To address the data security risks arising from the explosive growth of railway passenger transport data, the core lies in achieving intelligent identification and dynamic protection of sensitive information. Then, an intelligent identification technology for sensitive data in railway passenger tickets based on data knowledge base is proposed. Firstly, a three-level knowledge base of "laws and regulations-industry standards-enterprise norms" is constructed. Secondly, combined with historical railway passenger ticket data, a multi-level intelligent identification algorithm for sensitive data is designed, thereby efficiently and accurately identifying sensitive information in multi-modal data. On this basis, the graph technology is finally introduced to construct a data asset and sensitive data lineage graph, and based on the topological relationship of data flow, the efficient propagation of sensitive information labels among related data nodes is achieved. The results show that the sensitive information identification efficiency of the proposed technology reaches about 217 000 messages per second in structured data processing, which is almost twice as high as the traditional solution. In unstructured data processing, through domain knowledge graphs injection, the F₁ value of sensitive entity recognition is increased to 91.24%, and the context misjudgment rate is reduced to 5.88%. The accuracy of text extraction and sensitive information recognition of multimedia images reaches 93.71%. This technology can significantly improve the accuracy and processing efficiency of sensitive data identification in railway passenger tickets.

To investigate the characteristics of the initial compression wave associated with tunnel sonic boom in long high-speed railway tunnels and analyze its correlation with the occurrence of tunnel sonic boom, full-scale tests were carried out in a long tunnel. Taking the formation mechanism of tunnel sonic boom and the propagation path of the initial compression wave as the starting point, the longitudinal distributions of the aerodynamic pressure and pressure-gradient peak of the initial compression wave inside the tunnel before and after the occurrence of sonic boom were comparatively analyzed. The influence of train speed on these peak values during sonic boom occurrence was clarified, and the effects of portal hood configuration and train type on tunnel sonic boom were discussed. The results show that, under the action of nonlinear effects, the initial compression wave is progressively steepened during propagation, thereby inducing tunnel sonic boom. For the tested tunnel, regardless of whether sonic boom occurs, the aerodynamic pressure peak of the initial compression wave along the tunnel longitudinal direction first increases and then decreases. When sonic boom occurs, the pressure peak of the initial compression wave near the train exit end is higher than that near the entry end. Taking a train speed of 340 km · h^-1 as an example, the positive peak, negative peak, and peak-to-peak value of the aerodynamic pressure of the initial compression wave at the measurement point near the exit end increase by 36.53%, 11.22%, and 20.71%, respectively, compared with those near the entry end. With increasing speed, the probability of tunnel sonic boom increases, and the variation rate of the aerodynamic pressure peak of the initial compression wave from the train entry end to the middle section of the tunnel is higher than that at lower speeds. When sonic boom occurs, the pressure-gradient peak of the initial compression wave increases sharply after propagating a certain distance, and the increase near the train exit end is significantly greater than that near the entry end; at 340 km · h^-1, the difference between the two reaches nearly ninefold in the tested tunnel. When sonic boom occurs, the pressure-gradient peak inside the tested tunnel is proportional to the train speed raised to the power of 6.5-9.6, whereas when sonic boom does not occur, it is proportional to the train speed raised to the power of 3.5-4.6. In addition, compared with the recessed portal hood, the oblique portal hood is more effective in mitigating the occurrence of tunnel sonic boom.

By means of three-dimensional CFD numerical simulation method, the spatiotemporal distribution law of aerodynamic pressure on the tunnel wall and vehicle surface in the horizontal and vertical directions during single vehicle passage and double vehicle intersection of CR400 EMU with a speed of 400 km ∙ h^-1 is studied, and the negative pressure area and boundary conditions on the tunnel wall and vehicle surface are quantified. The results indicate that the aerodynamic pressure inside the tunnel can be correlated with parameters such as vehicle type, train speed and tunnel length to form a theoretical model. When different types of single vehicle pass through the tunnel at a speed of 400 km ∙ h^-1, the difference in peak aerodynamic pressure acting on the tunnel wall is limited. Compared with the CR400BF EMU, the CR400AF EMU only increases the positive peak of aerodynamic pressure by 1.1% and the negative peak of aerodynamic pressure by 0.9%. The aerodynamic pressure on the surface of the EMU shows high uniformity in both the horizontal and vertical directions. During single vehicle passage and double vehicle intersection, the surface of the vehicle body is basically in the same pressure state at the same time. At different tunnel lengths, when the speed of the EMU is 400 km ∙ h^-1, the negative pressure of the expansion wave at the center of the tunnel and the negative pressure of the high-speed train body itself are superimposed when a single vehicle passes through the tunnel, and the negative peak value of the aerodynamic pressure borne by the body reaches -4.60 kPa. When 2 vehicles intersect at different positions with a constant speed inside the tunnel, the maximum negative pressure occurs at the intersection condition of the tunnel center, and the negative peak value of the aerodynamic pressure reaches -9.68 kPa. When 2 vehicles intersect at a constant speed in the center of the tunnel, there is an unfavorable velocity boundary that significantly strengthens the negative pressure effect in the intersection negative pressure area.

To address the mechanism analysis and treatment of inverted arch uplift and track slab cracking in an in-service tunnel, a combined approach of field structural disease characteristic analysis and laboratory tests was adopted to explore the disease mechanism of inverted arch uplift deformation and track slab cracking in an in-service tunnel of the Shanghai-Kunming Railway. According to the analysis of structural cracking characteristics and disease mechanism, integrated treatment measures of "grouting anchor pipe installation - bedrock grouting and removal - reconstruction of inverted arch structure" was proposed. These measures were adopted to guide the construction of the background project, and the evolution laws of the contact stress between the bedrock and the inverted arch was monitored and analyzed during the construction process. The results indicated that: the expansion deformation of bedrock upon water exposure was the main cause of local uplift of the inverted arch and other supporting structures, leading to increased internal forces, uneven deformation, and cracking; factors such as bedrock bearing capacity reduction, stress concentration induced by local high in-situ stress, and uneven stiffness and stress distribution in the invert arch structure further exacerbated the risk of non-coordinated deformation and cracking in the bedrock-invert arch system; the contact stress between the bedrock and the reconstructed inverted arch showed a phased evolution pattern, initially increasing slowly and then gradually converging to stability. The average contact stresses at three monitoring sections were 167.83, 169.51 and 165.82 kPa, respectively, which ensured the stability and safety of the tunnel structure. The treatment measures in combination with the disease mechanism analysis effectively prevented and controlled inverted arch uplift and structural cracking in the in-service tunnel. The research results provide a design scheme and engineering application reference for the treatment and prevention of similar engineering diseases.

To clarify the stress characteristics and failure mechanism of inclined bolt joints in subway shield tunnel segments, firstly, full-scale tests were designed and carried out on 2 adjacent segment standard blocks based on the supporting engineering. The stress-strain development law of concrete in each part of the inclined bolt segment joint during bearing was analyzed, and the failure process of the segment joint was studied in stages. Then, a numerical model was established to compare the failure process and characteristic change laws of segment joints under 2

To further enhance the intelligent recognition, assessment, early warning, and active prevention and control capabilities of high-speed railways in responding to risks such as natural disasters, perimeter invasion/foreign object intrusion, and external environmental safety, a method for active perception and early warning of the operational environment safety of high-speed railways is proposed based on the concept of active control of high-speed railway operating environment safety. By analyzing the action mechanism and spatiotemporal evolution patterns of the main influencing factors on the operational environment safety of high-speed railways, the disturbance mechanisms of various risk sources on train operation are revealed. On this basis, a situational awareness method for the operating environment safety across full spatiotemporal scenarios is designed, covering refined forecasting of meteorological disasters, multi-modal fusion-based recognition of perimeter invasion/foreign object intrusion, and intelligent perception of external environmental hazards through air-space-ground collaboration. Corresponding intelligent assessment and early warning models are then constructed, and active control and emergency response strategies are formulated. The results show that the accuracy of refined gale situational awareness for wind speed forecasting reaches 93%. Compared with the existing similar intelligent methods, the transmission delay of alarm information from system generation to train's beyond-visual-range terminal display is reduced from 2.364 s to 1.651 s. This method can provide a systematic solution for engineering applications and demonstrate promising prospects for practical implementation.

Given the significant randomness of vehicle-bridge dynamic response for higher-speed railways, this study aims to explore the characteristics and probability distribution of dynamic response of a 400 km · h^-1 train passing through a bridge. A vehicle-bridge coupled random vibration model is established based on the pseudo-excitation method and the whole-process iteration method, and its validity is confirmed through comparison with the simulation results of Monte Carlo method. Based on this model, the time-frequency distribution laws of safety and stability indices of the train running at 400 km · h^-1 are analyzed, and the random characteristics of vehicle-bridge dynamic response under higher speeds on simply-supported beams with different fundamental frequencies are studied. The results show that the statistical values of vehicle-bridge response vary with time, showing typical non-stationary characteristics. The dynamic coefficient of the bridge is mainly controlled by the arrangement of train axle and the wheelbase, and is only slightly affected by the random excitation of track irregularity. Under resonance conditions of simply supported beam, the wheel load reduction rate increases significantly with the increase of speed, and the carbody vibration acceleration is insensitive to the resonance response of the simply supported beam. The fundamental frequency of the simply-supported beam has minor effect on the wheel load reduction rate and carbody vibration acceleration, whereas the randomness of the track irregularities has a significant effect on the vertical vibration acceleration and the wheel load reduction rate of the bridge.

With the development of high-speed railways towards 400 km · h^-1 and higher speed levels, train operation safety and ride comfort impose more stringent requirements on track regularity. Focusing on track regularity of simply-supported bridges with common spans widely used in high-speed railways, a refined track-bridge finite element model is established to reveal the inherent mechanism of periodic track irregularities induced by creep camber of bridge girders. Furthermore, an analysis element for periodic track irregularities on bridges suitable for dynamic simulation is proposed. Based on the established vehicle-track-bridge coupled dynamic model for higher-speed railways, the influence of periodic track irregularities on the carbody response of trains running at 400 km · h^-1 is investigated in depth. The results show that an increase in girder creep deformation directly leads to increased rail deformation, with a significant linear correlation between their amplitudes, and the peak rail deformation is always slightly lower than that of girder creep. The proposed calculation element for periodic track irregularities exhibits better consistency with the waveform variation of measured track irregularities. Under the excitation of periodic irregularities, obvious spectral peaks appear at the harmonic frequencies corresponding to a 32 m wavelength in the carbody response spectrum, with the maximum peak occurring at the second harmonic, indicating that the carbody is more sensitive to the excitation of 16 m wavelength, resulting in a double-peak characteristic of the carbody dynamic response within the 32 m wavelength range. The findings provide theoretical support for track condition assessment and track regularity control of 400 km · h^-1 high-speed railways.

To address the engineering problem of aggravated micro-pressure wave hazards at the portal of a 400 km · h^-1 high-speed railway tunnel, this study investigates the radiation characteristics of micro-pressure waves under the coupled effects of actual terrain and buffer structures. Based on the three-dimensional unsteady compressible Navier-Stokes equations and the SST k-ω turbulence model, and using the tunnel equivalent diameter D (10 m) as the characteristic scale, the study systematically examines the radiation characteristics, including peak wave pressure, waveform, attenuation laws, and spatial directivity, of micro-pressure waves under conditions with and without buffer structures at the tunnel exit; it also studies simple flat terrain and semi-cut-semi-fill actual terrain. The results show that the buffer structure pre-radiates micro-pressure waves through side openings, effectively reducing the intensity of micro-pressure waves in the axial direction (directly in front of the tunnel alignment, azimuth θ=0°) at the tunnel portal. The buffer structure effectively reduces the peak value and alters the waveform at 2D, but causes an increase in peak value at 8D, and also enhances micro-pressure waves in lateral directions (e.g., θ=+45°, +90°). Terrain variation has a relatively weak influence on micro-pressure waves in the tunnel axis direction but significantly affects the areas on both sides: the peak micro-pressure wave at the cut (θ>0°) is greater than that on simple flat terrain, while the peak at the fill (θ<0°) is the lowest. The cut slope has a concentrating effect on micro-pressure waves in the area below the cut top, whereas the fill terrain disperses the propagation paths, leading to lower peak values. The attenuation rate of micro-pressure waves is smallest along the tunnel axis and accelerates significantly as the azimuth angle θ increases; for the same azimuth angle, the attenuation at the cut is greater than that at the fill. The directivity of micro-pressure waves is significantly influenced by the buffer structure and actual terrain. When the propagation distance reaches 5D, the influence of the buffer structure becomes negligible, and terrain dominates the directivity - simple flat terrain exhibits axial directivity, while the semi-cut-semi-fill terrain shows directivity in the [0°, +45°] interval due to the concentrating effect of the cut and the dispersing effect of the fill. The research results provide an important theoretical basis for optimizing and design of buffer structures and terrain treatment at the portals of 400 km/h high-speed railway tunnels.

To meet the requirements of modern railway bridge emergency repair, a technical scheme for a deployable medium-span emergency repair girder based on telescopic diagonal web members is proposed. The girder utilizes deployable frame units as its basic components, enabling folding and deployment through the extension and retraction of the diagonal web members. This design resolves the technical challenge of balancing assembly efficiency with storage and transportation space in existing repair girders, while also meeting the emergency repair demands of both conventional-speed and high-speed railway bridges. Finite element analysis models and multi-body dynamics models are established to conduct static analysis and vehicle-bridge coupled dynamic response analysis on the deployable railway emergency repair girder. The results indicate that the stress levels and displacements of the deployable repair girder meet the limit requirements of the “Code for Design on Railway Bridge and Culvert”. The member stresses are highest under the loading of mixed passenger and freight railway traffic. The arrangement of the diagonal web members significantly influences the ultimate bearing capacity of the deployable girder, with the inverted V-shaped configuration yielding a higher ultimate bearing capacity. Among the three truss configurations for the 32 m span, the heavy truss emergency repair girder exhibits superior dynamic response indices. The wheel load reduction rate is identified as the key factor controlling train speed, and the speed limit for high-speed trains crossing the 32 m span deployable railway emergency repair girder can be controlled at 120 km · h^-¹.