During subway train operation in tunnels, piston wind is generated, which significantly affects the tunnel flow field. Understanding piston wind characteristics is crucial for its effective utilization. It is of great significance to study the characteristics of piston wind for rational utilization of piston wind. Based on Bernoulli equation of unsteady flow, a lumped parameter theoretical model of piston wind in subway tunnel is established, and the characteristics of unsteady piston wind are analyzed. In order to verify the accuracy of the theoretical model, a reduced size model test bench of 1:16 was established, and the piston wind speed was tested experimentally. The comparison between the model value and the measured value shows that the Pearson correlation coefficient is higher than 0.98, and the average error is lower than 13%, which verifies the correlation and accuracy of the theoretical model. By using the lumped parameter theory model, the influence of different factors on the piston wind in subway tunnel is explored, and the grey correlation degree is analyzed. The results show that the congestion ratio is the biggest factor affecting the ventilation effect of the tunnel piston, followed by the train length and train speed, and the tunnel length is the least. Based on this, a fitting formula for the ventilation effect of the piston in common subway tunnels in China is proposed.

Current lighting control methods for urban rail transit platforms suffer from simplistic control mechanisms and low accuracy, leading to significant energy waste and failure to provide passengers with a comfortable lighting environment. Based on the characteristics of passenger flow, zonal functional features, and psychological needs of passengers, this paper proposes an energyefficient lighting control method for urban rail transit platforms using passenger density as the primary parameter. The method first establishes a functional relationship between passenger density in different zones and time periods and the required illuminance levels by analyzing the spatial characteristics of platforms and temporal variations in passenger psychology. Subsequently, a linear programming optimization model is developed with the goal of minimizing platform lighting energy consumption, subject to illuminance requirements, using luminaire dimming coefficients as control variables. The model is solved using the simplex method, and case studies are conducted. The results show that in lowpassengerflow stations, compared to conventional control methods, the proposed method reduces platform lighting energy consumption by 27.68%, 38.16%, and 38.87% during morning peak, evening peak, and offpeak periods, respectively, while maintaining illuminance levels within the appropriate range. This method effectively reduces energy consumption and enhances the lighting comfort of urban rail transit platforms.

Addressing the challenge of shallowburied box tunnel machine passing under significant risk sources, this study takes the closerange underpass of the expressway by the underground passage box tunnel machine at Sanyuanqiao Station of Beijing Subway Line 12 as the background. Numerical simulation was used to precisely model the roadbed pavement structure layer of the expressway and simulate the entire construction process of the underpass. The ground surface deformation patterns caused by the box tunnel machine under the expressway were analyzed, and a parameter sensitivity analysis was conducted on construction parameters such as the support pressure at the pipe head, ground loss, and grouting pressure during the pipe jacking construction. Finally, video monitoring was used to monitor and verify the settlement of the expressway. The results show that the ground surface deformation caused by shallowburied box tunnel machine can be summarized into three stages: slight surface uplift, rapid surface settlement, and final settlement stabilization. Changes in ground loss and grouting pressure are the most sensitive to settlement variation. The established numerical model can reflect the basic patterns of surface deformation caused by pipe jacking construction, as indicated by onsite video monitoring data. The maximum settlement of the highway surface meets the control standard of ≤15 mm.

To ensure the structural safety of existing shield tunnels during nearzero distance deep excavation and address the challenges of retaining structure construction and ground reinforcement under low clearance conditions, this paper presents a case study of a pump station excavation project in the Yangtze River floodplain area. The protection measures include Metro Jet System (MJS) piles with Hsteel insertion using highfrequency hydraulic resonancefree hammer, and synchronous prereinforcement inside the shield tunnel using longitudinal braces and filament wound profiles. Through comparative analysis of threedimensional numerical simulation and field monitoring data before and after deep excavation, the soil squeezing effect and timespace effect on the tunnel structure were effectively controlled. These findings can provide valuable reference for the design and construction of similar excavation projects.

The fully automatic operation (FAO) system has become the mainstream of urban rail transit in China. Considering factors such as safety and timeliness of emergency response, at present, FAO lines in China still operate in a staffed manner, failing to give full play to the fully automatic advantage. To address the concerns of operation units and improve the efficiency of emergency response for equipment failures, this paper proposes an emergency plan framework related to FAO line directed by key equipment based on extensive survey on the current emergency plans of fully automatic operation lines in multiple cities. Aiming at the problems of insufficient completeness and poor operability of current emergency plans, a design method of emergency plans for fault handling that integrates failure mode analysis (EMEA) and entropy weight method (EWM) is proposed. Considering five factors such as the severity, occurrence probability, scope of influence, difficulty of isolation, and difficulty of operation restoration, objectively calculate the comprehensive fault impact index, combined with system design information and operation log data. Based on this impact index, operators can determine the fault handling strategy and design the emergency plans. Finally, taking the axle counter equipment as an example, the equipment fault mode is classified and an emergency plan is designed targeted with 85 months of fault log data of a certain line. The results show that the completeness and operability of the failure handling emergency plan have been effectively improved.

To address issues such as tongue breakage, platform and bottom plate detachment, and conversion failure in welded slide plates for urban rail transit turnouts, as well as the challenges of complex casting processes, slag inclusion, shrinkage, and high scrap rates in integral cast slide plates, this study proposes optimization and improvement measures. These include enhancements in structural design, casting processes, surface friction reduction, and nondestructive testing. The traditional oil maintenance method, which leads to heavy maintenance workloads, track contamination, erosion of fastener backing plates, and reduced durability, is replaced with a new design approach. The reliability and superior performance of the newly developed integral cast slide plate were validated through theoretical analysis and laboratory tests, followed by online trial installation. Results indicate that the new integral cast slide plate significantly reduces maintenance workloads in turnout areas, enhances maintenance convenience, and offers valuable insights for future optimization and defect management of turnout slide plates. Key aspects of the design, production, and testing of slide plates were optimized and improved, focusing on structural design, casting processes, surface friction reduction, and non-destructive testing. The reliability and superior performance of the newly developed integral cast slide plate were validated through theoretical analysis and laboratory testing, followed by online trial installation. Results from the trials demonstrate that the proposed integral cast slide plate significantly reduces maintenance workloads in turnout areas, enhances maintenance efficiency, and offers valuable insights for future optimization and defect management of turnout slide plates.

To address the issue of settlement in existing subway tunnels due to the construction of new adjacent tunnels, an automated machine learning approach and a strategy for weighting multisource data were employed. A predictive model was developed, taking into account tunnel characteristics, stratum properties, and relative positional relationships as input parameters, with the settlement values of the existing tunnels as the output. The model was tested using tens of thousands of simulation data points and realworld data. The findings suggest that while the automated machine learning algorithm can produce a highly accurate predictive model based on simulation data, it may not perform as well with multisource data sets. By assigning weights to multisource data, the model's ability to generalize can be improved, leading to an optimized model that specializes in realworld data, based on simulation data. When the quantity of weighted realworld data is comparable to the simulation data, the model's error rate is reduced. Additionally, according to the feature importance of the bestperforming model, the stratum loss rate emerges as a critical input parameter for prediction, with the significance of geological conditions, spatial relationships, and construction attributes being nearly equivalent.

In order to analyze the development and current research status of urban rail transit network performance evaluation, in urban rail transit networks this paper conducts a quantitative analysis of the literature from the CNKI database based on CiteSpace software. This paper gradually focuses on three levels of research: urban rail transit, urban rail transit network, and urban rail transit network performance evaluation, and analyzes the information such as the number of publications, authors, literature sources and keywords. By tracing the important literature, the main indicators of rail transit network performance evaluation are summarized, and the advantages and disadvantages of different evaluation methods are commented. The results show that the research on performance evaluation of urban rail transit networks is undergoing several important transformations. Firstly, the analytical model is developed from unweighted network to weighted network model, which pays more attention to the differences between stations and intervals. Secondly, the research object was extended from the analysis of rail transit network to the comprehensive evaluation of coupled transportation networks such as railroad and railbus. Finally, the research focus of network performance has gradually shifted from the resistance ability under disasters or external shocks to the resilience evaluation including the postdisaster recovery ability.

To address the difficulty in selecting urban rail transit projects in large cities, a model for evaluating the selection of urban rail transit construction projects was constructed based on the analytic network process (ANP). Based on the policy requirements and the demands of relevant stakeholders, five evaluation criteria are proposed: urban coordination, social impact, construction implementation costeffectiveness, postconstruction traffic effects, and network service improvement. These criteria are further refined into nine evaluation indicators. An evaluation model operation platform was constructe, and the evaluation model was verified using a city in Southwest China as a case study. The technical route of the evaluation model conforms to the decisionmaking logic for selecting urban rail transit construction planning projects. The input data of the evaluation model are all data that can be obtained during the construction planning phase. The output results of the evaluation model can intuitively reflect the priority ranking of the candidate projects.

To investigate the diffusion mechanism of backfill grouting slurry in metro tunnels under different working conditions during the operation period, a mathematical model of the diffusion process was derived based on the physical processes involved in grouting. A threedimensional numerical simulation program, developed using the finite element method (FEM) and the volume of fluid (VOF) method, was applied. Using an actual project during the operation period as a case study, the diffusion behavior of backfill grouting in metro tunnels under different soil conditions was simulated, and the rationality of the numerical simulation results was validated through laboratory model tests. The results indicate that in hard soils, the slurry predominantly fractures in a direction perpendicular to the lining structure, making it difficult to form a large closed reinforcement area behind the lining. In contrast, in soft soils, as the grouting pressure increases, the slurry gradually spreads along the interface between the tunnel and the soil. Upon completion of grouting, the slurry forms a uniformly distributed closed reinforcement along the tunnel wall. The consistency between the model test and numerical simulation trends confirms the reliability of the grouting diffusion mechanism behind the tunnel wall.