Functional Characteristics of Beijing Subway Stations Based on POI Data:Taking Beijing Metro Line 6 as An Example

Urban subway station is a key node related to urban social,political,economic and cultural activities.There are some differences in the location,function orientation,land use and flow characteristics of different types of stations in the city.This paper mainly used Tyson’s edge,kernel density analysis,chart analysis and other methods to classify the functional types of 412,393 POI data of 26 stations along Metro he results showed that the spatial distribution of Beijing Metro Line 6 was mainly divided into 3 categories,subway stations were divided into 4 categories.Among them,type A sites were divided into composite and single types,and the distribution characteristics of the 6 types of sites were quite different.Based on the qualitative and quantitative analysis of POI point data,this method can quickly classify and analyze the characteristics of stations along Line 6 in Beijing,which also has theoretical and practical value for the planning of urban subway lines.

A practical framework for performance-based reliability analysis of subway stations based on a faultestructure combined system

It is necessary to pay particular attention to the uncertainties that exist in an engineering problem to reduce the risk of seismic damage of infrastructures against natural hazards.Moreover,certain structural performance levels should be satisfied during strong earthquakes.However,these performance levels have been only well described for aboveground structures.This study investigates the main uncertainties involved in the performance-based seismic analysis of a multi-story subway station.More than 100 pulse-like and no pulse-like ground motions have been selected.In this regard,an effective framework is presented,based on a set of nonlinear static and dynamic analyses performed by OpenSees code.The probabilistic seismic demand models for computing the free-field shear strain of soil and racking ratio of structure are proposed.These models result in less variability compared with existing relations,and make it possible to evaluate a wider range of uncertainties through reliability analysis in Rtx software using the Monte Carlo sampling method.This work is performed for three different structural performance levels(denoted as PL1ePL3).It is demonstrated that the error terms related to the magnitude and location of earthquake excitations and also the corresponding attenuation relationships have been the most important parameters.Therefore,using a faultestructure model would be inevitable for the reliability analysis of subway stations.It is found that the higher performance level(i.e.PL3)has more sensitivity to random variables than the others.In this condition,the pulse-like ground motions have a major contribution to the vulnerability of subway stations.

Passengers gathering-scattering analysis at the corners of subway stations

During both daily operation and emergency evacuation,the corners of walking facilities in subway stations play an important role in efficient circulation.However,the effectiveness of the corner is difficult to assess.In this paper,a method of passenger gathering and scattering analysis based on queueing models was proposed to investigate the corner performance in subway stations.Firstly,we constructed a set of state spaces of passenger flow according to passenger density and proposed the state transition model of passenger flow.Moreover,the model of passenger flow blocking and unblocking probability were also presented.Then,to illustrate the validity of the method and model,several passenger gathering-scattering scenarios and were simulated to verify the influence of passenger distribution and facility width on passenger walking,and the blocking probability,throughput,and expected time were also analyzed under various widths of the target corridor and arrival rates.Results showed that the proposed model can reproduce the trend of walking parameters changing and the self-organizing phenomenon of'faster is lower'.With the increase of arrival rates of passengers,walking speeds of passengers decrease and the expected walking time is prolonged,and the blocking probability sharply increased when the arrival rate exceeded 7 peds/s.In addition,with change of width of the target facility,efficiency of capacity of walking circulation facility fluctuated.With the width of the target corridor enlarged by 10%,the steady state of passenger flow was less crowded.Therefore,corridor width is critical to the circulation efficiency of passengers in subway stations.The conclusions will help to develop reasonable passenger flow control plans to ease the jam and keep passengers walking safely.

Study on the Principle Model and Simplification of Subway Station Itemized Energy Consumption

Owing to the constant modernization and urbanization of China,most cities have subways,and the total power consumption of subway stations has been rising,which contradicts with China’s green goals.In this regard,energy consumption indicators for major energy use projects in subway stations should be established,comprehensive evaluation and detailed research on the current situation of subway operation should be conducted,and specific energy-saving measures should be taken from a diversified perspective.It is crucial to systematically sort out the principle of sub-item energy consumption in subway stations,and practice and explore the specific simplification measures of the principle model of sub-item energy consumption,so as to lay a solid foundation for achieving the goal of reducing energy consumption of subway stations.

Pedestrian evacuation at the subway station under fire

With the development of urban rail transit, ensuring the safe evacuation of pedestrians at subway stations has become an important issue in the case of an emergency such as a fire. This paper chooses the platform of line 4 at the Beijing Xu- anwumen subway station to study the emergency evacuation process under fire. Based on the established platform, effects of the fire dynamics, different initial pedestrian densities, and positions of fire on evacuation are investigated. According to simulation results, it is found that the fire increases the air temperature and the smoke density, and decreases pedestrians＇- visibility and walking velocity. Also, there is a critical initial density at the platform if achieving a safe evacuation within the required 6 minutes. Furthermore, different positions of fire set in this paper have little difference on crowd evacuation if the fire is not large enough. The suggestions provided in this paper are helpful for the subway operators to prevent major casualties.

Seismic performance of a rectangular subway station with earth retaining system

Much effort has been made in investigating the seismic response and failure mechanism of rectangular subway stations,however,the influence of earth retaining systems has generally been ignored in previous studies.This paper presents a numerical study on the seismic performance of a rectangular subway station with/without earth retaining systems by taking fender piles as the example,and aims to illustrate how the existence of fender piles affects seismic responses on subway stations.The loading conditions of subway stations and their surrounding soils prior to earthquakes are discussed.Next,seismic responses of subway stations with or without fender piles were simulated.Afterward,earthquake-induced deformations of stations and surrounding soils,as well as the internal forces and damage modes of the structural components,were systematically studied.Consequently,the seismic performance of the stations was affected by the existence of fender piles.In addition,earthquake intensity is illustrated.The study showed that deformation modes of surrounding soils and damage modes of stations were different with regard to the existence of fender piles.Meanwhile,earthquake intensity influencing the seismic performance of stations with or without fender piles were found to be opposite.

Passenger management strategy and evacuation in subway station under Covid-19

Under the background of Covid-19 sweeping the world,safe and reasonable passenger flow management strategy in subway stations is an effective means to prevent the spread of virus.Based on the social force model and the minimum cost model,the movement and path selection behavior of passengers in the subway station are modeled,and a strategy for passenger flow management to maintain a safe social distance is put forward.Take Qingdao Jinggangshan Road subway station of China as the simulation scene,the validity of the simulation model is verified by comparing the measured value and simulation value of the time required for passengers from getting off the train to the ticket gate.Simulation results indicate that controlling the time interval between incoming passengers at the entrance can effectively control the social distance between passengers and reduce the risk of epidemic infection.By comparing the evacuation process of passengers under different initial densities,it is found that the greater the initial density of passengers is,the longer the passengers are at risk social distance.In the process of passenger emergency evacuation,the stairs/escalators and ticket gates are bottleneck areas with high concentration of passenger density,which should be strictly disinfected many times on the basis of strictly checking the health code of incoming passengers and controlling the arrival time interval.The simulation results of this paper verify the harmfulness of passenger emergency evacuation without protective measures,and provide theoretical support for the operation and management of subway station under the epidemic situation.

Thermal comfort evaluation of people in subway station

We analyzed the characteristics of subway station environment and the change of thermal comfort for passengers when they are in and out of the station. The dynamic thermal comfort evaluation model RWI(relative warmth index) and HDR(heat deficit rate) were built on the distinguishing features of public area in subway station. Taking one representative subway station in Nanjing as the research object, the thermal comfort conditions in different seasons and different parts were studied by field tests, questionnaires and model-evaluating. The calculated RWI shows that although the thermal comfort in Nanjing metro is relatively acceptable, ideal thermal comfort has not been achieved. And it is found that associated with predicted mean vote(PMV), using RWI can evaluate the thermal comfort more precisely.

Numerical Simulation and Field Monitoring Analysis for Deep Foundation Pit Construction of Subway Station

To investigate the effect of deep foundation pit excavation on the stability of retaining structure, a subway stationin the city of Jinan was selected as a project, and a FLAC3D-based three dimensional model was developed fornumerical simulation. The horizontal displacement of the retaining structure, the axial force of the support, andthe vertical displacement of the column were studied and compared to the collected data from the field. The findingsindicate that when the foundation pit is excavated, the maximum deformation of the retaining structure progressivelydecreases from the top, the distortion of the retaining structure gradually rises, and the final maximumdeformation is around 17 meters deep. In each layer of support, the largest axial force support is located in thefirst reinforced concrete support;the uplift of the pit bottom caused by soil unloading plays a primary role in thevertical displacement of the column, and the column exhibits an upward trend under all construction conditions.When compared to the measured data, the generated findings are comparable and the fluctuation trend is extremelyconsistent. The findings of this article may give technical direction for the development of subway stationswith a comparable engineering basis.

Feasibility evaluation for excavation of Naghshe Jahan Square subway station by underground methods

In recent years, in reaction to the increasing usage of urban areas, the excavation of underground spaces has been developed. One of the most challenging issues encountered by engineers is the construction of subway stations as large underground spaces at shallow depth with soft surrounding soils. In this paper, Naghshe Jahan Square subway station located in Isfahan, Iran, has been simulated by geomechanical fnite difference method(FDM). This station is located under important historical structures. Therefore, the ground displacement and surface settlement induced by the excavation of the subway station should be strictly controlled. Many of such problems are affected by selected excavation method. For these reasons, different underground excavation methods associated with construction have been studied. In this study, sequential excavation method and large-diameter curved pipe roofng method are used and the numerical results of the two methods are compared. The presence of groundwater table obliges us to choose special techniques for the stability of the ground around the subway station during construction; hence compressed air and ground freezing techniques are utilized in the simulations of the subway station. Finally, after choosing appropriate support systems, the large-diameter curved pipe roofng method with 1.5 m spacing between curved pipes is proposed.

Seismic performance of two-story subway station structures with different isolating systems

When the sliding bearing is fixed only at the top of the middle column of the underground structure,the cracks at the side end of the middle plate should be aggravated while the seismic damage of the mid-column should be alleviated.To enhance the seismic performance of the mid-plate,a new isolation design method has been mentioned while the elastic sliding bearings are set at the top of the mid-columns and between the side end of the mid-plate and the side wall at the same time.By establishing a nonlinear finite element analysis model for the static-dynamic coupling interaction system,the seismic response characteristics of the cast-in-place station structure without a sliding bearing have been analyzed and compared with those of the station structure with the sliding bearing fixed only at the top of the middle columns,and those of the station structure with sliding bearing be fixed between the mid-plate and the sidewall at the same time.The results show that the new isolation station structures suffer fewer earthquake damages at the mid-plate and mid-columns at the same time,which can improve the overall seismic performance of the subway station structure.

Artistic Space Design of Subway Station Based on Regional Characteristics

On the basis of existing problems in the spatial design of subway station, this paper explored the principles that regional culture involves in the artistic space design of subway station; based on the analysis of three main design sections and site cases-spatial interface, public art and color, the paper also discussed the artistic application and design embodiment of regional culture characteristics reflected in every element of subway station space design, so as to provide a consolidated design example for subway station space design featuring regional characteristics in the future.

Simulation of fire emergency evacuation in a large-passenger-flow subway station based on the on-site measured data of Shenzhen Metro

Because of its large capacity,high efficiency and energy savings,the subway has gradually become the primary mode of transportation for citizens.A high density of passengers exists within a large-passenger-flow subway station,and the number of casualties and injuries during a fire emergency is substantial.In this paper,Pathfinder software and on-site measured data of Pingzhou station in Shenzhen(China)were utilized to simulate a fire emergency evacuation in a large-passenger-flow subway station.The Required Safe Egress Time(RSET),number of passengers and flow rates of stairs and escalators were analysed for three fire evacuation scenarios:train fire,platform fire and hall fire.The evacuation time of the train fire,which was 1173 s,was the longest,and 3621 occupants needed to evacuate when the train was fully loaded.Occupants could not complete the evacuation within 6 mins in all three fire evacuation scenarios,which does not meet the current standard requirements and codes.By changing the number of passengers and the number of stairs for evacuation,the flow rate capacity and evacuation time were explored,which have reference values for safety management and emergency evacuation plan optimization during peak hours of subway operation.

Nonparametric probabilistic seismic demand model and fragility analysis of subway stations using deep learning techniques

A novel and computationally efficient method for developing a nonparametric probabilistic seismic demand model(PSDM)is pro-posed to conduct the fragility analysis of subway stations accurately and efficiently.The probability density evolution method(PDEM)is used to calculate the evolutionary probability density function of demand measure(DM)without resort to any assumptions of the dis-tribution pattern of DM.To reduce the computational cost of a large amount of nonlinear time history analyses(NLTHAs)in the PDEM,the one-dimensional convolutional neural network(1D-CNN)is used as a surrogate model to predict the time history of struc-tural seismic responses in a data-driven fashion.The proposed nonparametric PSDM is adopted to conduct the fragility analysis of a two-story and three-span subway station,and the results are compared with those from two existing parametric PSDMs,i.e.,two-parameter lognormal distribution model and probabilistic neural network(PNN)-based PSDM.The results show that the PDEM-based PSDM has the best performance in describing the probability distribution of seismic responses of underground structures.Differ-ent from the fragility curves,the time-dependent fragility surface of the subway station shows how the exceedance probability of damage state changes over time.It can be used to estimate the escape time and thus the number of casualties in an earthquake,which are impor-tant indexes when conducting the resilience-based seismic evaluation.

Numerical study on the seismic response of the underground subway station-surrounding soil mass-ground adjacent building system

Ground buildings constructed above metro station have increased very quickly due to the limited land resources in urban areas. In this paper, the seismic response of the Underground subway station-Surrounding soil mass- Ground adjacent buildings （USG） system subjected to various seismic loading is studied through numerical analysis. The numerical model is established in terms of the calculation domain, boundary condition, and contact property between soil and structure based on the real project. The reciprocal influence between subway station and ground adjacent building, and their effects on the dynamic characteristics of surrounding soil mass are also investigated. Through the numerical study, it is found that the impact of underground structure on the dynamic characteristics of the surrounding soil mass depends on its own dimension, and the presence of underground structure has certain impact on the seismic response of ground adjacent building. Due to the presence of underground structure and ground adjacent building, the vertical acceleration generated by the USG system cannot be ignored. The outcomes of this study can provide references for seismic design of structures in the USG system.

A study on bearing characteristic and failure mechanism of thin-walled structure of a prefabricated subway station

In order to study the bearing performance of a new type of prefabricated subway station structure(PSSS),firstly,a three-dimensional finite element model of the PSSS was established to study the nonlinear mechanics and deformation performance.Secondly,the bearing mechanism of a PSSS was investigated in detail.Finally,the development law of damages to a thin-walled prefabricated component and the failure evolution mechanism of a PSSS were discussed.The results showed that this new type of the PSSS had good bearing capacity.The top arch structure was a three-hinged arch bearing system,and the enclosure structure and the substructure were respectively used as the horizontal and vertical support systems of the three-hinged arch structure to ensure the integrity and stability of the overall structure.Moreover,the tongue-and-groove joints could effectively transmit the internal force between the components and keep the components deformed in harmony.The rigidity degradation of the PSSS caused by the accumulation of damages to the spandrel,hance,arch foot,and enclosure structure was the main reason of its loss of bearing capacity.The existing thin-walled components design had significant advantages in weight reduction,concrete temperature control,components hoisting,transportation and assembly construction,which achieved a good balance between safety,usability and economy.

Comparison of shallow tunneling method with pile and rib method for construction of subway station in soft ground

In the present study,a comparison between the new shallow tunneling method(STM)and the traditional pile and rib method(PRM)was conducted to excavate and construct subway stations in the geological conditions of Tehran.First,by selecting Station Z6 located in the Tehran Subway Line 6 as a case study,the construction process was analyzed by PRM.The maximum ground settlement of 29.84 mm obtained from this method was related to the station axis,and it was within the allowable settlement limit of 30 mm.The acceptable agreement between the results of numerical modeling and instrumentation data indicated the confirmation and accuracy of the excavation and construction process of Station Z6 by PRM.In the next stage,based on the numerical model validated by instrumentation data,the value of the ground surface settlement was investigated during the station excavation and construction by STM.The results obtained from STM showed a significant reduction in the ground surface settlement compared to PRM.The maximum settlement obtained from STM was 6.09 mm as related to the front of the excavation face.Also,the sensitivity analysis results denoted that in addition to controlling the surface settlement by STM,it is possible to optimize some critical geometric parameters of the support system during the station excavation and construction.

Case study on the seismic response of a subway station combined with a flyover

With the rapid development of urban traffic networks,subway stations will inevitably be constructed close to other structures in the future.The subject of this study is a new subway station in China,combined with a flyover standing on the roof,owing to its unique structural design.Based on the time history-analysis method,the dynamic responses of the subway station,piers,and piles under seismic conditions were examined.The results show that the internal force and deformation of the underground structure vary under seismic excitation in different directions and are more dangerous in the under transverse excitation than under longitudinal excitation.Moreover,the dynamic response of the underground structure is severe under the action of low-frequency-rich Wenchuan waves,and the resonance effect is distinct.The load of the bridge was found to inhibit the deformation of the underground structure to a certain extent.Furthermore,the mid-pillar and slab-mid-pillar connections are the weakest parts,and special attention should be paid to their seismic design.Meanwhile,the piers and piles can maintain good working condition under the action of an earthquake with the peak acceleration of 0.1g.

Optimization Scheme of Large Passenger Flow in Huoying Station,Line 13 of Beijing Subway System

This paper focuses on the distribution of passenger flow in Huoying Station,Line 13 of Beijing subway system.The transformation measures taken by Line 13 since operation are firstly summarized.Then the authors elaborate the facilities and equipment of this station,especially the node layout and passenger flow field.An optimization scheme is proposed to rapidly distribute the passenger flow in Huoying Station by adjusting the operation time of the escalator in the direction of Xizhimen.The authors adopt Queuing theory and Anylogic simulation software to simulate the original and the optimized schemes of Huoying Station to distribute the passenger flow.The results of the simulation indicate that the optimized scheme could effectively alleviate the traffic congestion in the hall of Huoying Station,and the pedestrian density in other places of the hall is lowered;passengers could move freely in the hall and no new congestion points would form.The rationality of the scheme is thus proved.

Analysis and Discussion on Subway Construction Accidents from Geological Perspective

Several cave-in accidents often occur in subway construction,causing personnel and economic losses.This paper has carried on the statistics and analysis of some typical subway construction accidents in recent years.Taking the collapse accident of a subway station in Hangzhou as the engineering background,the causes of the collapse of the foundation pit were analyzed.The analysis found that groundwater,earthwork over-excavation,weak support design and inadequate monitoring are the main reasons.These factors should be highlighted in the construction of similar projects in the future to avoid similar tragedies.