the post-tunnel zone have their attention reduced by 4.2% to 9.0%. Their reactions become slower, and ability to control vehicles decreases. The complex road alignment, such as curves and longitudinal slopes at the tunnel exit, can amplify the harm of the slack effect. Slack effect causes a delay of 80 m in the deceleration position before entering the curve, an increase of 5.7 km·h^-1 in the average speed of passing through the curve, a delay of 50 m in the track change position before entering the curve, and an increase of 7.1 cm in the trajectory offset of passing through the curve. It also brings a delay of 35 m in the acceleration distance after entering the longitudinal slope and an increase of 7.0 km·h^-1 in the average speed of passing through the longitudinal slope.More>

2025, 25(3): 380-392. doi: 10.19818/j.cnki.1671-1637.2025.03.025

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Real-world carbon dioxide and atmospheric pollutant emission characteristics of inland waterway ships

XIONG Yu-qi, FAN Ai-long, YAN Jun-hui, ZHANG Yong-bo

Abstract: A ship emission measurement system was established using portable emissions measuring system (PEMS), global positioning system (GPS), shaft power meters, temperature and humidity sensors, and other instruments. The real-world characteristics of carbon dioxide (CO₂) and air pollutant emission from inland ships were investigated, enabling high-precision measurement of energy consumption and emission data during ship operation. Based on the constructed system, onboard measurement tests were conducted on three major types of inland ships. The energy consumption and emission data of the ships during operation were collected. The steady-state tests of the main ship engine were performed at load conditions of 25%, 50%, and 75% to measure stable energy consumption and emissions. Based on the collected data, the emission factors of gases were analyzed with the carbon balance method. By combining the main engine power data, the characteristics of actual CO₂ and air pollutant emissions from the ships were analyzed. Analysis results show that the main engine load of ships during operation is mostly below 50%. This prolonged low-load operation is the primary cause of increased CO₂ and air pollutant emissions. The power-based emission factors for carbon oxide (CO) and CO₂ are found to be higher during docking and departure than during cruising or maneuvering. When the main engine is in a steady state, the emission of CO₂ and air pollutants is significantly related to engine load and fuel type and decreases with the higher engine load. At relatively high and stable engine load levels, nitrogen oxide (NO_x) emissions are reduced.More>

2025, 25(3): 393-406. doi: 10.19818/j.cnki.1671-1637.2025.03.026

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2025 Vol. 25, No. 3

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