Subway Station Research Articles

Research on the Mechanism of Load Transfer Structures in the Construction Process of “Internal Support—Large Block” Prefabricated Subway Stations

In the context of rising global temperatures, countries around the world are increasingly tailoring their own “carbon neutrality” plans. China has also formulated its “dual-carbon” goals, and the construction industry is gradually transitioning towards prefabrication to reduce carbon emissions. This paper uses the Sha Pu Station of Shenzhen’s Metro Line 12 as a case study by which to explore the effects and mechanisms of the load transfer structure during the assembly process of prefabricated subway stations. A three-dimensional finite element model considering soil–structure interaction was established using MIDAS GTS NX finite element software, 2018 version. The internal forces, stresses, and deformations of the station structure were compared under two scenarios—with and without the load transfer structure—using a control variable method. The research results indicate that the load transfer structure effectively reduces shear forces, bending moments, and stresses in the station structure; limits lateral displacements during the assembly process; and effectively concentrates the maximum stresses during construction at the location of the load transfer structure, thereby preventing stress concentration phenomena and enhancing the overall stability of the station structure. This study elucidates the role and effectiveness of the load transfer structure during the assembly of prefabricated components in subway stations, providing a reference for the construction of similar prefabricated metro stations.

Modelling study on pedestrian evacuation dynamics considering exit selection behaviour under flood disaster

Flood spreading in metro stations is a dangerous hazard that frequently causes casualties and property losses. However, pedestrian evacuation under flood spreading scenarios has not been fully investigated. To fill this gap,we propose an extend Floor-Field model incorporating flood spreading and exit selection behaviour of individuals. In the model, the dynamic flood spreading process on metro platforms is expressed by using a simulation software named Mike21. The optimal exit selected by pedestrians in each step is decided on three factors, that is pedestrian density around the exit, pedestrian distance to the exit, and water depth at the exit. Meanwhile, the movement speed of pedestrain also changes with the water depth at each time step. Based on this, the transition probability to neighbor cell including static field, dynamic field, height field, and water flow field is calculated. This results in a flood evacuation model considering the pedestrian's behaviour when choosing an exit. The effects of flooding, pedestrian density, different exit selection behaviours, water flow field, and inlet flow on evacuation were thoroughly analysed. The analysis demonstrates that the likelihood of flooding significantly impacts the evacuation of pedestrians from the subway station; the more flooding is taken into account, the more influential the impact. In addition, the effect of inlet flow on evacuation is also noteworthy; considering exit selection behaviour can significantly increase the effectiveness of evacuation. The study's findings can be used to develop evacuation plans for flooded metro stations.

Do ride-hailing congestion fees in NYC work?

What is the impact of congestion policies targeting ride-hailing systems? This work empirically evaluates NYC’s congestion surcharge policy, particularly in light of the city’s forthcoming implementation of congestion pricing. Using a Difference-in-Differences (DiD) framework, our analysis reveals a statistically significant reduction of approximately 11% in overall ride-hailing travel volume following the implementation of the policy. In particular, Lyft experienced a 17% reduction in travel demand while Uber and yellow-cabs experienced reductions of about 9% and 8% respectively. We further elucidate two key mechanisms — travel distance and subway station availability — to explain this reduction. The surcharge policy has a more pronounced impact on shorter trips (with the most significant decline observed in trips less than one mile), and on ride-hailing trips originating from areas with at least one substitute (such as subway or Citi Bike). Furthermore,the policy’s effect seems more pronounced in lower-income areas of the city and seems to reduce street-hailing industry revenues by 8%. However, despite these reductions, the policy does not result in a corresponding decrease in traffic congestion. Thus, it seems that the policy results in a net welfare loss for the city, at least in the shorter term. Our findings provide insights for understanding the dynamics of congestion policies focused on the ride-hailing industry, especially as New York City prepares to introduce congestion pricing.

Identifying walkability factors for urban metro station areas toward transit-oriented development

ABSTRACT Despite significant efforts to enhance accessibility to transportation facilities and transit-oriented development (TOD), the rapid expansion of cities has hindered improvements in citizens’ access to transportation facilities. This study addresses these challenges by aiming to delineate key factors pertaining to access distance that facilitate successful station area development and to identify areas requiring enhancements in public transport access. To measure accessibility and the factors affecting it, various types of mobility and demographic data, including transit fare card data, residential and workplace population density, and the count of bus stops and metro lines, were used to assess access distance characteristics. Findings indicate that bus stops within 500m of metro stations tend to have more bus stops within a 500m radius and lower residential population within a 100m radius, compared to stations with access distances exceeding 500m. Bus stops in the 500m range outnumber those beyond 500m, and their associated residential and workplace population densities are lower. Considering the number of bus stops as well, stations indicating access distances exceeding 500m are relatively scarce in public transportation, indicating lower public transportation accessibility. Therefore, this study suggests that when developing station areas within urban centres, priority should be given to areas where subway station population density is high but distributed over a wide area and the number of bus stops within the station area is low. These findings on the walkability quality factors and considerations to assess the walkability will be a great reference to the policy decision makers to prioritize TOD areas.

Risk Evaluation of Urban Subway Site Selection: Balance, Attractiveness, and Financing Models

As a crucial form of public transportation, subways are becoming essential infrastructure that cities in China increasingly prioritize for development. However, there is a lack of effective risk assessment methods for subway station and line siting. To address this gap, this paper uses the subway system in Kunming, China, as a case study, establishing a subway site risk evaluation framework (SIRE-BAF) that integrates three dimensions: balance (B), attractiveness (A), and financing mode (F). An extended NP-RV model is proposed to assess the balance (or imbalance) characteristics of subway stations based on sub-dimensions of traffic supply, land use, and urban vitality. Findings indicate that (1) the balance (or imbalance) of subway stations is distinctly distributed along the line and simultaneously exhibits a spatial pattern radiating from the urban core to the periphery. (2) Stations with high urban vitality and minimal imbalance are highly attractive and tend to face “undersupply” during operation, whereas stations with lower attractiveness are more prone to “oversupply”. A higher level of BAF coupling coordination suggests a more suitable subway site selection and lower investment risk, while lower coupling coordination indicates increased risk. (3) Excessive reliance on the “subway + real estate” model, without considering urban vitality, may lead to high vacancy rates and reduced efficiency in subway service. This paper further assesses the site selection risks for the proposed Kunming subway. This study contributes to risk assessments of existing subway operations and maintenance in Chinese cities, enhances planning rationality and site selection for proposed subways, and holds potential applicability for other cities.

Resilience Measurement and Enhancement of Subway Station Flood Disasters Based on Uncertainty Theory

To address the uncertainty of influencing factors in measuring the resilience of subway stations to flood disasters, this study introduces Unascertained Measurement Theory to assess the resilience of subway stations against flood disasters. Initially, the research involves a thorough examination and analysis of past subway flood disaster incidents, which elucidates the disaster system and its resilience processes, thereby facilitating the construction of a resilience analysis framework specific to subway stations. Subsequently, a measurement index system is developed to evaluate the resilience of subway stations against flood disasters, drawing upon relevant literature, and resilience levels are categorized according to established standards. Following this, an unascertained measurement model is formulated to assess the resilience of subway stations in the face of flood disasters. This model incorporates the development of an unascertained measurement function and an unascertained measurement matrix, yielding comprehensive results that inform the determination of resilience levels through credible degree assessment. Furthermore, the SPSSAU obstacle degree model is utilized to analyze the resistance factors that influence the resilience of subway stations to flood disasters, leading to the formulation of strategies aimed at enhancing this resilience. This approach offers novel insights into the measurement of subway station resilience in the context of flood disasters.

Short-term Passenger Flow Prediction of Subway based on Neural Network LSTM Algorithm

The present study investigates the application of the Long Short-Term Memory (LSTM) neural network algorithm for short-term passenger flow forecasting in subway systems. The dataset, sourced from Hangzhou subway stations, records passenger flow at 10-minute intervals over 30 days, distinguishing between weekdays and weekends. The LSTM model was trained using 80% of the available data, while the remaining 20% was reserved for testing purposes. Results showed the model achieved a mean squared error (MSE) of 19.33 on training data, indicating a good fit. However, the test data MSE was significantly higher at 460.78, suggesting overfitting. This implies the model captures training data patterns well but struggles with generalizing to new data. The findings underline the potential of LSTM networks in handling long-term dependencies and gradient vanishing issues inherent in traditional Recurrent Neural Networks (RNNs). Despite these advancements, the study highlights the need for model refinement to address overfitting and improve generalizability. Future research should focus on data augmentation, model enhancement, and regularization techniques to develop more robust prediction models. Accurate short-term predictions of passenger flow play a crucial role in optimizing train scheduling, resource allocation, and overall service quality within urban rail transit systems.

Quantitative analysis of subway station seismic deformation under random earthquakes and uncertain soil properties using the equivalent linearization method

The seismic performance of underground structures is strongly influenced by the characteristics of both the surrounding soil and the earthquake. In contrast to traditional deterministic analysis methods, this study uses a stochastic analysis approach to investigate the effect of uncertainties in nonlinear soil characteristics, shear wave velocity, density, and earthquake randomness on the response of underground stations. The equivalent linearization method is employed to approximate the nonlinear behavior of the soil. The soil was modeled using a linear elastic constitutive model combined with Rayleigh damping in the finite element model. Inter-story displacements are used to determine structural damage. Probabilistic analysis methods are used to obtain their statistical characteristics, and the probability of failure is calculated. The results show that, according to single parameter analysis, random ground motion results in the greatest probability of exceeding the threshold (PET), while ground shear wave velocity significantly affects the coefficient of variation (COV), and the effect of density is the smallest. The study also found that when soil nonlinearity, shear wave velocity, and random ground motion are considered simultaneously, the range, mean, standard deviation, and COV of interstory displacement all increase significantly, but the PET slightly decreases. In summary, the analysis results indicate that random ground motion has the greatest impact on interstory displacement, followed by shear wave velocity, with nonlinear soil characteristics having a smaller effect, and density the least. Therefore, the impact of various uncertainties should be fully considered in the analysis of underground structures, especially random ground motion and shear wave velocity.

Seismic Design of Underground Structures’ Vulnerability – Review.

This article examines the vulnerability of underground structures to seismic activity, with a particular focus on design and mitigation strategies. Underground buildings are essential to the development of modern infrastructure and must include tunnels, subway stations, and storage facilities. Because of its deep location, seismic design and earthquake performance are both more challenging. In this study of seismic susceptibility, topics such as ground motion characterization, soil-structure interaction, structural reaction, and failure mechanisms specific to underground structures are discussed. According to the paper, their susceptibility can be affected by geotechnical conditions, the kind of structures they have, and the construction methods that are used. The seismic stability design and analysis process involves measuring the dynamic response of subsurface structures to seismic loads. The goal is to keep earthquake and seismic forces from toppling structures in any way that is possible. Advanced analytical and numerical approaches are used in seismic stability design. Some examples of these methods are finite element analysis (FEA), discrete element modeling (DEM), and the boundary element method (BEM). In addition to that, it investigates contemporary methodologies for assessing seismic vulnerability as well as international design standards. In addition, seismic retrofitting and design advances for underground structures are analyzed and discussed in this paper. This document compiles and evaluates previous research to gain an understanding of the seismic susceptibility of subsurface structures and to promote more seismic engineering research on this extremely important topic.

Ventilation strategy for particulate matter control in subway stations

Particulate matter severely affects human health, and its migration is closely related to human walking and ventilation. It is essential to select an appropriate ventilation strategy to control the particulate matter caused by cluster passengers walking. In this study, cluster passengers walk in the narrow passage of a subway station. Large eddy simulation (LES) was used to study the influence of cluster passengers walking on the transmission of particulate matter under ventilation conditions involving upper exhaust and lower exhaust. The risk of passengers exposure was analyzed by comparing the exposure levels of particulate matter at different heights under the effect of human disturbance. The results show that the amount of particulate matter near the legs is greatest during human walking. Clustered passengers disturbance airflow induces particulate matter to rise to the breathing zone, which increases the risk of human exposure. Lower-side exhaust conditions are more conducive to the discharge and control of particulate matter. The disturbance of cluster passengers enhances the continuous transmission of particulate matter in the wake flow. This study is applicable to traffic hubs and other public places where passengers gather, the ventilation of the upper side exhaust has better control effect on particulate matter caused by passengers wake flow.

Model test study on the mechanical characteristics of shallowly buried covered excavation PBA station construction

The shallowly buried covered excavation PBA method is one of the new construction methods that has attracted widespread attention in the past 20 years. Understanding the deformation of strata and supporting structures is key to ensuring the safe construction of PBA stations at present. Relying on the Beijing Line 12 Beitaipingzhuang PBA subway station and based on the 1:40 model test, the production of similar materials for the model and the station excavation construction plan are introduced. According to the actual construction process of the station, the construction process of the two stations of the pile foundation and strip foundation stations are more realistic. The variations in the strata around the station and the station structure during the whole construction process are obtained. The test results show that the ground displacement of the station is most affected by the excavation of the pilot tunnel, accounting for more than two-thirds of the total displacement, and the ground within the range of 0–12 m around the station is greatly affected by the excavation disturbance during the actual construction process. By analyzing and comparing the ground displacements and the internal forces of the vertical bearing structure of the two types of stations, it is concluded that the pile foundation method is more advantageous for controlling ground displacement and the internal force of the structure. These test results improve design theory of the PBA method and are conducive to further promotion.

Examining the Impact of the Built Environment on Multidimensional Urban Vitality: Using Milk Tea Shops and Coffee Shops as New Indicators of Urban Vitality

Urban vitality is a critical driver of sustainable urban development, significantly contributing to the enhancement of human well-being. A thorough and multidimensional comprehension of urban vitality is essential for shaping future urban planning and policy-making. This study, focused on Chengdu, proposes a framework for assessing various dimensions of UV through the distribution of milk tea and coffee shops. Using random forest and multi-scale geographically weighted regression models, this study investigates the factors influencing urban vitality from both mathematical thresholds and spatial heterogeneity, and develops spatial maps of future vitality to inform targeted urban strategies. The results show that (1) the milk tea index is effective in capturing population vitality, while the coffee index is more closely associated with economic vitality and urban renewal; (2) office buildings (13.46%) and commercial complexes (13.70%) have the most significant impact on both economic and population vitality, while the importance of transportation factors has notably decreased; (3) the influence of these factors demonstrates spatial heterogeneity and nonlinear relationships, with subway station density of 0.5–0.8 stations per kilometer being optimal for stimulating both types of vitality. The minimum threshold for economic vitality in a given unit is a housing price exceeding 6000 RMB/m2; (4) the future vitality map suggests that urban planners should pay greater attention to non-central districts with high development potential. Moreover, spontaneous social interactions and consumer behaviors stimulated by various shops are critical components of urban vitality. In designing the physical environment and urban spatial forms, special attention should be given to enhancing the attractiveness of physical spaces and their capacity to accommodate social interaction.

Bidirectional seismic response of assembled monolithic subway station-aboveground structure system under artificial bedrock ground motions

Assembled monolithic subway station partly synthesizes the advantages of cast-in-place and precast subway stations. However, the related seismic response analysis considering the influences of vertical ground motion and aboveground structure is still scant. In this study, we firstly performed the statistical analysis on bidirectional bedrock ground motion parameters (response spectrum, duration and envelope function) using KiK-net data, and obtained some suggested values of the above parameters. Then, four sets of artificial bedrock ground motions with statistical meanings were generated and a three-dimensional finite element analysis of the seismic response of an existing two-story three-span subway station was conducted. The main results are summarized below. (1) The significant damage to assembled monolithic station under far-field strong motion firstly occurred at side middle slab; middle slab, upper column and related grouting sleeve joints were more damage-prone. (2) When horizontal peak ground acceleration stayed constant, overall the damage of far-field motion was stronger than that of near-fault motion. (3) Vertical ground motion obviously accelerated the damage progresses of various structural members at various positions, then aboveground structure further enhanced the damages and vertical displacement responses of parts of top slab. (4) For the axial force time-history of upper column during far-field strong motion, aboveground structure uplifted the baseline, and vertical ground motion increased the amplitude and advanced the obvious drop of the baseline, among which the latter effect of vertical ground motion on assembled monolithic station was stronger than that on cast-in-place station. (5) Vertical ground motion enhanced inter-story displacement during far-field strong motion, among which the influence on the upper story of assembled monolithic station could be obviously amplified by aboveground structure, and the amplification effect lagged behind the influence of vertical ground motion. Based on the results of this study, some suggestions for the seismic design of subway station are also provided.

A new Method for Predicting PM2.5 Concentrations in Subway Stations Based on a Multiscale Adaptive Noise Reduction Transformer -BiGRU Model and an Error Correction Method

A new Method for Predicting PM2.5 Concentrations in Subway Stations Based on a Multiscale Adaptive Noise Reduction Transformer -BiGRU Model and an Error Correction Method

Novel Application of a Swift-Assembled Support Method with Prefabricated Corrugated Steel for Vertical Shaft Excavation in a Metro Station

For the construction of a subway station, temporary vertical shafts were commonly used to facilitate machine operation. In densely urban areas, the requirement of settlement control and environmental impact called for a novel construction method of vertical shafts. In this paper, a novel swift-assembled support (SAS) structure and construction method for vertical shafts of a metro station was proposed, using prefabricated steel components. A comprehensive scheme of full-time monitoring was conducted to evaluate the performance of this novel support structure and ground response. Field monitoring results indicated that the SAS method was able to control the settlement of ground and adjacent buildings. Based on the field measurements, the calculation theory for design parameters were discussed. The active earth pressure yield from the method considering wall movement was closer to the field measurements. All of the local buckling values were both overestimated based on the technical standards’ methods. The calculation methods were thereby adopted carefully to determine the designed loading share ratio of structure components. The advantage of the SAS method, including rapid construction, safety, and lower environmental impacts, were obviously clear.

O Bixiga em disputa: ambiente, cultura, memória e interesses imobiliários

Bixiga is currently experiencing a critical situation that threatens the preservation of what constitutes its most unmistakable cultural and environmental heritage, associated with the strong impact caused by the advance of real estate interests, announced by new buildings recently approved by Conpresp in its territory. Particular concern is the vulnerability to which the area known as Grota do Bixiga is being exposed, despite the existence of protective legislation agreed since the early 2000s. Concern is intensified by the fact that these developments create reckless precedents for others to be approved in the near future, thus putting an end to the possibility of preserving what remains of Grota do Bixiga. This approach allows us to look at a whole process of study, inventorying and consolidation of knowledge produced within the Historical Heritage Department, which began in the 1980s, linking architectural assets to the structuring elements of the urban fabric and to the social relationships that not only populate the memory of the place, but are kept alive in the cultural practices of the present. It also allows us to deal with the impasses between cultural heritage preservation policies and urban policies of a broader nature. It also allows us to deal with the impasses between cultural heritage preservation policies and broader urban policies. Finally, it allows us to analyze another layer of latent memory, unveiled by the discoveries linked to the excavations carried out for the construction of the Orange Line Subway Station. The recent archaeological finds have sparked an important debate about the origin of occupation of the neighborhood associated with the presence of the Quilombo Saracura, strengthening the memory of the black population, due to its representativeness and its persistence over time, as an essential element of the culture of the place, which cannot be erased or made invisible.

Study on carbon emission calculation during the materialization phase of subway stations and comparative analysis of carbon emissions from various construction methods

To enhance the low-carbon construction level of subway stations, this paper, based on life cycle theory and the carbon emission factor method, summarizes the carbon emission calculation methods and relevant standards. Preliminary versions of the "Carbon Emission Database Software for subway station Civil Engineering" and "Carbon Emission Calculation Software for subway station Civil Engineering" were developed, enabling rapid calculation of carbon emissions for subway stations. From the perspective of low-carbon construction, a subway station in Guangzhou was used as an example to calculate the carbon emissions of three low-carbon construction methods. The results indicate that: (1) The carbon emission intensity of the materialization phase of the case station using the cover excavation reverse method is 3.46 tCO2e/m², demonstrating a lower carbon advantage compared to the other two methods; (2) The carbon emission of the building materials production phase accounts for over 84 % of the total carbon emission during the materialization phase for all three methods, making it the main source of carbon emission in the materialization phase of subway stations; (3) For subway stations of the same cost, the carbon emission of the open cut method is 13.77 % higher than that of the cover-excavation method and 10.18 % higher than that of the cover excavation reverse method.

Three-Dimensional (3D) Flood Simulation Aids Informed Decision Making: A Case of a Two-Story Underground Parking Lot in Beijing

Flooding in underground spaces, such as subway stations, underground malls, and garages, has increased due to intensified rainfall, urbanization, and population growth. Traditional 2D simulations often overlook crucial vertical flow variations, especially in steep transitions like stairs and ramps. The current study aims to investigate the flood dynamics in large underground geometries by taking a parking lot in Beijing, China, as a study case. The model overcomes the limitations of previous simulations by adapting a full 3D mesh-based simulation with reasonable computational cost. Unlike earlier studies, this model employs a high temporal resolution transient inflow at the inlet to the underground space. Simulation scenarios consider different return periods (5, 20, and 100 years) and inlet water depths, providing an analysis of their impact on flood status in the underground structure. The model generates high spatial–temporal results, enabling precise detection of flood-prone locations, evacuation times, and suggested mitigation techniques. The results recommend evacuating from hazard areas before the 10th minute during extreme flood events. Additionally, the study estimates a 40% increase in flood hazards for scenarios with direct connections between levels. Overall, the study highlights the importance of 3D simulations for accurate risk assessment.

EVALUATION OF REUSE WATER FROM THE PINHEIROS METRO STATION IN THE CITY OF SÃO PAULO (BRAZIL) FOR THE PRESENCE OF METALS USING THE X-RAY FLUORESCENCE TECHNIQUE WITH SYNCHROTRON RADIATION

Ensuring the conservation of water reserves is a challenge for all humanity, which makes it essential to continuously study new ways of treating and using water sources on the planet. One of the focuses of water conservation and sustainability is the reuse of water sources in order to guarantee the continuity of the main reserves of drinking water for activities such as waterlogging and food production. The present study aimed to investigate the quality of the water used for reuse at the Pinheiros subway station in the city of São Paulo (Brazil) in order to assess the degree of presence of heavy metals and other chemical elements using the X-ray fluorescence technique by synchrotron radiation at the National Synchrotron Light Laboratory (LNLS). The data collection for a sample collected in the summer and analyzed revealed a pH of 6.8 and the presence of 19 chemical elements using the technique with concentrations in the order of ng.mL -1 , with emphasis on the presence of lead (Pb).

Exploring the Influence from London Development on London Underground Mobility Through Network Analysis

As cities grows up, people continue to gather in cities, and human activities in cities have become more intense than ever before. These human activities will subtly reshape urban space, causing significant transformation of the urban physical environment and socio-economic environment. The method of big data provides a promising perspective for us to explore the impact of human activities on the urban environment. This study investigates the commuting patterns of London citizens in the subway and explores the impact of human activities on the importance of network nodes in subway stations. We use network analysis to characterize the node’s importance through degree, closeness, and betweenness centrality, and then compare these centralities with the centrality with the human mobility as weight. The result shows that the node’s importance based on centrality characteristics are largely reshaped by human mobility, which in turn drive the government to build new lines to hold the mobility flow. This research is helpful for providing insights for the London subway and urban construction.