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2026 Vol. 26, No. 1

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Cover and Contents of Vol.26, No.1, 2026
Review
Review and prospect on management of transportation and vehicle engineering discipline under NSFC in 2025
WANG Zhi-zhong, YIN Yin, LI Zhi, CHEN Jun-jie
Abstract: The transportation and vehicle engineering discipline under the National Natural Science Foundation of China (NSFC) focuses on the economic development and the national major strategic demands, continuously strengthens "demand-driven and problem-oriented" research, and conducts systematic, transformative, disruptive and leading studies. The discipline can rapidly break through the "technical gap" between basic research and its practical application through organized scientific research and the aggregation of disciplinary forces. This paper provides an overview of the application, acceptance, and funding status NSFC projects in the discipline of transportation and vehicle engineering in 2025. Guided by major and key projects, the typical cases of systematic, disruptive, and original research within the discipline are analyzed, and the priority funding areas and key project guidelines for 2026 are interpreted. For 2026, the discipline plans to prioritize funding for the following areas: design and control of new high-efficiency transport vehicles, collaborative operation/management of multiple transport vehicles, end-to-end autonomous driving testing for transport vehicles, integrated design of aircraft and their flight control, key technologies/equipment for reusable space transportation systems/on-orbit refuelling, as well as integrated low-altitude traffic planning and coordinated operation within comprehensive three-dimensional transportation networks.More>
2026, 26(1): 1-7. doi: 10.19818/j.cnki.1671-1637.2026.145
Theoretical advances and application challenges of sustainable aircraft taxiing technology
TANG Tie-qiao, CAO Feng, WANG Peng, WANG Tao, YAN Na
Abstract: The main types and technical pathways of sustainable aircraft taxiing technologies were outlined. By focusing on single-engine taxiing, dispatch towing taxiing, and onboard system taxiing, the operating principles, operational procedures, and key control points of different taxiing technologies were clarified. Theoretical research progress on sustainable taxiing technologies was reviewed, including environmental performance modelling and evaluation, physical characteristic analysis, and system design. The fuel consumption and pollutant emission measurement methods of different taxiing technologies during the taxiing phase were extracted. Based on engineering practices at Chinese and international airports and airlines, the current application status of sustainable taxiing technologies was discussed, and differences among technologies in terms of operational efficiency, equipment compatibility, and operational complexity were discussed. On this basis, the limitations and applicability conditions of existing sustainable taxiing technologies were comprehensively evaluated from the perspectives of technical performance, cost effectiveness, operational safety, and applicable scenarios. The promotion and application of relevant technologies were summarized in the context of civil aviation operations in China. The results show that sustainable taxiing technologies have significant potential to reduce fuel consumption, carbon emissions, and noise pollution during the aircraft taxiing phase. Clear differences exist among technologies in terms of energy-saving and emission reduction effects, as well as operational characteristics. Single-engine taxiing shows advantages of low implementation cost and relatively mature operating procedures, and it is suitable for promotion within existing operational systems. Dispatch towing taxiing and onboard system taxiing further reduce the operating time of main engines and achieve more pronounced energy-saving and emission reduction effects, but they impose higher requirements on equipment conditions and operational organization. Overall, large-scale application of sustainable taxiing technologies remains constrained by technical maturity, economic feasibility, operational management complexity, and regulatory certification. The technologies should be promoted through technology-specific pilot implementation and standard development in accordance with airport operating environments and aircraft fleet structures.More>
2026, 26(1): 8-30. doi: 10.19818/j.cnki.1671-1637.2026.01.001
Research review on fire resistance of highway and railway steel truss bridge
ZHANG Gang, DING Yu-hang, XIONG Xin, ZHAO Xiao-cui, LU Ze-lei, WANG Shi-chao, HOU Xu
Abstract: To enhance fire resistance and performance of highway and railway steel truss bridges (also known as a low-carbon bridge) under the combined effects of structural and vehicle loads and extend their full-service life, existing literature was reviewed to examine the trend of bridge fire incidents, and collect bridge fire data and compile statistics on bridge fires, analyze the characteristics of fire incidents of steel truss bridges, and summarize the various causes of such accidents both domestically and internationally. Distinct fire scenarios for highway and railway steel truss bridges were identified. The characteristics of the surface temperature and section temperature rise of the highway and railway steel truss bridges were summarized. A comparative analysis was conducted on the thermal-structural coupling nonlinear analysis methods for bridges under fire exposure conditions. The fire induced failure modes of the highway and railway steel truss bridges were explored, as well as the matters that need to be considered in the fire resistance design methods. Research results show that bridge fire incidents have shown an increasing trend in recent years, and steel truss bridges exposed to severe fire are prone to rapid and progressive collapse. Fire scenarios, load arrangements, member heating, and failure modes in highway and railway steel truss bridges are significantly influenced by their geometric configurations. The lower semi-enclosed space truss structure exhibits series-parallel thermal radiation pathways between members, while the temperature rise of chord members presents heat transfer characteristics of thin-walled and multi-chamber cavity radiation. Key challenges in fire resistance analysis and design include modeling connection between members, buckling failures of components, and time-varying boundary conditions of the structure. Critical issues persist in the fire-exposed highway and railway steel truss bridges concerning scenario reconstruction, rapid assessment, resilience enhancement, and firefighting and rescue. These demands require in-depth research to provide new analytical perspectives and guidance for advancing fire resistance studies and design of such bridges.More>
2026, 26(1): 31-45. doi: 10.19818/j.cnki.1671-1637.2026.01.002
Research review on STGNN in traffic prediction: From model deconstruction to development path
JIA Xing-li, QU Yuan-hai, ZHU Hao-ran, YANG Hong-zhi, YAO Hui, LI Meng-hui
Abstract: To clarify the development path of traffic prediction models and to explore future development directions of traffic prediction, a systematic literature analysis approach was adopted, and a technology development direction dominated by spatiotemporal graph neural networks (STGNN) was established. Based on the framework characteristics of STGNNs, a full-process analysis system was constructed, including data preprocessing, static and dynamic graph construction, spatiotemporal feature extraction, and feature fusion. Typical traffic prediction tasks and their corresponding open-source datasets were systematically reviewed. Static graph construction methods based on topological relationships, distance properties, and similarity calculations were summarized, and frontier graph construction technologies were summarized, including direct optimization of dynamic graphs and feature optimization. Current temporal feature modeling methods and spatial feature modeling methods were analyzed from the two dimensions of time and space, and the spatiotemporal feature fusion mechanism was illustrated through two typical cases of Graph WaveNet and DCRNN. For the problems of gradient anomalies and performance degradation in deep network training, general solutions based on information propagation were summarized. The integration paths of emerging technologies were explored, including contrastive learning, pre-training mechanisms, causal reasoning, and mixture-of-experts models with traffic prediction. Analysis results show that applications of STGNNs in traffic prediction have gradually intensified both domestically and internationally, and China ranks first with 1 671 publications in the statistics. Existing studies are mainly focused on improving model memory ability for spatio-temporal features and constructing optimal graph structures, and such optimization schemes have reached a balance between model performance and efficiency. In temporal modeling, a balance between computational efficiency and operational performance is still being explored, while spatial modeling has become the main obstacle to efficiency improvement of existing models. Based on the summary and review of previous studies, future breakthrough directions are expected to be concentrated on the exploration of novel prediction scenarios, improvement of model interpretability, incorporation of real-world physical constraints, innovation of learning strategies, and exploration of industrial-level deployment solutions, so that stronger technical support is provided for intelligent transportation systems.More>
2026, 26(1): 46-74. doi: 10.19818/j.cnki.1671-1637.2026.01.003
Review on aerodynamic noise and noise reduction technologies of automotive heating, ventilation, and air conditioning system
FANG Yi, CHEN Jie-yan, LI Bai-cheng, ZHAO Yong-ji, SUN Ya-xuan
Abstract: Aiming at the aerodynamic noise problem of the automobile heating, ventilation, and air conditioning system (HVAC), the current research status and research achievements were introduced from the four aspects, including the benchmark duct, the actual ventilation duct, the HVAC system operated in a free field and the system operated inside an automobile. The aerodynamic noise sources and generation mechanisms of the HVAC system were analyzed. The noise reduction measures were discussed for the key components of the HVAC system. The future research directions and development trends were proposed. The results indicated that the main sound sources of noise in the automobile HVAC system are surface dipole sound sources. These sound sources are mainly distributed at the blower impeller, volute, diffuser section, ventilation duct, air flap, and outlet grille. The noise generated by the blower is composed of tonal noise caused by the impeller rotation and broadband noise caused by the interactions between the airflow and surrounding solid surfaces such as the volute. Noise control is achieved through structural optimizations of the impeller and volute tongue, installation of sound-absorbing materials, and implementation of active noise control (ANC) technology. In addition to the propagated noise generated by the upstream blower housing, aerodynamic noise is also generated by the ventilation duct itself. This noise is mainly caused by flow separation or vortex generation induced by internal bends and cross-section variations. Ventilation duct noise reduction is achieved by optimization of the duct configuration to smooth the airflow and reduce local pressure loss, by use of sound-absorbing materials or structures to increase duct transmission loss, and by application of ANC technology to cancel the original noise. At the outlet, noise is generated by the airflow impacting the air flap and grille, and direct radiation toward the human ear is produced. Noise reduction is achieved by adjustment of the outlet shape, by design of bionic grilles, and by installation of ANC devices at the outlet. In addition, a better acoustic environment is obtained by adjustment of the interior materials of the vehicle cabin, and auditory comfort is improved.More>
2026, 26(1): 75-92. doi: 10.19818/j.cnki.1671-1637.2026.01.004
Progress and trends of low-carbon application of waste materials in asphalt pavements
CHEN Lei-lei, ZHU Ji-kai, YE Qin, ZHAO Xin-yuan, QIAN Zhen-dong
Abstract: To promote the low-carbon application of waste materials in asphalt pavement, the application progress was systematically reviewed and analyzed from three dimenisons: waste raw materials, waste-modified asphalt mixtures, and waste asphalt pavements. For waste raw materials, material classification oriented toward carbon reduction, variability, environmental risks, and corresponding treatment methods were summarized. For waste-modified asphalt mixtures, the current status and trends of low-carbon pavement application were reviewed from increased waste incorporation ratios and enhanced mixture durability. For waste asphalt pavements, the feasibility of high-level and full-layer applications of waste materials was explored from the aspects of structural design and construction techniques. It is indicated that waste raw materials possess road application adaptability, but their variability and potential environmental impacts are the key factors restricting large-scale utilization. A multi-source waste classification and grading system and corresponding treatment methods are required. Unstable pavement performance of asphalt mixtures is caused by increased waste incorporation ratios. The mechanisms of performance deterioration caused by waste content and the interaction mechanisms among different waste materials have not yet been clarified. Research on fully waste-based mixtures is still at an initial stage and is an important issue to be addressed in the future. Continuous mechanistic exploration and application practice are still required for durability enhancement techniques for waste-modified asphalt mixtures, especially for performance improvement of waste materials and binders. From the perspective of low-carbon-oriented high-level and full-layer applications, existing asphalt pavement structural designs and construction methods are still in need of improvement. Structural design and construction methods should be modified according to the characteristics of waste materials.More>
2026, 26(1): 93-115. doi: 10.19818/j.cnki.1671-1637.2026.047
Review on research and application technology of marine methanol fuel power system
WANG Kai, LIANG Hong-zhi, LI Zhong-wei, CHI Yan-po, WANG Ya-peng, CAO Jian-lin, HUANG Lian-zhong
Abstract: To address the problems of fragmented research contents and the lack of systematic analysis of a full-chain technical system in existing studies on marine methanol fuel application, a comprehensive analysis was conducted based on the analysis of ship carbon emission control regulations and policies. The research and development status of methanol fuel characteristics and production technologies, methanol fuel storage, transportation, and refueling technologies, methanol power system design optimization technologies, methanol/diesel dual-fuel engine operating characteristics, methanol fuel cell technologies, and methanol fuel risk analysis and operation safety requirements was comprehensively analysed. The shortcomings and challenges in the application technologies of marine methanol fuel power systems were summarized. The future development trends of application technologies of marine methanol fuel power systems were summarized and prospected. Important references were provided for the research and application of key technologies of marine methanol fuel power systems. Analysis results indicate that the methanol fuel application is one of the important options for achieving ship decarbonization targets. Further demonstration and analysis are still required in terms of economy, safety, and full life-cycle carbon emissions. In the future, continuous breakthroughs are required in technologies including green methanol production, safe fuel storage and transportation, fuel leakage and corrosion prevention, endurance improvement, and engine performance optimization and control, thus promoting the low-carbon development of the shipping industry and meeting the requirements of increasingly stringent ship carbon emission regulations.More>
2026, 26(1): 116-131. doi: 10.19818/j.cnki.1671-1637.2026.055
Review on structural mechanics performance of MARK Ⅲ cargo containment system for LNG carrier
GAO Da-wei, LI Cheng, SHI Gui-jie
Abstract: To provide a reference for the research and manufacturing of the cargo containment system (CCS) for liquefied natural gas (LNG) carriers, research achievements on the structural mechanics of the MARK Ⅲ CCS were summarized. The structural composition, material application, manufacturing process, testing methods, and theoretical approaches were outlined. From the aspects of standard specimen tests, static mechanical performance, alternating load performance, and impact load performance, research progress related to the MARK Ⅲ cargo containment system was reviewed. The mechanical properties of key components, including the stainless-steel membrane, laminated plywood, insulation foam, and secondary barrier were analyzed. Existing deficiencies in research objects and methods were identified, and suggestions for future research were proposed. It is indicated that static loads, impact loads, and fatigue loads caused by wind and waves during navigation under normal operating conditions can be withstood by the MARK Ⅲ CCS. Brittle fracture failure in stress concentration areas of the CCS may be caused by severe sloshing impact under low-temperature conditions due to cargo leakage. It is indicated that the dynamic characteristics under actual sailing sea conditions are not fully considered in the current drop-weight impact test method. Future work should be focused on the evaluation and transformation of cargo impact loads and on experimental methods for water impact. The MARK Ⅲ CCS is identified as a membrane-type containment system and is characterized by the absence of additional supporting structure. Compared with MOSS-type and SPB-type cargo containment systems, smaller volume and lower mass are achieved, and higher transportation economic efficiency is obtained. Future development of membrane-type CCS should be focused on indicators such as reduced thickness, low mass, integration, and high load-bearing capacity. Existing research on laminated plywood and the secondary barrier is mainly focused on the mechanical properties of standard specimens, lacking real-ship application scenarios under complex loading conditions. Future research should be conducted based on actual ship structures, and the mechanical performance of laminated plywood and the secondary barrier should be tested accordingly. A review of the structural mechanical performance of the MARK Ⅲ CCS is provided, and a reference for future research and the formulation of relevant standards is offered.More>
2026, 26(1): 132-157. doi: 10.19818/j.cnki.1671-1637.2026.056
Application review on FMEA/FMECA in marine engineering
WANG Jin-long, MA Yu-xin, BAO Yong-jie, JI Xiu-kun
Abstract: The basic framework of FMEA/FMECA was summarized in detail. The similarities and differences in the implementation methodologies among three major classification societies were concluded, including China, the United States, and Norway. The specific applications and research hotspots of FMEA/FMECA in the fields of modern ships and marine equipment were further elaborated. The existing difficulties and challenges in the application of FMEA/FMECA were also pointed out. The future development trends of FMEA/FMECA were predicted. Research results indicate that this methodology has been widely applied to the failure and risk assessment of ship power systems, electrical and automation systems, critical hydraulic and piping systems, and various types of marine engineering equipment. Research hotspots focus on how to improve the accuracy and objectivity of FMEA/FMECA, particularly by integrating it with the analytic hierarchy process to scientifically determine the weights of parameters within the risk priority number (RPN), using fuzzy set theory to handle uncertainty and subjectivity in the assessment process, and employing deep learning and big data technologies to dynamically predict real-time failure modes. The difficulties and challenges primarily include insufficient analytical capability for complex integrated systems, a lack of high-quality failure data, and the limitations of traditional RPN calculation methods. FMEA will embrace a more intelligent, systematic, and full life cycle-oriented evolution. The first is data-driven intelligent analysis, which involves using digital twin and artificial intelligence technologies to transition from static assessment to dynamic prediction and predictive health management. The second is the adaptive expansion to address new types of risks, so as to address the novel challenges posed by intelligent autonomous ships and green new-energy vessels. Ultimately, FMEA will be deeply integrated into the full life cycle of ships, from design and operation to maintenance, forming an ever-optimizing closed-loop risk management system.More>
2026, 26(1): 158-175. doi: 10.19818/j.cnki.1671-1637.2026.057
Research review on dynamics and fault diagnosis of railway vehicle gearboxes
CHEN Yue-jian, LI Yi-fan, LING Liang, LIU Jian-xin, JIN Si-qin, ZHOU Kai
Abstract: The research progress on dynamic modeling and response characteristics analysis of railway vehicle gearboxes was reviewed from two aspects: the dynamic research under internal and external excitation, and the dynamic research under fault conditions. The advantages and disadvantages of different models were summarized in terms of the research object, consideration factors, and coupling complexity. The influence of different fault types on the dynamic characteristics of gearboxes was concluded. The application of signal processing methods and artificial intelligence technologies in the fault diagnosis of railway vehicle gearbox was systematically elaborated. The characteristics and shortcomings of the existing methods were also discussed. The results show that the dynamic modeling and characteristic research of railway vehicle gearboxes should fully consider the unique working environment and structural characteristics of gearboxes, focus on developing high-precision rigid-flexible coupling multi-body dynamic models, and strengthen the modeling and experimental verification of multi-physics field coupling, thus providing more reliable theoretical support for fault feature extraction and health status assessment. In addition, the research on the fault evolution mechanism of typical fault modes should be enhanced. The methods including hybrid modeling and digital twin should be combined to conduct composite fault scenario simulation and full-life simulation analysis, offering a theoretical basis for the fault prediction and health management of railway vehicle gearboxes. Finally, more advanced fault diagnosis technologies should be developed with actual train data to verify the effectiveness of the diagnostic methods, so as to meet the high precision and real-time requirements of railway vehicle fault diagnosis, and promote the theoretical and practical progress of health management and operation decision-making throughout the entire life cycle of railway vehicle gearboxes.More>
2026, 26(1): 176-199. doi: 10.19818/j.cnki.1671-1637.2026.058
Transportation Infrastructure Engineering
Moisture migration in frozen silt under different moisture content and negative temperature gradient
GAO Feng, CHEN Zhi-de, ZHANG Jun-hui, ZHENG Jian-long, SHENG Dai-chao
Abstract: To investigate the effects of initial moisture content and negative temperature gradient on water migration during the freezing process of silt, five numerical experiments under undrained conditions were conducted using the simulation software COMSOL Multiphysics 6.0. The study focused on analyzing the dynamic response of freezing depth development, temperature field evolution, unfrozen water distribution, water migration flux, and frost heave deformation throughout the freezing process. This analysis revealed the combined influence of the two factors on the water migration mechanism. The results show that the freezing process of silt exhibits distinct stages, characterized by a rapid initial increase in freezing depth followed by a gradual stabilization. The negative temperature gradient plays a significant regulatory role in the freezing process. Increasing the negative temperature gradient notably accelerates the advancement of the freezing front and leads to a substantial increase in the final stabilized maximum freezing depth. When the negative temperature gradient rises from 12.5 ℃·m-1 to 22.5 ℃·m-1, the maximum freezing depth increases by approximately 63%. The vertical distribution of moisture content changes significantly before and after freezing. Higher initial moisture content and a steeper negative temperature gradient induce more pronounced water migration in the unfrozen zone, with the peak moisture content shifting downward as the negative temperature gradient increases. In the early freezing stage, continuous water supply from the underlying unfrozen zone to the freezing front is the primary cause of rapid frost heave. As freezing progresses, the water migration flux gradually weakens due to the stabilization of the temperature field and the reduction in unfrozen water content. Consequently, the rate of frost heave development decreases, eventually reaching a relatively stable magnitude. Based on the moisture migration characteristics of frozen silt identified in this study and considering the potential limitations of current drainage measures on the Gongyu Expressway, the importance of blocking upward water migration within the subgrade for deformation control is further emphasized.More>
2026, 26(1): 200-210. doi: 10.19818/j.cnki.1671-1637.2026.051
Analysis of thermal characteristics and thermal accumulation effect of integrated rigid pile-raft subgrade applied in the permafrost region of Qinghai-Xizang Plateau
QUAN Lei, GUAN Xin, TIAN Bo, LI Li-hui, LI Si-li, ZHANG Pan-pan, HE Zhe
Abstract: To verify the applicability of the integrated rigid pile-raft subgrade (PRS) in permafrost regions of the Qinghai-Xizang Plateau and to clarify its thermal characteristics and thermal disturbance effects on the permafrost foundation, temperature field data during the construction and the first year after completion of the first highway PRS test section in the permafrost region were monitored, and comparative analyses were conducted with adjacent block-stone subgrade (BSS) and natural ground (NG). Research results show that the seasonal freeze-thaw depths of the upstream borehole without water, the midstream borehole with less-water, and the downstream borehole with more water in the PRS are 6.8, 10.3, and 8.5 m, respectively. The seasonal freeze depths of the BSS is 6.7 m, and that of the NG is 2.9 m. A non-freezing interlayer is formed in the midstream borehole of the PRS within the depth range of 3.80–8.25 m. The monthly average temperature-depth curve clusters of the PRS present an obvious right-skewed distribution, which is manifested by a longer duration and greater depth of positive temperatures. The BSS shows a similar but weaker trend, while the temperature distribution of the NG is approximately symmetrical around 0 ℃. The heat conduction capacity, heat storage capacity, and cold conduction capacity of the PRS are higher than those of the semi-rigid base asphalt pavement combined with BSS. A significant thermal accumulation effect is exhibited by the PRS, followed by the BSS, while the natural ground shows an approximately balanced thermal state. The thermal accumulation effect of the midstream borehole of the PRS is significantly higher than that of other boreholes due to the scale effect formed by the continuous pile-raft structure. Within one annual cycle, the cumulative heat inflow at the bottom surface of the raft reaches 139.2 MJ·m-2. Strong fluctuations of the annual cumulative heat in shallow foundation layers are related to the combined effects of water content variation and freezetthaw phase change in the seasonal freeze-thaw layer, while fluctuations in deep foundation layers are related to heat transfer driven by groundwater flow. It is suggested that thermal insulation materials be installed between the raft and the subgrade fill to mitigate heat inflow and protect the underlying permafrost. The analysis results provide a reference for structural optimization and engineering applications of the integrated rigid PRS in the permafrost region of the Qinghai-Xizang Plateau.More>
2026, 26(1): 211-223. doi: 10.19818/j.cnki.1671-1637.2026.005
Model tests on temperature field and heat exchange efficiency of energy pile in loess foundation
CAO Wei-ping, ZHANG Zuo-peng, HE Zhan-peng, LUO Long-ping, LI Qing, KONG Gang-qiang
Abstract: Model tests on energy piles in loess with different saturation degrees under summer/winter mode were conducted to understand the heat exchange efficiency characteristics. Remolded loess was used with saturation degrees of 42% and 69%, respectively. The precast reinforced concrete piles were applied as the model energy pile, with diameters of 50, 65, and 80 mm, installed with U-shaped and W-shaped heat exchangers. The energy piles were placed in the loess using two methods: embedded/static jacking. The experimental results show that the temperature field in surrounding soils exhibits obvious three-dimensional characteristics, and the heat exchange between the pile and soil is mainly in the horizontal direction. The horizontal influence zone of the energy pile temperature is not less than 3 times the pile diameter. The temperature gradient in surrounding soils is closely related to the saturation degree of loess, operating mode, soil displacement effect during construction, and heat exchanger type. Overall, the heat exchange efficiency in summer mode is lower than that in winter mode. A higher saturation degree for loess corresponds to a higher heat exchange efficiency in summer mode, while the truth is the opposite in winter mode. Either in the winter or summer mode, when the loess saturation degree is the same, the heat exchange efficiency of embedded piles with W-shaped heat exchanger in loess is higher than that of jacked piles with U-shaped heat exchanger, while the heat exchange efficiency of embedded piles with U-shaped heat exchanger is the lowest. The heat exchange efficiency of energy piles with diameters of 50 and 65 mm is nearly the same, while that of 80 mm diameter ones is much lower. Compared with non-displacement piles, the displacement piles can improve the heat exchange efficiency by around 13.7% averagely.More>
2026, 26(1): 224-235. doi: 10.19818/j.cnki.1671-1637.2026.097
Integrated track-bridge management method for large-span railway suspension bridges based on train operation performance
LI Xiao-zhen, CHENG Yi-fan, WEN Chen, WANG Ming, CHEN Rong, WANG Ping
Abstract: A management methodology and indicator system are expected to be established for track geometry on large-span suspension bridges to address the shortcomings of existing track management criteria in bridge and track maintenance. Taking a suspension bridge with a main span of 1 092 m as the research object, a vehicle-track-bridge coupled dynamic analysis was conducted to investigate the influence rule of bridge deformation-induced track geometry evolution on the operation of high-speed trains on the bridge. The cutoff wavelength for smoothness management of track geometry was also identified. Based on a wavelength separation approach, the track irregularities were distinguished from the dynamic longitudinal profile of the bridge. A unified indicator system applicable to large-span suspension bridge scenarios was proposed in reference to the management standards of conventional railway lines. Furthermore, a quantitative analysis was performed to evaluate the contributions of different track geometry components to car body acceleration. Research results show that a cutoff wavelength of 120 m can be adopted for track smoothness management on long-span bridges. Based on this cutoff wavelength, an effective separation between track irregularities and the dynamic longitudinal bridge profile can be achieved, enabling the track management indicators for large-span suspension bridges to be unified with those of conventional railway lines. According to ride comfort limits, the management thresholds for track irregularities and bridge longitudinal profiles can be determined. An integrated track-bridge management framework can thus be established for large-span railway suspension bridges, providing guidance for their design and operation.More>
2026, 26(1): 236-246. doi: 10.19818/j.cnki.1671-1637.2026.006
Calculation method for ultimate support force of shield tunnel in homogeneous unsaturated clay strata
WANG Dao-yuan, ZHANG Gao-xiang, HE Shao-hui, WU Wei, CHEN Yu-bo, LIU Cheng-hong, MA Ji-wen, SONG Bao-lu, YUAN Jin-xiu, LIU Yong
Abstract: To accurately determine the ultimate support force of shield tunnels in unsaturated clay strata, a systematic study was conducted on the calculation method of support force at the excavation face of shield tunnels in homogeneous unsaturated clay strata by combining theoretical derivation and engineering case analysis. By considering the non-vertical slip surface morphology of the strata, the effect of soil matrix suction, the incomplete soil arching effect, and the characteristics of principal stress deflection, an analytical model of vertical earth pressure considering multi-factor coupling was constructed. Based on the limit equilibrium wedge model, a calculation method for the support force at the excavation face was further derived and constructed. The influence of key parameters on support force was discussed through engineering examples. The results indicate that the soil arching effect triggers a nonlinear evolution of vertical stress in the soil, showing a steep increase followed by a slower growth rate with increasing burial depth. The vertical stress at the top of the tunnel is positively correlated with the angle and saturation of the sliding surface and negatively correlated with the cohesive force and arch displacement. Under high saturation conditions, the recommended calculation method has a high degree of consistency with the standard calculation results, and both results are significantly higher than the predicted values of Terzaghi's theory, with a deviation range of up to 50%. As the saturation decreases, the recommended solution gradually approaches Terzaghi's theoretical solution, and the fluctuation amplitude of loose soil pressure caused by changes in saturation can reach 30%. The ultimate support force at the excavation face is influenced by the coupling of multiple parameters such as internal friction angle, cohesive force, and saturation. Among them, the saturation of the strata is the key controlling factor, and its difference can lead to a change in the support force value of more than 50%.More>
2026, 26(1): 247-256. doi: 10.19818/j.cnki.1671-1637.2026.052