Existing Metro Station Research Articles

Deformation caused by T-shape expansion of existing metro station: complex challenges and strategies

This case study presents an investigation on existing metro station deformation characteristics during T-type expansion in Nanjing, China. A three-dimensional elastic-plastic finite element model is adopted to consider the interaction of soil, retaining structure, horizontal support system and existing station structure. The results indicate that coupling deformation of asymmetric uplift deflection and existing structure rotation occurs on existing structure. Moreover, the sensitivity of influencing factors is analyzed, including the dimension of retaining structure, the support spacing, the excavation method, the soil reinforcement depth in passive area, the width of retaining soil during excavation, the relative position between foundation pit and existing structure, the excavation depth, the existing structure rigidity. Furthermore, based on the analysis of difficulties in the T-shape expansion projects, the controlling measures for the deformation of existing metro station are proposed. The achievements of this case study can be used as a reference for similar underground expansion projects.

Passengers’ experience in underground non-transfer metro stations: The impact of spatial characteristics

Underground spaces have emerged as a promising solution for enhancing the overall quality of life in cities by allowing for better land use, reducing noise, and improving air quality. However, the subterranean placement of non-infrastructure facilities gives rise to numerous apprehensions, predominantly concerning the experience of their users. The underground environment may evoke fears and anxieties, disrupt cognitive and physiological responses, and affect personal safety. This paper examines the extent to which the specific spatial characteristics of underground non-transfer metro stations influence the passenger experience measured by the subjective indicators of comfort and safety. The research combines survey data collected from 1400 users with spatial data obtained from space syntax analyses and field investigations of 28 underground metro stations in Warsaw, Poland. Based on the results of multiple regression analysis, a set of spatial features that affect user comfort and safety was identified. The results show that passengers’ experience is shaped by several architectural characteristics of metro ‘stations, as well as their accessibility and position in the city and neighbourhood. Among the most influential architectural features is the configuration of the concourse level followed by the geometry of the platform hall and the use of art elements. Based on the findings presented in the study, potential design strategies that could improve the user experience are proposed and discussed. The recommended approaches offer valuable insights for designers aiming to improve the existing metro stations and facilitate more effective designs for new underground facilities.

Analyzing the Effect of Yellow Safety Line Designs at the Platform Edge in Metro Stations: An Experimental Approach

The objective of this paper was to analyze the effect of yellow-safety-line designs on the behavior of passengers at the platform edge in metro stations. To achieve this, an experimental approach, based on observation, was used in existing metro stations in Santiago and Valparaiso, Chile. The experiments were carried out for different widths of the yellow safety line: 5 cm, 10 cm, 24 cm, and 40 cm. In addition, the material was also changed to include yellow adhesive tape, PVC material with yellow pods, and carbon- and fiberglass-reinforced material with yellow pods. The experiments considered a mock-up to represent the hall entrance of the train and its adjacent platform, in which 25 participants were recruited, some of whom had reduced mobility. The results obtained from the experiments showed that the greater the width of the yellow safety line at the edge of the platform, the greater the level of compliance that was achieved. In addition, surveys were carried out with the passengers who participated in the experiment; the majority felt more comfortable and safer for a width of 24 cm. Some participants highlighted the phenomenon of “safety offers comfort”. In conclusion, the results of this research will allow the generation of new design and safety standards for the train–platform interface, which can then be tested in existing stations. Future research is expected to study the space occupied by different types of passengers and to study accessibility in other circulation spaces of metro stations.

When and Where Do Home Values Increase in Response to Planned Light Rail Construction?

This paper examines the effects of an investment in light rail transit on single-family property values in Montgomery County, Maryland, with a focus on when and where such capitalization takes place and with intent to inform efforts to promote equitable transit-oriented development. We employ both hedonic price and repeat-sales estimation techniques to assure the results are robust. The findings indicate that housing prices, after the light rail transit went into the engineering phase, rose with proximity to anticipated new rail stations but not with proximity to existing metro stations. For planners and policymakers and advocates in Montgomery County, the results provide critical information about where and when value capture and anti-displacement policies are most needed and potentially effective.

A New Combined Support Technology to Prevent the Failure of the Existing Metro Station Induced by Unilateral Excavation

This study establishes a 3-D simulation model based on a real project, which reveals the problem that the metro structure deformation induced by unilateral excavation without any support exceeds the safety threshold. According to the metro structure deformation warning area, this study proposes a support technology that combines cover plate braces and diagonal steel braces. The research shows that the lateral deformation reduction ratio of the metro station under the diagonal steel brace is about 10% – 20%. The deformation reduction ratio under the cover plate brace is about 35% – 40%. To ensure construction safety, this study adopts the optimal support combination of 3 cover plates and 6+9+11 steel pipes. Monitoring feedback and simulation prediction shows that the comprehensive support system can reduce structural deformation by 56.1%, and effectively control the deformation within a safe range.

Cutting depth of pile materials subjected to the abrasive waterjet and its prediction model

Very limited study is available on the use of the abrasive waterjet in cutting the civil engineering structures such as the piles as compared to the use in rocks or metal. In this study pre-cutting of the reinforced concrete (RC) retaining piles by the abrasive waterjet is proposed to guarantee the operation of both the existing station and shield tunnel. The shield tunnel of Shenyang Metro Line 4 which has to underpass the existing metro station and needs to cut 37 RC retaining piles is taken into consideration in this study. Experiments of reinforced pile materials (i.e., rebar and concrete) subjected to the abrasive waterjet are carried out, which indicates that the cutting depth of the rebar increases with the decrease of the traverse speed. When the standoff distance (SOD) is within 30 mm, the effect of SOD on the cutting depth of the rebar can be ignored. However, when SOD is in the range of 30–100 mm, the cutting depth of the rebar decreases dramatically with the increase of SOD; when SOD is beyond 300 mm, abrasive particles are ineffective in cutting. The cutting behaviour of the concrete is heavily dependent on the coarse aggregate on its cutting path. Finally, the prediction model of the cutting depth of the rebar is proposed, which helps the determination of the optimal cutting number and provides some theoretical basis for the construction of shield tunnelling when encountering RC piles.

Deformation characteristics and failure evolution process of the existing metro station under unilateral deep excavation

With the rapid development of underground space construction, there are more and more large-scale deep foundation pit projects on one side of the metro station. Unilateral deep excavation will result in an imbalance of the earth pressure on both sides of the existing metro station, which is a major engineering risk. Therefore, considering the station width and the excavation depth, this study focuses on the deformation characteristics and failure evolution process of the existing metro station structure caused by unilateral excavation based on the physical model test and discrete element method (DEM) analysis. This research shows that the lateral deformation of the top of the station caused by unilateral excavation is the most significant. Secondly, as the excavation depth increases and the station width decreases, the increase rate of the station overall inclination and lateral displacement becomes more significant. Thirdly, the structure fails when the excavation depth is 5/6H (H is the station height). Then the station instability leads to three disturbed regions in the adjacent stratum. The contact force between soil particles in the disturbed region is small and the stability is poor. Finally, the failure evolution process of the existing station under unilateral excavation is divided into three stages: (a) when the excavation depth is 0–1/2H, the soil and structure are stable; (b) when the excavation depth is 1/2–3/4H, the lateral deformation and inclination of the station reach the security warning range; (c) when the excavation depth is 3/4–1.0H, the structure is unstable and slips laterally, resulting in the ground collapse and local soil extrusion failure. This study reveals the risks of the existing station at different excavation stages, which can make risk prediction for the construction of the project.

Numerical Analysis of the Influence of Foundation Pit Blasting on a Nearby Metro Tunnel

It is important to guarantee the safety of adjacent underground structures during the foundation pit blasting excavation of modern city construction. The blasting excavation construction of a large, deep foundation pit near an existing metro station of Guangzhou Metro Line 3 is used as the example in this study. Based on blasting vibration field test results, the influence of blasting dynamic load on the lining of an adjacent metro tunnel is numerically analyzed in simulation using Fast Lagrangian Analysis of Continua 3D (FLAC3D), and the relationships between the blasting vibration velocity and stress and the displacement of the metro tunnel lining are obtained. The results show that the stress of lining structure is within the allowable range under the experimental blasting conditions, the lining displacement increases linearly with the applied dynamic vibration velocity, and the vertical displacement of the lining is more obviously affected than the horizontal displacement by the dynamic load. This study can be used as a basis for the control of blasting vibration in a complex urban environment. Its practical application shows that the proposed blasting plan and parameters are reasonable and effective.

Built-in metro system concourse in historical buildings: the experience of Leningrad and Prague, modern problems and technologies in the context of a barrier-free environment establishment

Currently, the barrier-free environment establishment in transport (including in the metro system) is one of the most urgent tasks. When retrofitting existing metro stations for access by disabled people and other people with limited mobility in a dense urban development of the historical center, it will inevitably arise the need to build additional concourse and related premises in historical buildings and cultural heritage sites. For St. Petersburg, this topic is especially important, given the specific structure of the city’s historical center and the location peculiarities of central metro stations. This article examines and briefly analyzes the building metro concourse experience in historical buildings and cultural heritage sites in Leningrad (on the example of the St. Petersburg metro stations «Mayakovskva», «Nevsky Prospekt» / «Gostiny Dvor») and Prague (on the example of the Prague metro stations «I.P. Pavlova» and «Karlovo namesti»). The investigated Prague projects experience is the most relevant in relation to the modern providing a barrier-free environment challenges that St. Petersburg metro faced. The article also provides a cementing overview (for stabilizing the preserved object’s soil and foundations, including Jet Grouting) and their use peculiarities in the existing historical development. One of the options proposed by the authors to provide access for disabled people and other people with limited mobility to the Ploschad Vosstaniya metro station is considered. This option was prepared in the course of pre-design studies on organizing access for disabled people and other people with limited mobility to 11 Kirovsko-Vyborgskaya line stations of the St. Petersburg metro in 2019–2020.

Is Labour Productivity Higher in Transit Oriented Development Areas? A Study of Beijing

AbstractTransit oriented development (TOD) advocates enhancing public transport connectivity, clustering urban development around public transport nodes and creating station areas with high‐density, diverse land uses and pedestrian‐ and cycling‐friendly environments. While this urban development approach is expected to have positive effects on the urban economy, the impacts of TOD strategies on economic efficiency are yet to be empirically examined. This study operationalised economic efficiency as labour productivity; developed a methodology to investigate how labour productivity is distributed at the local level, to explore the relationships between TOD characteristics and the clustering of labour productivities across different types of industries within a city; and applied it to the case of Beijing, China. The results show that in most cases the distribution of labour productivity has no significant association with TOD characteristics. However, in certain consumer‐service‐related economic sectors (i.e. wholesale and retail; accommodation and catering; and culture, sports, and entertainment) labour productivity is on average significantly higher in an area with stronger transit‐oriented development characteristics. Furthermore, within the conceptual framework of agglomeration economies, the paper identified specific TOD characteristics that are related to the clustering of the higher level of labour productivities in certain industry sectors. These outcomes provide insights for developing more focused TOD strategies, aimed at enhancing the clustering of labour productivities in the identified industries around the existing metro station areas in Beijing.

Application of settlement monitoring of underground excavation station vault based on inverted rule method

In the urban rail transit engineering, there is a great risk in the underground excavation construction of the existing railway station, and the monitoring accuracy of the underground excavation construction is very high. Taking station A of a project as the research object, combined with the construction situation and the structural characteristics of the station, this paper discusses the influencing factors of the vault settlement monitoring in the undercut section of the existing metro station, and formulates the vault settlement monitoring scheme in the undercut section. The feasibility of the method is verified by setting up two sets of independent elevation system and adopting the method of setting up a single station to measure the inverted ruler, and then the error control measures are given. The results show that the method can meet the accuracy requirements of the vault settlement monitoring in the underground excavation section of metro station. This method can provide some technical reference for the similar monitoring project of underground subway station.

An Estimation Model on Electricity Consumption of New Metro Stations

Electricity consumption of metro stations increases sharply with expansion of a metro network and this has been a growing cause for concern. Based on relevant historical data from existing metro stations, this paper proposes a support vector regression (SVR) model to estimate daily electricity consumption of a newly constructed metro station. The model considers some major factors influencing the electricity consumption of metro station in terms of both the interior design scheme of a station (e.g., layout of the station and allocation of facilities) and external factors (e.g., passenger volume, air temperature and relative humidity). A genetic algorithm with five-fold cross-validation is used to optimize the hyper-parameters of the SVR model in order to improve its accuracy in estimating the electricity consumption of a metro station (ECMS). With the optimized hyper-parameters, results from case studies on the Beijing Subway showed that the estimating accuracy of the proposed SVR model could reach up to 95% and the correlation coefficient was 0.89. It was demonstrated that the proposed model could outperform the traditional methods which use a back-propagation neural network or multivariate linear regression. The method presented in this paper can be an adequate tool for estimating the ECMS and should further assist in the delivery of new, energy-efficient metro stations.

Evaluation of Relationships Between Ridership Demand and Transit-Oriented Development (TOD) Indicators Focused on Land Use Density, Diversity, and Accessibility: A Case Study of Existing Metro Stations in Bangkok

The purpose of this work is to support the transit-oriented development (TOD) in Thailand. The main research objective is to explore the relationship between ridership demand and TOD indicators, which is expected to be the first question that a developer in Thailand must be able to answer in order to direct their development plan in the right direction. Using existing Bangkok metro stations as a case study, 22 variables categorized into three groups (density, diversity, and design) were collected for an 800-m buffer area around the stations. Results of the correlation analysis between transit ridership and other variables show a significant relation with the volume of transit ridership. Bus services have a stronger influence on transit ridership than railway stations and ferries (pier). Also, the interchange stations and park-and-ride buildings are found to be the main variables that correlate directly with the transit ridership numbers. Results from the principal component analysis are used to evaluate factors of TOD characteristics for the existing Bangkok metro stations, categorized into seven factor groups.

Metro station naming strategies in selected megacities and lessons for new metro systems

There were 31 megacities in the world in 2016 and 10 more are expected to join the group by 2030. Most of the old megacities developed their Mass Rapid Transit systems many decades ago, while some of the aspiring megacities are in the process of building their MRT systems today. Building infrastructure is just one aspect of the system, while naming stations is another. This study analysed metro station names in seven selected megacities across five continents in order to understand naming strategies better by looking at patters, rules and any other guidance that could be applied to stations being part of new systems. Results presented in the study reveal that the shortest station names in the sample are in Tokyo (on average 10 characters and 1.3 words) while the longest are in New York City (on average 16 characters and 2.6 words). Also, a closer look at metro maps shows that some systems apply bi-lingual station names with national and English languages used. In-depth analysis of the selected metro systems allowed to identify key drivers for station naming strategies, which often are unique to a system and deeply rooted in a local context. For example, in New York City and Bangkok street-based names are most popular (89% vs. 41%) while in Sao Paulo, Cairo and London an area name is a dominant station name category (53% vs. 33% vs. 24+%). Person’s names are quite popular as station names in Cairo (26%) and Sao Paulo (20%). Organisations’ names however are not that common, although some systems allow for example university-based names, such as Helwan University (Cairo) or 116 Street-Colombia University (New York City). In addition, New York City, Cairo and Delhi metro systems allow station naming rights to be purchased by a private company, but a scale of this phenomenon and their rules differ. Results presented in the paper review existing metro station naming strategies and provide lessons for new or under construction metro systems. Recommendations include a set of steps which could be taken into account by megacities and other cities debating on best metro station naming strategies to be applied in their unique context.

The Analysis about Influence of Pile Foundation Construction on the Near Metro Tunnel

Based on the case of the construction of a bridge connecting engineering in Wuhan, this paper aims to make simulation analysis on the viaduct abutment pile foundation construction process which is close to the metro station, and find out the influence of deformation of pile foundation construction on existing metro stations. The results show that: Bridge piles near the subway station will have some distortion, but the deformation in each direction is within the safe range. Considering the situation that No.5 Base is close to No. 1 duct, it is recommended that No.5 Base Foundation should use the protection measure of steel sheet pile enclosure construction during excavation to ensure the safety of the viaduct and bridge construction on piles near the subway tunnel.

Performance of a Deep Excavation and Its Effect on Adjacent Tunnels in Shanghai Soft Clay

AbstractA 267-m-long, 54-m-wide, and 14.9–16.4-m-deep multipropped deep excavation with three cross walls in Shanghai soft clay was constructed at a side of an existing metro station. To investigate the performance of this deep excavation and the effect of this deep excavation on adjacent metro station and shield tunnels, the ground deformation and structure responses were extensively monitored. Based on the field observations, the deflections and vertical movements of diaphragm walls, surface settlements, vertical and horizontal displacements of the up track and the down track within the station and nearby shield tunnels, as well as tunnel convergence were extensively analyzed. By adopting cross walls, jet grouting and large dimension concrete struts, the measured maximum lateral wall deflection and ground deformation were much smaller than those at other sites without installing cross walls in Shanghai soft clay. The maximum excavation-induced lateral wall movements and ground settlement behind the reta...

Structural Responses of Existing Metro Stations to Adjacent Deep Excavations in Suzhou, China

Situations in which deep excavations are made adjacent to metro stations in service are common in the development of underground space. However, the structural responses of existing metro stations to adjacent deep excavations and their safety criteria are still not fully understood. Through a series of numerical parametric studies and comparisons with case histories reported in the literature, this paper examines both the structural forces and differential displacements of existing metro stations induced by adjacent excavations. To consider the effect of stress history, the hardening soil small-strain model (HSS) was employed, and the building process of existing metro stations was included in the numerical simulations. The effects of key factors, e.g., the distance between existing metro stations and new excavations and the depth of new excavations, governing the responses of existing metro stations to adjacent excavations are investigated and quantified. In addition, the barrier effects of existing metro stations on the deformations of adjacent excavations are also investigated. On the basis of the numerical analysis results, some major findings were obtained: (1) excavation depth, He, and distance from the existing metro station, D, were the key factors affecting the structural responses of an existing metro station to the adjacent excavation; (2) the rotation and shear effects of an existing metro station induced by the adjacent excavation varied with D/He and could be reversed in direction; (3) the bending moments in critical sections changed with D/He and the additional bending moments in the sections had a linear relationship with the rigid column rotations; and (4) because of the barrier effect of the metro station, both lateral wall deflections and ground surface settlements induced by the adjacent excavation on the side of the metro station were smaller than those without a metro station nearby. The findings yielded from this study should provide practically useful references for engineers to assess the structural performance and rail safety of existing metro stations affected by adjacent excavations so that appropriate countermeasures can be adopted.

Zoned Excavation of an Oversized Pit Close to an Existing Metro Line in Stiff Clay: Case Study

AbstractBecause greenfields available for new developments in congested urban areas are scarce in China, more and more excavations for building basements or other underground facilities (e.g., new metro lines, underground shopping malls, parking garages) have to be carried out in the close proximity of existing metro lines. To ensure project safety, it is essential to know potential adverse effects of excavations on adjacent metro lines in service. Until now, many studies have contributed to the cases of excavations overlying existing tunnels. In contrast, only a few were known for excavations parallel to adjacent existing tunnels. With regard to the responses of existing metro stations to adjacent excavations, few case studies were reported in the literature. Through an extensive field instrumentation program in combination of numerical simulations, this study examines the performance of an oversized deep excavation in stiff clayey deposits and the corresponding responses of the adjacent metro station an...

Metro Station Deformation Caused by Deep Foundation Pit Construction

Many excavation and backfill methods can be used to construct a deep foundation pit, but foundation pit construction will undoubtedly affects security of existing metro station. This research based on a transfer station of Chengdu Metro, three-dimensional numerical simulation method was used to analyze the deformation of metro station by changing construction methods of foundation pit. The results show that: (1) Both excavation and backfill methods of foundation pit have a significant effect on connection segments of metro station. (2) The main body of metro station is largely unaffected by foundation pit construction but it has been in the process of subsidence. (3) The more the construction steps of foundation pit are, the more slowly the displacement of metro station changes. The above results certainly contribute to research and develop new types of construction methods for complicated metro station.

Safety Analysis on the Structure of an Existing Metro Station Impacted by the Construction of an Adjacent Building

Structural deformations of the existing metro station caused by adjacent building construction should be controlled strictly so as to keep the normal operation of the existing metro station and guarantee the safety of the station structure. Based on a foundation pit excavation and building project which is adjacent to an existing metro station in Beijing, a 3D finite element model of foundation pit, metro station and surrounding soil is established. Then, the structural deformations of the main body structure (rail area), the passageway and the fire fighting passageway in different construction stages are obtained. The control values of the station structure deformation during building construction process are proposed according to the calculation results.