30 September 2026, Volume 39 Issue 9
    

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    Special Column on Intelligent Testing Technologies for Subgrade Engineering
  • LIU Lu-lu, TIAN Hong-liang, CAI Guo-jun, ZHANG Jun-hui, ZHENG Jun-jie, LIU Song-yu, HUI Ying-xin
    China Journal of Highway and Transport. 2026, 39(9): 1-22. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.001
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    As a core load-bearing unit of transportation infrastructure, the accurate identification of subgrade stratigraphic structures and foundation characteristics is critical for ensuring engineering safety and durability. However, with expanding construction scales, the limitations of traditional investigation methods in data processing efficiency, complex geological interpretation, and dynamic response have become increasingly prominent, driving the industry toward an intelligent transformation. In recent years, the integration of Artificial Intelligence (AI) with emerging technologies such as optical fiber sensing, UAV LiDAR, and remote sensing has significantly enhanced the precision of wide-area deformation monitoring and risk identification, effectively extending technical boundaries. Although most current achievements remain in the experimental validation stage and lack systematic engineering solutions, future research focusing on advanced algorithms-including multi-source information fusion, knowledge graphs, and transfer learning-to construct standardized intelligent evaluation systems will be the primary path to achieving large-scale application and refined management in subgrade investigation. Specifically, the development of digital twin systems through the deep integration of physical mechanisms and data-driven algorithms will drive a paradigm shift from “passive geological description” to “active performance evolution prediction,” ushering in a new model of intelligent management throughout the subgrade life cycle. On this basis, this paper reviews the research progress and application trends of AI in subgrade engineering investigation. By revisiting the development of traditional techniques and analyzing the bottlenecks of drilling and in-situ testing, it highlights the advantages of machine learning in stratigraphic identification, parameter prediction, and geological classification. Furthermore, the practical performance of AI in intelligent geological information extraction, automated data modeling, and subsurface anomaly identification is summarized to explore its potential value in enhancing investigation efficiency. Combined with the synergistic evolution of intelligent hardware and algorithms, this study aims to delineate the key technologies empowering subgrade investigation, providing insights for establishing high-efficiency, intelligent, and refined investigation systems.
  • LIN Kai, ZHANG Dan, WU Lan, HAN Xin, LIU Xiao-qing, ZHU Bao-kun
    China Journal of Highway and Transport. 2026, 39(9): 23-33. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.002
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    Precise monitoring of subsurface structures along expressways is vital for ensuring subgrade stability, identifying geological anomalies, and preventing diseases. This study relied on the coexisting telecommunication fiber optic cables along the Maoshan-Tianwang section of the Hu-Ning Expressway and integrated distributed acoustic sensing (DAS) to explore the potential of ambient noise tomography for high-resolution shallow subsurface imaging under complex highway conditions. The aim was to provide an innovative technical approach for the long-term monitoring and dynamic assessment of subgrade health status. The research analyzed typical waveform plots and power spectral density (PSD) to reveal the noise characteristic differences among elevated bridge, mountain-penetrating tunnel, and regular subgrade sections. This analysis offered a scientific basis for subsequent signal selection and data processing. Ambient noise tomography used surface waves excited by vehicles as the noise source. The study applied the three-station interferometry method to optimize the noise cross-correlation function (NCF). It generated dispersion energy images based on multichannel analysis of surface waves (MASW) and inverted the S-wave velocity structure using competitive particle swarm optimization algorithm. The results showed that the two-dimensional velocity profile, covering traces 2 700 to 3 800 over a 2 km interval and an 80 m depth range, clearly delineated the layered features of the subgrade, clay layer, and underlying Cretaceous Gecun Formation siltstone. The profile revealed the relationship between velocity variations and terrain morphology along the route. The overall findings aligned highly with regional geological data. Near trace 3 420, the study observed time delay in the NCF and low-velocity anomalies in the velocity profile. These features corresponded to the location of a traffic culvert beneath the fiber optic cable, verifying the feasibility of detecting underground voids. The research concludes that DAS combined with ambient noise tomography effectively utilizes coexisting telecommunication fiber optic cable resources. It achieves low-cost, efficient imaging of shallow subsurface structures and anomalies. This approach provides intelligent monitoring solutions for subgrade stability assessment and green disease prevention.
  • WANG Jun, ZHANG Kang-shuai, LIU Zhi-ming, FU Hong-tao
    China Journal of Highway and Transport. 2026, 39(9): 34-46. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.003
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    This study aims to address the severe threat posed to public safety by the concealed and sudden nature of subgrade collapses, as well as the challenge of achieving long-distance, distributed, and low-cost monitoring. In recent years, flexible piezoelectric sensing technology has increasingly been applied within the field of geotechnical engineering monitoring. Against this backdrop, this study employs a sensor-enabled piezoelectric geocable (SPGC) as the monitoring sensor. Based on the piezoelectric effect and impedance strain effect, this cable can effectively detect internal soil deformation and convert it into electrical signal output. Through field trials, the accuracy of fixed-point SPGC in determining different collapse locations was investigated, whilst analysing internal soil deformation characteristics. The test model, with a total length of 10 m, deployed SPGC and densely distributed fibre optic monitoring networks at burial depths of 0.2 m, 0.4 m, and 0.6 m. Each layer featured five monitoring units spaced 2 m apart. An inflatable bladder simulated the collapse process of the left, central, and right sections of the roadbed. Data acquisition employed an impedance analyser and cabinet-type optical fibre demodulator. Results demonstrated that both SPGC and dense distributed fibre networks accurately captured strain responses. At varying burial depths, SPGC exhibited certain stability advantages over dense distributed fibre networks: When burial depth decreased from 0.6 m to 0.4 m, the maximum microstrain recorded by the dense distributed fibre network sharply declined and misidentified the collapse location. In contrast, SPGC exhibited only a slight decrease in normalised impedance and accurately pinpointed the collapse location.This study provides preliminary validation of the feasibility of SPGC for monitoring subgrade subsidence. By continuously sensing variations in SPGC impedance signals, the technology monitors deformation and strain distribution within subgrade soil, thereby enabling early identification and localisation of potential subsidence risks. This offers valuable insights for establishing an intelligent monitoring system covering the entire disaster lifecycle.
  • DONG Shi, TIAN Shu-ming, LONG Zhi-you, LIU Xiao-yang, WANG Hai-nian
    China Journal of Highway and Transport. 2026, 39(9): 47-61. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.004
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    Accurate and reliable monitoring data provide important support for risk assessment and safety warning of highway slopes. A two-stage blind calibration method was proposed based on time-frequency deep learning to address sensor signal faults in highway slope monitoring. These faults are caused by the coupling of multiple factors, such as environmental disturbances and equipment failures. In the first stage, a fused architecture integrating Temporal Convolutional Network (TCN), SincNet, and Transformer was constructed for signal status classification and diagnosis. Consequently, efficient identification of five signal states was achieved. In the second stage, an autoencoder network incorporating an attention mechanism was designed. Notably, blind calibration for different identified fault signal types was performed without external references. Test studies were carried out relying on GPS-RTK field data collected from the Baihe slope of the Shiyan-Tianshui Expressway in Shaanxi Province. The experimental results indicated that the average accuracy of the diagnostic model was 96.8% in identifying the five signal states. Thus, excellent classification performance was demonstrated. During the signal calibration phase, the Mean Absolute Error (MAE) values for the calibration model incorporating an autoencoder were 0.000 46 m, 0.000 47 m, and 0.000 61 m, respectively, with a Root Mean Square Error (RMSE) within 0.000 71 m. These results effectively restored the true trend of the data. Additionally, the memory usage of the model was merely 40.84 MB with a single inference time of 5.98 ms. Therefore, the requirements of edge devices were met in highway slope monitoring for lightweight and real-time computing. Finally, the model performance was discussed thoroughly through robustness and generalization tests under different parameters, disturbance levels, and datasets. The accuracy and stability of the model were verified based on the analysis under various working conditions. In conclusion, reliable technical support is provided by this study for anomaly processing and data enhancement of sensor monitoring signals in highway engineering under complex environments.
  • CAO Zi-jun, CHEN Xing-zhou, LIU Tao, CAI Guo-jun, WANG Xuan-hao
    China Journal of Highway and Transport. 2026, 39(9): 62-76. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.005
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    Reconstruction of the geological strata is crucial for subgrade engineering design and construction safety. In recent years, Markov Random Field (MRF) strata modeling method, which is based on borehole data, has received extensive attention. To address the issues of low efficiency and insufficient characterization of local strata variation in long-section MRF geological modeling, this paper proposed a Double-Loop Cross-Validation (DLCV) intelligent learning and Group-Wise Strategy (GWS) method for MRF geological model based on the Location Information Matrix (LIM). The proposed method established a MRF geological model based on the LIM, which explicitly represented the spatial constraint strength of surveyed points on predicted points to regulate the MRF state update process. Besides, a MRF neighborhood selection framework based on the DLCV was constructed. This framework quantitatively evaluated the modeling performance of different neighborhood systems to achieve data-driven selection of the neighborhood system, and Particle Swarm Optimization (PSO) algorithm was integrated to improve the efficiency of MRF model parameter learning. Subsequently, an efficient GWS method was introduced to divide the modeling area into several sections based on the number of boreholes. Within each section, neighborhood selection, parameter learning, and strata simulation were carried out independently to realize fine strata modeling in local areas. Finally, information entropy was used to quantify the uncertainty of strata modeling results. Verification through virtual and real-life cases showed that the proposed method overcame the problem that the neighborhood system selection relied on subjective experience, significantly improved the efficiency of long-section strata modeling, and enhanced the accuracy of local strata structure modeling.
  • WANG Cai-jin, ZHU Shuai, CAI Guo-jun, XIE Liang-fu, LIU Xue-jun, LI Yan-jun, LIU Song-yu
    China Journal of Highway and Transport. 2026, 39(9): 77-89. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.006
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    With the advancement of infrastructure expansion and reconstruction projects, the problem of differential settlement between new and old subgrades has become a critical challenge that restricts engineering safety and service performance. Traditional borehole sampling methods are limited by soil disturbance and anisotropy, making it difficult to accurately characterize the spatial variability of soil properties, while existing numerical simulations and empirical formulas are constrained by idealized assumptions or parameter uncertainties and cannot effectively quantify non-stationary variation patterns under complex geological conditions. To address the significant differential settlement and the difficulty of accurately characterizing soil parameter variability in soft soil areas during highway expansion projects, this study takes the Huai'an-Jiangdu section of the Beijing-Shanghai Expressway as the research background. Based on piezocone penetration test (CPTU) data, a two-dimensional soil parameter field reconstruction method is proposed by integrating Bayesian compressed sensing (BCS) with the discrete cosine transform (DCT), enabling the reconstruction of cone tip resistance (qt) and sleeve friction (fs). The reconstructed results show low uncertainty, and autocorrelation function (ACF) analysis quantitatively reveals significant anisotropy of soil parameters in both horizontal and vertical directions. The results indicate that the reconstructed qt of the old subgrade ranges from 0 to 5.0 MPa, while that of the new subgrade ranges from 0 to 8.0 MPa; the reconstructed fs of the old subgrade ranges from 0 to 300 kPa, while that of the new subgrade ranges from 0 to 170 kPa. In the new subgrade, the high-value zones of overconsolidation ratio (OCR), undrained shear strength (Su), and compression modulus (Es) are thicker and more continuous, with peak values reaching 30, 300 kPa, and 35 MPa, respectively. In contrast, the old subgrade exhibits weaker high-value zones, with Su mainly concentrated in the 140 to 190 kPa range and Es in the 12 to 22 MPa range, showing significant attenuation along the alignment. This study provides a data-driven and physically interpretable method for soil parameter field reconstruction and analysis, offering strong support for the prediction of differential settlement and the long-term performance evaluation of soft soil subgrade.
  • LIU Xiao-yan, CAI Guo-jun, LIU Song-yu, GENG Xue-yu, ZHENG Ya-lan, XIANG Guo-sheng, LIU Lu-lu, WEI Jia-chen
    China Journal of Highway and Transport. 2026, 39(9): 90-104. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.007
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    To address the active temperature control needs for frost heave prevention in cold-region subgrades, this study systematically investigates the thermal response patterns and heat transfer mechanisms of an energy pile-soil system under active temperature control through a combination of laboratory model tests and numerical simulation. A temperature monitoring system with 144 measurement points was established, and 48-hour thermal response tests were conducted under three inlet temperature conditions: 25 ℃, 30 ℃, and 35 ℃. The test process was simulated and validated using COMSOL finite element analysis software. The results indicate that: ① The temperature field exhibited a distinct three-stage temporal evolution, namely rapid rise-gradual slowdown-quasi-steady state, and showed an exponential radial attenuation pattern together with a longitudinally non-uniform distribution characterized by higher temperatures in the middle and lower temperatures at both ends. Specifically, based on the results of the 48 h laboratory model test, the effective thermal influence radius was approximately 150 mm; based on the 720 h long-term prediction obtained from the experimentally validated numerical model, the effective thermal influence radius could further expand to 300 mm. ② Solid heat conduction dominates the system's heat transfer mechanism, with the temperature field showing symmetrical distribution in cross-section (average temperature difference ≤ 0.5 ℃), indicating negligible influence from fluid flow in the U-shaped pipes. ③ The mechanisms of inlet temperature and fluid velocity are distinct: inlet temperature acts as a thermodynamic control parameter, showing a linear positive correlation with steady-state temperature rise (The temperature rise increases by approximately 7%-8% for every 5 ℃ increase in temperature); fluid velocity primarily regulates transient response, with increased velocity shortening the time to reach steady state by about 35%, while having a minimal effect on long-term steady state (<0.5 ℃). This study reveals the key control mechanisms of the heat transfer process in actively controlled energy piles, providing a theoretical basis for their optimized design and operational control in cold-region subgrade engineering.
  • YAN Han, LÜ Li-bo, XIE Zhi, TENG Ji-dong, SHAN Feng, GUAN Wei, WU Hong-gang
    China Journal of Highway and Transport. 2026, 39(9): 105-116. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.008
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    Traditional subgrade evaluations, constrained by static or quasi-static metrics, often fail to capture the true response under dynamic loading. Based on a representative section of the Nanning-Zhanjiang Expressway, this study proposes an in-situ dynamic testing approach employing pavement-mounted sensors. By applying controlled sinusoidal sweep excitations, the dynamic characteristics of the entire subgrade system were inferred from surface response data. Further a comparative analysis between cement-treated and untreated red clay subgrades is conducted, focusing on key dynamic features: resonant frequencies, attenuation coefficients, and lateral coherence. Results show that cement treatment increases the natural frequency by approximately 16% while maintaining a consistent frequency ratio, signifying a uniform enhancement in overall stiffness. The treated subgrade exhibits synergistic dynamic behavior with high coherence and stable attenuation, reflecting concurrent improvements in structural integrity and damping capacity. Furthermore, the defined “dynamic stiffness ratio” not only quantifies the stiffness enhancement but also identifies system resonance via its distinct valley. The findings validate that the geometric features of phase trajectories accurately map nonlinear stiffness evolution and energy dissipation in subgrade systems. This transformation of complex response data into intuitive graphical signatures provides a physically interpretable and highly sensitive method for evaluating the structural integrity of special soil subgrades.
  • WU Yang, LIN Jia-jie, LI Wei-shen, LIN Luo-yi, WU Yi-hang, WEN Li-wei, CUI Jie
    China Journal of Highway and Transport. 2026, 39(9): 117-127. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.009
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    With the development of the South China Sea reef project, transportation infrastructure such as roads and airport runways have been successively built on these reef foundations. The reef coral sand shows the characteristics of mixed grain composition and wide gradation, where coral sand and large-sized coral gravel are commonly found in a mixed and combined state. Coral sand-gravel mixtures are commonly directly used as subgrade materials in island-reef engineering. Under long-term cyclic loading, the dynamic response of coral sand-gravel mixture is influenced by multiple factors. This study investigates the dynamic characteristics of coral sand-gravel mixtures under long-term cyclic loading through a series of large-scale cyclic triaxial tests under drained conditions with multi-stage loading, considering different cyclic deviator stresses, effective confining pressures, and gravel contents. The test results show that the axial strain of coral sand-gravel mixtures increases with higher cyclic deviator stress, but decreases with greater gravel content and effective confining pressure. This is primarily attributed to the enhanced confinement of particle movement by increased effective confining pressure, while increased gravel content alters the skeletal structure of the mixture, the skeleton structure dominated by coral sand-gravel mixture has higher strength. The accumulation rate of axial strain decreases as the number of loading cycles increases. Furthermore, cyclic deviator stress significantly enhances both the energy dissipation and damping ratio of the coral sand-gravel mixtures, whereas the effect of effective confining pressure on them is opposite. The findings of this study provide an important theoretical reference for assessing the long-term stability of coral sand-gravel mixture subgrades on island reefs.
  • QIAN Jin-song, GOU Yong-tao, TANG Jia-qi, JIANG Zhong-kai
    China Journal of Highway and Transport. 2026, 39(9): 128-139. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.010
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    Pavement performance is significantly affected by the change of water content and compaction degree in the loess subgrade in service. To overcome the insufficiency of the inversion accuracy by the single physical field detection, resulting from the coupling interference of moisture content and compaction degree, this study analyzed the response characteristics of resistivity and Rayleigh wave velocity of compacted loess to water content and compaction degree. Four machine learning models were compared in terms of their performance in joint wave-electric inversion. Based on this comparison, a joint wave-electric nondestructive testing method combining Bayesian optimization (BO) and extreme gradient boosting (XGBoost) was proposed. Lastly, the engineering applicability was verified by practical application. The results show that the resistivity of compacted loess is more sensitive to the change of water content (correlation coefficient is -0.874), and the Rayleigh wave velocity is mainly controlled by the compaction degree (correlation coefficient is 0.891), but both of them show a good power function relationship with water content and compaction degree (R2≥0.93). BO-XGBoost has the best inversion performance among the four machine learning models without the systematic error in the single physical field method, the average relative error of water content and the compaction degree is reduced by 10.95% and 2.92% respectively. The application proves that the proposed method can effectively identify the high moisture content or insufficient compaction state in the wave-electric anomaly area, and provide support for the evaluation and treatment of the loess subgrade.
  • Special Column on Operation Safety Assurance Technologies for Intelligent Electric Vehicles
  • WANG Shu, LI Ya-jin, ZHAO Xuan, TIAN Jia
    China Journal of Highway and Transport. 2026, 39(9): 140-153. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.011
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    Lane-changing trajectory planning for intelligent vehicles is one of the key research directions of autonomous driving technology and an important prerequisite for ensuring vehicle driving safety. To make lane-changing trajectories adapt to dynamic driving environments and conform to the lane-changing habits of real drivers, this paper proposed a human-like lane-changing trajectory planning method integrated with predicted trajectories. Firstly, an expert lane-changing trajectory set and a candidate trajectory set for model training and validation were constructed based on naturalistic driving datasets. Secondly, to obtain the reward mechanism of real drivers during lane changing, a human-like lane-changing reward function was established via Inverse Reinforcement Learning (IRL). A deep neural network was adopted to replace the linear function used in traditional IRL, which improved the learning ability of the model. Finally, an optimization objective function and corresponding constraints were designed by comprehensively taking the human-likeness, comfort, efficiency and safety of lane-changing trajectories into account to adapt to dynamic driving environments. The reference trajectory was optimized in both spatial and temporal dimensions using piecewise polynomials and nonlinear programming, which realized safe and human-like lane-changing trajectory planning. To fully reflect the future evolution of driving environments, vehicle predicted trajectories were introduced and integrated into the construction of candidate trajectory sets, trajectory feature vectors and objective functions, effectively enhancing the overall performance of the model. A replay simulation environment was established based on real lane-changing trajectory data to verify the effectiveness and generalization ability of the proposed method. Simulation results show that the proposed method can generate safe and reasonable lane-changing trajectories in various scenarios, and the planned trajectories have high similarity with real ones. Compared with the traditional nonlinear programming method, the human-likeness of generated trajectories is significantly improved. This method provides an effective solution to the human-like lane-changing trajectory planning of intelligent vehicles.
  • LIN Fen, SUN Jia-zuo, LIN Kai-hong, LU Xin-yue
    China Journal of Highway and Transport. 2026, 39(9): 154-164. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.012
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    To enhance the lateral stability of distributed electric drive vehicles on low-friction coefficient roads and under system uncertainties, a hierarchical direct yaw moment control strategy integrating an Extended State Observer (ESO) and an Improved Non-singular Fast Terminal Sliding Mode Control (INSFTSMC) was proposed. First, a lateral dynamics model of the vehicle was established to derive the desired yaw rate and the desired sideslip angle. For the upper-level controller, to address the chattering problem inherent in traditional sliding mode control, a new sliding mode approach law combining a variable-speed reaching law and an exponential reaching law was introduced. When far from the sliding surface, the system rapidly approached the sliding surface, and when near the sliding surface, the exponential reaching law dominated, allowing the approach speed to decrease smoothly and avoiding unnecessary high-frequency switching. Furthermore, considering the impact of external disturbances on the control system, the ESO-INSFTSMC control strategy was designed. Through the ESO, disturbances were expanded into a third system state, enabling real-time observation and compensation for unmodeled dynamics and unknown external disturbances of the system. The lower-level controller allocated torque to the four wheels with the objective of minimizing the sum of squares of the tire load rates, subject to tire friction constraints. Finally, a MATLAB/Simulink-Carsim co-simulation platform was established, and the proposed control strategy was validated under three operating conditions: single-cycle sinusoidal steering, continuous sinusoidal steering, and crosswind disturbance. Simulation results indicate that, compared with traditional sliding mode control (SMC), the ESO-INSFTSMC method reduces the maximum yaw rate errors by 54%, 57.4%, and 61.6%, and the maximum sideslip angle errors by 37.3%, 31.2%, and 44.6%, under the respective test conditions, This indicates a significant improvement in vehicle lateral stability.
  • ZHENG Guo-feng, YANG Si-yu, LI Shi-ying, ZHAO Shu-en, WEI Han-bing
    China Journal of Highway and Transport. 2026, 39(9): 165-179. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.013
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    Under complex road conditions, the control strategies of traditional suspensions often suffered from insufficient vibration-reduction performance and delayed height adjustment due to the difficulty in accurately matching road surface characteristics. To address this problem, this paper proposed an adaptive control strategy for electronically controlled air suspension (ECAS) integrated with Random Forest-based road surface recognition, aiming to improve system adaptability under complex operating conditions. First, a Random Forest road surface grade recognition model was constructed, and a Bayesian optimization algorithm was used for iterative hyperparameter tuning to determine key model parameters such as the optimal number of decision trees, maximum depth, and number of splitting features. This enabled fast and accurate classification of typical A-D grade road surfaces and provided real-time road condition support for subsequent control decisions. Second, for suspension damping force adjustment, an adaptive skyhook-acceleration damping control strategy was designed, which dynamically adjusted damping parameters based on real-time road surface recognition results. Meanwhile, a particle swarm optimization (PSO) algorithm was introduced to achieve multi-objective collaborative optimization of ride comfort indicators, safety indicators, and mechanical constraints, determining the optimal damping parameter adjustment interval. Finally, to address body attitude deviation caused by load variation and road disturbances, an SM-PID-based air spring height control algorithm was proposed. By leveraging the strong robustness of sliding mode control to suppress external disturbances and combining the high-precision regulation characteristics of PID, accurate tracking control of air spring height was achieved, ensuring the stability of suspension geometric parameters. The performance of the proposed control strategy was verified on A-D grade typical road surfaces through Carsim/Simulink co-simulation and Hardware-in-the-Loop (HIL) testing. The results showed that the Random Forest road surface recognition model achieved high-precision road grade classification; the adaptive skyhook-acceleration damping control strategy significantly improved body acceleration response, with vibration-reduction performance superior to improved skyhook control and other comparative algorithms; and the HIL test results were highly consistent with the simulation conclusions, verifying the consistency and reliability of the proposed strategy.
  • XIA Xu, REN Guo-quan, WANG Rui-xuan, ZHU Yan, SONG Shi-lu, LI Jun
    China Journal of Highway and Transport. 2026, 39(9): 180-192. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.014
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    To address the driving anti-slip problem of distributed electric drive vehicles on unknown and complex road surfaces, an integrated control framework fusing real-time road identification, optimal slip ratio tracking, and torque coordination redistribution was proposed. First, the optimal slip ratio and maximum adhesion coefficient were identified online through a double-layer screening algorithm based on the Burckhardt model. Subsequently, a composite controller combining Sliding Mode Control (SMC) and Proportional-Integral-Derivative (PID) control was designed for optimal slip ratio tracking by introducing a slip ratio error function. Fur-thermore, a torque redistribution strategy with slip correction was proposed based on the concept of “slip stability margin” to improve vehicle dynamics on asymmetric road surfaces. Finally, experimental verifications were conducted on low-adhesion, Joint, Split-μ, and coupled complex road surfaces using a co-simulation platform of MATLAB/Simulink and CarSim. The simulation results indicate that the proposed identification method possesses higher accuracy and robustness compared to typical fuzzy road identification methods in existing literature under test conditions. The designed composite control system effectively intervenes when wheels enter the unstable slip region. It ensures the rapid and stable convergence of the slip ratio for each wheel. Consequently, the power performance and stability of the vehicle during driving on complex road conditions are significantly improved. The proposed method demonstrates good engineering application value.
  • GUO Jian-bao, FANG Bin, LIU Zhen-hai, LIU Li-ya, CAO Li-bo
    China Journal of Highway and Transport. 2026, 39(9): 193-204. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.015
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    With the continuous increase in the penetration rate of new energy vehicles domestically, incidents of fire and explosion after crashes have garnered growing attention. To effectively reduce the fire risk caused by short circuits due to crashes, this study, based on existing technical solutions, analyzes the power shutdown and discharge requirements after crashes and points out the shortcomings of current solutions in addressing instantaneous short circuits during crashes. Current regulations require that the high-voltage bus voltage be reduced to a safe threshold (below 30 V AC or 60 V DC) within 5 to 60 seconds after a crash. However, crash deformation is typically completed within 150 ms, and merely meeting regulatory requirements is insufficient to prevent fire and explosion during crashes. To address the above issues, this study proposes a strategy for ultra-fast shutdown and discharge. This strategy can achieve complete vehicle power shutdown within 2 ms after detecting a crash. Additionally, a dual-loop redundant power shutdown strategy combining Controller Area Network (CAN) lines and hardwired connections ensures reliable power shutdown even if a single loop has a short circuit or disconnection. After high-voltage shutdown, the Insulated Gate Bipolar Transistor (IGBT) discharge circuit is activated through a specific driving signal, enabling the discharge system to reduce the vehicle voltage to below 12 V within 18 ms. The discharge speed is approximately 2 000 times faster than the requirement of GB/T 31498, significantly enhancing the electrical safety of vehicles after crashes. The findings of this study provide an efficient strategy for ultra-fast power shutdown and discharge to enhance electrical safety protection in electric vehicles after crashes.
  • Bridge Engineering
  • LI Chuan-xi, ZHU Zi-jian, DENG Shuai, ZENG Zhen-hai, LI Hai-chun
    China Journal of Highway and Transport. 2026, 39(9): 205-216. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.016
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    The critical factor for enabling electrical deicing and snow melting in ultra-high performance concrete (UHPC) bridge decks or pavement layers lies in reducing electrical resistivity to acceptable levels while maintaining workability (slump flow) and mechanical properties. To address this challenge, we designed an orthogonal test incorporating three variables: millimeter-scale steel fibers (SSF), micrometer-scale carbon fibers (CF), and conductive nano carbon black (CNCB), each tested at three concentration levels. The experimental results quantified the effects of each variable on slump flow, compressive strength, tensile strength, and 28-day resistivity across the tested concentration ranges. An optimal hybrid for-mulation (2.0% volume fraction SSF, 0.8% volume fraction CF, 0.7% mass fraction CNCB) was identified, achieving balanced fluidity, mechanical performance, and reduced resistivity. Subsequent variable experiments introduced each conductive phase individually into UHPC at the optimized hybrid dosage. We systematically measured slump flow, mechanical strength, and age-dependent resistivity for both single-phase and hybrid UHPC systems. Correlation analyses elucidated the synergistic mechanisms governing workability-mechanical-conductivity balance in the ternary hybrid system. Electrical heating validation tests demonstrated the hybrid UHPC's engineering efficacy, with a 54.9 ℃ temperature rise after 150 minutes of electrification. The optimized hybrid UHPC formulation (2.0% volume fraction SSF, 0.8% volume fraction CF, 0.7% mass fraction CNCB) demonstrates concurrent optimization of workability, mechanical properties, and electrical conductivity. All conductive phases negatively impact UHPC workability, with cumulative effects in hybrid systems being sub-additive. SSF and CF enhance mechanical strength, whereas CNCB compromises it through matrix discontinuity. All phases reduce resistivity, particularly CF and CNCB which decrease it by 99.85% after 28 days. The hybrid system's resistivity reduction exceeds predictions from parallel resistance models, indicating synergistic size-effect-enhanced percolation networks. This indicates that the complementary size effects significantly enhance conductive network connectivity. At 28 days, the resistivity of the optimal hybrid UHPC decreases by 99.85% compared to plain UHPC. After 7 days, resistivity remains nearly unchanged. When electrified for 150 minutes, the temperature rises by 54.9 ℃, demonstrating strong potential for deicing and snow melting applications.
  • ZHAN Jia-wang, YANG Yun-ming, XU Xin-xiang, NI Zhen, JIA Ying
    China Journal of Highway and Transport. 2026, 39(9): 217-231. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.017
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    To address the difficulties in evaluating the working conditions of bearings in traditional highway prefabricated bridges, this paper proposes an online assessment method for bearing damage conditions based on vehicle-induced vibration responses. First, based on vehicle-bridge coupled vibration theory, acceleration responses from a limited number of measurement points under operational vehicle loads were acquired to establish a lightweight evaluation data foundation. Furthermore, a spectrum peak flexibility matrix diagonal matrix ratio index was constructed to achieve rapid localization and preliminary diagnosis of bearing damage. Finally, by integrating a simulated annealing algorithm to optimize the XGBoost model, quantitative evaluation of the extent of bearing damage was realized. Using a highway prefabricated simply-supported T-girder bridge as a case study, combined with theoretical analysis, numerical simulation, and field testing, the results demonstrate that the proposed index can accurately identify single and multiple bearing damages in prefabricated simply-supported girder bridges. It also exhibits strong robustness under varying vehicle types, speeds, road roughness levels, and noise interference. Moreover, the accuracy of damage severity assessment reached 97.08%, enabling precise identification of damage levels from minor to severe. A key advantage of this method is that it does not require prior knowledge of vehicle loads; only beam vibration response data are used to achieve rapid assessment of bridge bearing conditions. This provides effective support for lightweight monitoring and rapid inspection of highway prefabricated bridges.
  • SHU Jiang-peng, YU Hong-chuan, LI Xin-yang, XIA Ye, ZHANG Jin-yong, JIANG You, XU Sheng-liang
    China Journal of Highway and Transport. 2026, 39(9): 232-250. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.018
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    For the common data loss issue in structural health monitoring systems, a bridge vibration response reconstruction method based on the constrained denoising diffusion probabilistic model with time-frequency representations(TFR-CDDPM)is proposed. As a generative artificial intelligence(GenAI)method, the original denoising diffusion probabilistic model can effectively learn the probability distribution of vibration responses, but generates data randomly without constraints. To this end, constrained input samples and an improved neural network architecture are introduced to impose prior constraints during training, enabling the reconstruction of missing responses from existing data. Meanwhile, a Fourier transform-based method for constructing two-channel time-frequency input samples is developed, fusing frequency-domain information to improve the reconstruction quality. To validate the model, five accelerometers were installed on a three-span continuous bridge with the middle sensor assumed to be faulty. The results show that compared with the mainstream GenAI method, generative adversarial network (GAN), TFR-CDDPM has a more stable training process and higher reconstruction accuracy, with coefficients of determination (R2) of the reconstructed time- and frequency-domain signals reaching 0.972 and 0.980 on the test set, respectively. The root mean square error (RMSE) and mean absolute error (MAE) of TFR-CDDPM are reduced by 12.0% and 19.7% compared to CDDPM using only time-domain signals. Modal analysis based on the reconstructed responses of TFR-CDDPM indicates that the maximum relative error of natural frequency identification is about -1% and the reconstructed mode shapes are highly consistent with the actual ones, verifying the reliability of the reconstructed responses. Finally, TFR-CDDPM was validated on the Norway Bergsøysund Bridge, showing good reconstruction performance under low-frequency and weak excitations. In summary, this study achieves high-quality vibration response reconstruction by introducing the denoising diffusion probabilistic model framework and time-frequency representations, ensuring the validity of subsequent response-based structural analysis methods.
  • SHAO Chang-jiang, CUI Hao-meng, WANG Chun-yang, JIANG Peng-xu, QI Qi-ming, ZHUANG Wei-lin, LONG Jun-yi
    China Journal of Highway and Transport. 2026, 39(9): 251-259. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.019
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    To investigate the mechanical behavior of laminated-rubber bearing located between the steel plate and concrete pad stone in China's highway beam bridges under earthquake action, the laminated-rubber bearings used in typical small-to-medium-span highway bridges were taken as experimental samples. Steel plates and concrete slabs were set up to form the bearing contact state of the steel-rubber-concrete. The hysteresis relationship and mechanical properties of bearings under multi-stage cyclic horizontal loads were analyzed. The results show that under overpressure, the hysteresis loop of the laminated-rubber bearing is crescent shaped, with a yield sliding point located behind and exhibiting stiffness hardening phenomenon; The bearing only slides at the steel interface, accompanied by the generation of rubber debris. The steel plate is attached with a large amount of rubber material, and the corresponding rubber protective layer of bearings tends to be smooth, while the deformation degree of the rubber concrete interface is slight. After the surface pressure exceeds the normal compressive stress of 10 MPa, the shear displacement and shear stiffness of the bearing protrude, and the sliding degree is insufficient. The friction coefficient of the rubber steel interface follows the order of overpressure>low-pressure>uniform pressure, and does not show a single variation pattern with changes in surface pressure. Under low pressure and uniform pressure, the skeleton curve of the bearing exhibits non-linear changes, while under overpressure, the skeleton curve maintains a linear trend, the laminated-rubber bearing under the contact characteristics of steel-rubber-concrete can be simulated by a bilinear mechanical model.
  • HUANG Fu-yun, CHEN Jun-kun, ZHENG Jie-sheng, XUE Jun-qing, CHEN Bao-chun, XIAO Qiong
    China Journal of Highway and Transport. 2026, 39(9): 260-269. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.020
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    To meet the deformation requirements of bridges and enhance their safety and durability while reducing maintenance workload associated with expansion joints, a novel semi-continuous Ultra-High-Performance Concrete (UHPC) link slab has been progressively implemented. The mechanical performance of the semi-continuous UHPC link slab with a single “T”-shaped joint under compression deformation test was studied. The test results show that the traditional link slab cracked and failed when the compression deformation was only 0.95 mm. The semi-continuous UHPC link slab absorbed longitudinal compressive deformation through its T-shaped expansion joint. At a compressive deformation of 5 mm, no cracks appeared. The UHPC block strain reached 93×10-6, with only slight lateral expansion occurring at the center of the T-flange, demonstrating excellent deformation performance. Furthermore, Increasing the thickness of the longitudinal reinforcement(longitudinal waved steel reinforcement) debonding layer significantly enhances deformation capacity and reduces strain. Specifically, when the debonding layer thickness increases from 0 mm to 10 mm, the elastic compression deformation increases from 1.0 mm to 3.7 mm approximately fourfold and reinforcement strain decreases by 80%. As the wave height of the longitudinal reinforcement increased from 0 cm to 10 cm, the resulting bending deformation distributed stress, leading to a reduction in the strain of the longitudinal reinforcement by approximately 50%. The diameter of the longitudinal reinforcement had a negligible effect on improving the deformability of the specimens. However, a larger diameter led to crushing failure in the UHPC block. Therefore, the diameter of the longitudinal reinforcement should not be excessively large. Overall, under normal conditions, the semi-continuous UHPC link slab exhibits an excellent compressive deformation performance.
  • Tunnel Engineering
  • CAO Kai, ZHANG Qi, LEI Zhong-dai, WANG Kai, ZHOU Zi-hao, YAN Zhi-guo
    China Journal of Highway and Transport. 2026, 39(9): 270-283. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.021
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    Focusing on the deformation characteristics and destabilization mechanism of the surrounding rock of super-large-span flat caverns, the mechanical properties of the surrounding rock during the sequential excavation process was analyzed based on the model tests of excavation by double side heading method. On this basis, the stress perturbation laws, progressive damage mechanism of the surrounding rock, and failure pattern of the support structures during the loading process were investigated through the progressive failure model test. The results show that the support inhibits the displacement of the surrounding rock during the sequential excavation process, giving it a tendency to move away from the cavern. After the excavation of the middle draft, the stress shows a significant decreasing trend. After the removal of the temporary partition wall, the stress is further reduced, showing that the support has a regulating effect on the surrounding rock stress during the excavation process. During the loading process, the support effectively improves the displacement, stress distribution and damage pattern of the surrounding rock. When the support has not yet been damaged, the surrounding rock displacement shows a stable linear growth. When the support is damaged, the growth rate of the displacement is significantly lower than that of the destabilization of the unsupported surrounding rock. Due to the presence of the support, the stress change undergoes a longer rising phase, which significantly enhances the stability of the surrounding rock. The stress changes at the middle measurement points are smaller than that at the end measurement points. The support at the spandrel is a vulnerable position, and the failure of the surrounding rock begins with the shear failure at the spandrel. Compared with the unlined surrounding rock, the support increases the rupture angle of the potential sliding surfaces, decreases the final collapse zone, and improves the bearing capacity of the surrounding rock by approximately 92.46%. The results in this study can provide references for the design and construction of the similar super-large-span caverns.
  • HUANG Ming, CHEN Jun-ning, LU De-chun, LAI Feng-wen, ZHOU Xin, LI Hong-jiang
    China Journal of Highway and Transport. 2026, 39(9): 284-294. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.022
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    Underground pipe roofs are commonly employed to support shallow tunnel excavations in densely populated urban environments, where strict control of structural deformation and internal forces is required. Given that the stringent crown settlement control in shallow tunnels using the pipe-roofing method, this study presents analytical solutions for predicting the mechanical response of pipe roofs subjected to shallow tunnel excavation, incorporating the effects of progressively mobilized soil arching and small-strain soil behavior. Based on the Kerr beam-spring theory, a mechanical model of longitudinally segmented pipe roofs is developed, accounting for their construction behaviors. The vertical load and subgrade reaction coefficients within the excavation influence zone are modified to reflect stress relief, delayed initial support, and excavation disturbance. The Arched Differential Element Method (ADEM) is introduced to compute the vertical stress on the tunnel crown under progressively mobilized soil arching, considering horizontal shear stresses between differential elements. The governing equations for vertical loading on the pipe roof are further derived by incorporating micro-arching effects between adjacent pipes. Moreover, a nonlinear soil-spring model is proposed based on the Hardening Soil Small-strain (HSS) model, capturing stress-dependent stiffness and small-strain behavior. The proposed model is validated against field monitoring data and numerical simulations. A parametric analysis is then performed to examine the influence of tunnel burial depth, soil stiffness and pipe roof bending stiffness on the mechanical response. The results indicate that the maximum deflection error of the pipe roof calculated by the proposed model is only 1.13%, which is significantly lower than that of the conventional method (41.87% error), and the calculated internal force distribution agrees well with numerical simulations. When the burial depth ratio increases from 2.5 to 3.0, the increase in pipe roof deflection is only 3.2%, indicating that the enhanced soil arching effect significantly suppresses deflection growth. Furthermore, when the normalized soil stiffness (Eurref/(γH)) exceeds 350, or the normalized pipe roof bending stiffness (EI/(γH4)) exceeds 2.2, the system exhibits pronounced stiffness redundancy. The proposed model provides a reference for the optimal design of pipe-roof structures in shallow tunnel excavation under urban environments.
  • LIU Jia, YE Fei, PENG Wen-bo, GAO Xiang, HAN Xing-bo, HUANG Shan, ZHANG Zhuo
    China Journal of Highway and Transport. 2026, 39(9): 295-308. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.023
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    To alleviate the tension, depression and visual fatigue caused by poor visual environment in highway tunnels while enhancing drivers' spatial awareness and speed perception, this study explored the improvement measures and optimization methods of tunnel visual environment. Through field surveys, on-site observations, and data analysis of over 80 highway tunnels across 11 provinces, we systematically sorted out the existing improvements and comprehensively evaluated their application effects focusing on three key aspects: Ambient brightness, visual induction, and landscape zone. Research findings indicate that in terms of ambient brightness, the application of LED lighting combined with high-reflectivity interior materials can significantly enhance tunnel brightness and uniformity, playing a notable role in improving visual comfort and reducing lighting energy consumption. Cool-toned interior finishes (such as blue or green) can elevate perceived color temperature, thereby enhance driver attention and shorten reaction times. Segmented coating designs are recommended for the interior of extra-long highway tunnels. In terms of visual induction, facilities like belt lines, reflective rings, and contour markers improve driving guidance and edge recognition by enhancing local brightness and contrast. Combined designs should avoid information overload and coordinate ambient brightness to prevent flicker effects and glare risks. Regarding landscape zone, visual fatigue and psychological strain can be alleviated through landscape design that modulates visual stimuli and reconfigures spatial perception. However, practical implementation often suffers from inadequate or excessive stimulation due to improper brightness and spatial layout. “Scattered” distributions lack continuity, making it difficult to effectively mitigate the oppressive feeling in extra-long tunnels. Based on these findings, this study proposes a visual environment optimization approach centered on drivers' psychological needs, integrating landscape aesthetics. It emphasizes achieving both functional and aesthetic objectives through continuous, rhythmic landscape design that satisfies drivers' visual and psychological demands, thereby enhancing both driving safety and comfort.
  • CHEN Tao, WU Huai-na, WEN Jia, YU Man, CHEN Ren-peng
    China Journal of Highway and Transport. 2026, 39(9): 309-323. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.024
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    Sprayed ultra-high performance concrete (SUHPC) was used to reinforce tunnels, the interfacial bonding performance between the reinforcement layer and the existing lining was unclear. Through experimental investigation and theoretical analysis, 28 static push-off tests were conducted to examine the effects of spraying technique, interface treatment method, and the strength grade of normal concrete (NC) on the failure mode and shear behavior of the SUHPC-NC interface. Based on the test results and shear-friction theory, a double-sided shear calculation method for SUHPC and a prediction model for the load-slip curve were proposed. Results show that the failure modes of the specimens include three forms: interfacial debonding, partial NC failure, and NC diagonal shear failure. After interface chiseling, the interfacial shear strength and shear stiffness of SUHPC-NC reached 4.07 MPa and 1 058.1 kN·mm-1, respectively. Compared with the smooth treatment, these values increase by 113.1% and 237.3%. The strength grade of normal concrete has limited influence on interfacial shear strength. Compared with C30 concrete, the interfacial shear strength of C40 and C50 concrete increase in the range of 3.9% to 14.3%. The interfacial shear strength of vault top-spraying decrease significantly compared to sidewall side-spraying. The reduction ranged from 30% to 40%. Interface planting enhances the interfacial bonding of vault spraying. Compared with sidewall spraying, the reduction in interfacial shear strength is 11.5%. A calculation method for the interfacial shear strength and load-slip curve of SUHPC-NC is established. Forty-five valid test sets from domestic and international sources are collected for verification, and the average error of shear strength is less than 10%. This can provide a theoretical basis for the design of SUHPC-NC composite structures in practical engineering.
  • Traffic Engineering
  • DONG Wen-tao, YU Cheng-cheng, LI Xi, YUAN Quan, YANG Chao
    China Journal of Highway and Transport. 2026, 39(9): 324-335. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.025
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    Customized bus services, with their high flexibility and strong customization, hold significant potential for filling service gaps in traditional bus and urban rail systems. To effectively deploy customized bus routes, large volumes of individual mode choice data are needed to accurately identify the spatiotemporal distribution of travel demand. However, the scarcity of individual choice data and the preference heterogeneity have constrained the precise planning and deployment of such services. To address this challenge, this study developed a two-stage modeling framework. An unsupervised clustering method based on service matching was applied to identify the potential demand for customized buses from existing travel data, thereby generating individual-level choice labels. A mode prediction model based on Mixture-of-experts was built to capture the heterogeneous preferences of customized bus choice. Empirical analysis using data from Shanghai shows that this framework can generate individual choice data that closely aligns with actual passenger flows without relying on traditional surveys. The proposed model achieves an 8.9% improvement in prediction accuracy over traditional discrete choice models and machine learning models. These advantages stem from its ability to reveal heterogeneous trade-offs among accessibility, timeliness, and cost in individual decision-making. Through analysis of the mechanisms underlying customized bus choice, three typical demand scenarios were identified: peak-hour feeder travel to rail transit, leisure trips by university students, and child pick-up and drop-off trips by middle-aged and elderly passengers. The findings provide a theoretical basis for the refined design of customized bus services.
  • CHEN Jing, ZONG Chang-ming, YUAN Chang-wei, MA Ning-yuan, ZHANG Jie, ZHANG Ming-hui, FANG Xin-jie
    China Journal of Highway and Transport. 2026, 39(9): 336-351. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.026
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    To address the limitations of existing taxi dispatching methods, which often focus on optimizing the interests of only one or two stakeholders among platforms, passengers, and drivers, and to overcome the low solution efficiency of traditional methods in dynamic environments, this study proposes a multi-objective taxi dispatching optimization method based on deep reinforcement learning. First, the taxi order dispatching problem is formulated as a Markov decision process. The dispatching platform is modeled as the agent, and prioritizing orders from a selected grid cell is defined as the action of the platform agent, which improves the efficiency of order dispatching. Second, a multi-objective reward function is designed by integrating platform efficiency, passenger waiting time, driver income, and drivers' preferred operating areas, so that the interests of multiple stakeholders can be considered simultaneously. Finally, a Deep Q Network is used to learn the order dispatching policy, enabling efficient decision making and long term reward optimization in dynamic environments. The proposed method improves order response capability and enhances passengers' waiting experience, while also better accounting for drivers' preferred operating areas and achieving coordinated optimization among multiple stakeholders.Experiments on a Xi'an taxi order dataset during the morning peak period over a complete week show that the proposed method outperforms the average performance of four baseline methods. Specifically, the order response rate and total revenue increase by approximately 13.42% and 10.37%, respectively, while the 95th percentile response time and average pickup time decrease by approximately 13.17% and 36.17%, respectively. In addition, the proposed method maintains a high order response rate with low decision time, indicating its practical value in large scale, dynamic, and real time order dispatching scenarios. Ablation experiments and multi-objective emphasis experiments further show that passenger waiting time and drivers' preferred operating areas are major factors affecting order dispatching performance. A balanced weight setting can provide a more reasonable trade off among platform efficiency, passenger experience, driver income, and drivers' preferred operating areas. The findings provide a reference for precise taxi fleet allocation and the optimization of urban transport supply and demand balance.
  • Automotive and Mechanical Engineering
  • HE Yi, HU Hong-bin, ZHANG Ming
    China Journal of Highway and Transport. 2026, 39(9): 352-362. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.027
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    In autonomous driving systems, trajectory planning in cluttered environments must not only generate collision-free trajectories but also strictly satisfy vehicle dynamic constraints and real-time requirements, making it a typical high-dimensional nonlinear optimization problem. In particular, full-dimensional obstacle avoidance modeling, which aims to accurately characterize the geometric relationship between the vehicle and surrounding obstacles, often requires a large number of auxiliary variables. This leads to a strong coupling between obstacle avoidance constraints and the vehicle dynamics model, resulting in excessive computational cost. To address this issue, this paper proposes a trajectory optimization framework based on the Alternating Direction Method of Multipliers (ADMM), which decomposes the original coupled problem into two subproblems through a structured decomposition strategy: an obstacle avoidance subproblem and a dynamics subproblem. Specifically, the full-dimensional obstacle avoidance constraints are reformulated using affine transformations and further converted into smooth and differentiable forms based on convex duality theory, allowing the obstacle avoidance subproblem to be cast as a standard quadratic programming (QP) problem and efficiently solved using the dedicated QP solver OSQP. Compared with existing methods that rely on second-order cone programming (SOCP) or generic nonlinear solvers, the proposed method significantly reduces computational complexity. Meanwhile, the dynamics subproblem is strictly confined to the state and control variable space, which enables an analytical iterative linear quadratic regulator (iLQR) to be directly applied in place of conventional nonlinear solvers for efficient computation. Simulation results show that, while maintaining trajectory quality and modeling accuracy, the proposed method significantly reduces the overall computation time compared with mainstream methods such as H-OBCA and RDA. In particular, the computation time for solving a single dynamics subproblem is reduced by a factor of 26, substantially improving the practicality and scalability of trajectory optimization in dense multi-obstacle environments.
  • ZHANG Hang, LIU Ying-wei, ZHAO Ke, YE Min
    China Journal of Highway and Transport. 2026, 39(9): 363-372. https://doi.org/10.19721/j.cnki.1001-7372.2026.09.028
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    To address the challenges in fault diagnosis of rotating mechanical components in highway equipment, where source-domain data are unavailable, cross-domain distributions differ significantly, and category spaces are inconsistent, this paper proposes a universal source-free domain adaptive fault diagnosis method for multi-class shift scenarios. The method decouples target-domain representations into domain-shared features and class-discriminative features via a feature decomposition mechanism, and employs reconstruction and feature consistency constraints to achieve target-domain adaptation without accessing source data. Meanwhile, a two-component Gaussian probability model is constructed to characterize the confidence distribution of target-domain samples, and a dynamic thresholding strategy is applied to identify and suppress potential unknown-class samples, thereby mitigating negative transfer caused by unknown faults. Furthermore, a pseudo-label self-training strategy is introduced to iteratively refine class boundaries and feature clustering structures. Nine cross-domain diagnostic experiments under four different scenarios were conducted on the rotating machinery component dataset of highway equipment, The results show that the proposed method achieves an average diagnostic accuracy exceeding 88%, representing a 5%-10% improvement over existing source-free transfer methods, including Method 6 (entropy-optimized neighborhood clustering) and Method 7 (source similarity metric adaptation). The results demonstrate that the proposed approach effectively handles both distribution and category shifts under source-free conditions, providing a feasible solution for reliable cross-domain fault diagnosis in highway equipment and supporting intelligent operation and maintenance.