Urban Underground Research Articles

Modeling Resilience of Metro-Based Urban Underground Logistics System Based on Multi-Layer Interdependent Network

The metro-based underground logistics system (M-ULS) has been identified as an effective solution to urban problems resulting from the expansion of urban freight traffic. However, there is a paucity of current research that examines the resilience of a M-ULS in the context of unexpected events during operations. Therefore, this paper presents a methodology for assessing the resilience of the M-ULS. The method considers the propagation paths of various failures in a multi-layered, interdependent network that includes topology, functionality, facilities, and information, as well as network performance indicators based on network freight flow and logistics timeliness. The effectiveness of the method is demonstrated using the case of the Nanjing Metro. The results show that the type of disruption, the duration, and the direction of train travel all have a significant impact on the resilience of the M-ULS. The method proposed in this paper provides a scientific basis for the assessment and optimization of M-ULS resilience and also offers new insights into the use of urban rail transit to promote the sustainable development of urban logistics.

Discussion on Structural Health Monitoring of Urban Underground Road Tunnel

Discussion on Structural Health Monitoring of Urban Underground Road Tunnel

Green Roofs in Urban Underground Buildings: Design Impact on Perceptual Comfort

Green Roofs in Urban Underground Buildings: Design Impact on Perceptual Comfort

Key Factors in the Design of Urban Underground Metro Lines

Designing sustainable underground metro lines in dense urban environments is a highly challenging task that requires the collaboration of numerous stakeholders and consultants to make crucial decisions influenced by several factors. While it is impossible to address every issue influencing the decision-making process, identifying key factors and their interdependencies is essential for optimal design. This study focuses on six critical aspects of the reference design of metro systems: (1) track alignment, (2) tunneling strategy, (3) station typology, (4) operations and maintenance, (5) procurement strategy, and (6) environmental aspects. Amongst these aspects, we identify track alignment as the primary driving factor that influences the other factors. We analyze the decision between shallow and deep alignments as an engineering choice that necessitates balancing conflicting factors and constraints. Our contribution lies in mapping these factors and their dependencies, thus offering policymakers, project managers, and designers a framework to navigate the design process. Our discussion also provides guidance to public agencies in tendering for design teams more efficiently. Drawing from lessons learned by experienced design managers, this study aims to fill the gap in the literature by offering a generalist perspective on metro design.

Assessment of Energy Recovery Potential in Urban Underground Utility Tunnels: A Case Study

Underground spaces contain abundant geothermal energy, which can be recovered for building ventilation, reducing energy consumption. However, current research lacks a comprehensive quantitative assessment of its energy recovery. This research evaluates the energy recovery potential of the Xingfu Forest Belt Urban Underground Utility Tunnels. Field experiments revealed a 7 °C temperature difference in winter and a 2.5 °C reduction during the summer-to-autumn transition. A computational fluid dynamics (CFD) model was developed to assess the impact of design and operational factors such as air exchange rates on outlet temperatures and heat exchange efficiency. The results indicate that at an air change rate of 0.5 h−1, the tunnel outlet temperature dropped by 10.5 °C. A 200 m tunnel transferred 8.7 × 1010 J of heat over 30 days, and a 6 m × 6 m cross-sectional area achieved 1.1 × 1011 J of total heat transfer. Increasing the air exchange rate and cross-sectional area reduces the inlet–outlet temperature difference while enhancing heat transfer capacity. However, the optimal buried depth should not exceed 8 m due to cost and safety considerations. This study demonstrates the potential of shallow geothermal energy as an eco-friendly and efficient solution for enhancing building ventilation systems.

Resilience quantification and recovery strategy simulation for urban underground logistics systems under node and link attacks: A case study of Nanjing city

Urban Underground Logistics Systems (UULS) have become an emerging solution to mitigate urban surface traffic congestion, environmental pollution, and surface transport safety risks. However, during the operation of UULS, the use of advanced technologies such as the Internet of Things (IoT) introduces cybersecurity risks to the system. Moreover, severe natural disasters can also cause damage to underground transportation network links. Existing research and planning primarily concentrate on the system design and benefits of UULS, neglecting the system's service level under attack scenarios. This study outlines three representative UULS network prototypes and proposes a resilience quantification method centered on logistics efficiency. It also focuses on comparing the effectiveness of three recovery strategies. These strategies give priority to maximum flow, betweenness centrality, and regional importance, as well as the priority of node and link repairs. The resilience quantification method and recovery strategies are applied in a case study set in Nanjing City. The case study results reveal that the Two-echelon network shows exceptional resilience. Regarding the effectiveness of recovery strategies, the strategy based on maximum flow proves to be the most effective, and focusing on node repair can lead to higher system resilience. Based on these findings, this study offers recommendations to transportation and logistics management decision-makers, focusing on UULS resilience and recovery strategy selection. These recommendations are intended to provide valuable guidance for the planning and design of future UULS, ensuring their resilience and reliability.

Driving Behavior Characteristics of Merging Sections in the Urban Underground Road Junction: A Driving Simulator Study

Driving Behavior Characteristics of Merging Sections in the Urban Underground Road Junction: A Driving Simulator Study

A Study on How Urban Rail Operators Can Secure New Growth Engines for the Future Approach: The Case of Underground Urban Logistics System

A Study on How Urban Rail Operators Can Secure New Growth Engines for the Future Approach: The Case of Underground Urban Logistics System

Investigating the response of Urban Underground Utilities (3U) within an elastic and elastoplastic geological formation: Employing numerical and analytical techniques

Investigating the response of Urban Underground Utilities (3U) within an elastic and elastoplastic geological formation: Employing numerical and analytical techniques

Erratum to: Crack Detection of the Urban Underground Utility Tunnel Based on Residual Feature Pyramid Attention Network

Erratum to: Crack Detection of the Urban Underground Utility Tunnel Based on Residual Feature Pyramid Attention Network

Three-Dimensional Quality Assessment of Urban Underground Space Resource Based on Multiple Geological Environmental Factors

With the rapid advancement of urbanization, the development and utilization of urban underground space resource (UUSR) has become one of the dominant features. However, in certain areas, the development of UUSR may cause disasters and accidents, such as ground collapse, settlements, and tunnel water gushing. Geological environmental factors (GEFs) are recognized as the fundamental constraining factor of UUSR development. In this paper, quality based on GEFs is defined to assess the development difficulty degree of UUSR. A 3D assessment framework is proposed based on 3D geological modelling and the interval continuous mathematical model (ICMM). The subjective and objective joint weight method of analytic hierarchy process and entropy weight method (AHP–EWM) is utilized to determine the weight of each indicator. The quality index (QI) of each spatial node of the 3D geological model is calculated by the ICMM mathematical model. A case study conducted in the Jiangbei New District of Nanjing, China, serves as a demonstration of the UUSR assessment. The results clearly illustrate the 3D distribution characteristics of the quality in the study area, offering valuable insights for future 3D urban underground space planning.

Research on the Driving Factors and Prediction Model of Urban Underground Space Demand in China

The development and utilization of urban underground space (UUS) have emerged as critical strategies to address the challenges posed by urban population growth and land resource depletion. Accurate prediction of UUS demand serves as the cornerstone for scientifically planning underground space and promoting sustainable urban development. In this study, statistical analysis methods were used to investigate the relationship between potential driving factors and UUS demand based on collected data from 16 cities in China. The identification of primary driving factors involves correlation, path, and determination coefficient analyses. Subsequently, univariate regression, multiple linear regression, and LASSO regression methods are employed to construct prediction models for UUS demand. Additionally, the link between historical data and UUS demand in each city was studied separately. The findings reveal that GDP per km2 and GDP per capita comprehensively capture the influence of urban population, economy, and transportation on UUS demand. Notably, GDP per km2 makes the most significant contribution to the proposed regression models, followed by GDP per capita. The application of LASSO regression proves effective in selecting potential factors while maximizing data utilization, presenting itself as a valuable auxiliary tool for UUS planning.

Peculiarities of urban planning organization of underground research complexes

The relevance of the construction and operation of underground research facilities specializing in the fields of astrophysics, particle physics, geophysics and biology has developed significantly over the past 30 years. Underground research facilities are able to provide the necessary conditions for conducting experimental studies of physical phenomena that go beyond the Standard Model of Physics. Among the publications devoted to the theoretical foundations of the development of underground urbanism, it is worth noting the works of E. Reynolds, R. Sterling, W. Breuer, and G. Haiko. The main aspects of the architectural and planning and volumetric-spatial structure of underground buildings and structures are outlined in the works of H. Admiral, A. Cornaro, J. Besner. The exploitation of underground space in the conditions of sustainable development of modern cities is studied in the works of L. von der Tann and S. Ritter, Fang-Le Peng, Yong-Kang Xiao. Ukrainian scientists have made a significant contribution to the theoretical issues of underground urbanism: S.V. Ryndyuk, M.A. Maksymenko. Prospects for the integrated development of underground space in Ukraine are highlighted in the works of T.O. Nishchyk. Scientific works of G.I. Gayko are devoted to the priority tasks of development of underground urbanism in Ukraine, assessment of risks of underground construction, historical development of underground space in Ukraine. The historical development of underground buildings and structures is also studied in the works of V. Biletskyi, L. Korkushko, A. Pleshkanovska. The overview of the planning structure of modern underground research complexes is presented in the articles by A. Ianni, A. Bettini, E. Coccia. The article presents a number of prerequisites that influence the choice of a site for the design of underground research complexes in Ukraine. Their brief description is presented. Based on a preliminary analysis of the world experience in designing this type of facilities, important criteria that should be used when choosing a design site are identified. A complete set of functional zones of the master plan of the above-ground territory of the underground research complex is defined. A number of basic recommendations have been formulated that should guide the designer in the development of the master plan.

Crack Detection of the Urban Underground Utility Tunnel Based on Residual Feature Pyramid Attention Network

Crack Detection of the Urban Underground Utility Tunnel Based on Residual Feature Pyramid Attention Network

Demand Evaluation of Urban Underground Space through Geospatial Big Data

Demand Evaluation of Urban Underground Space through Geospatial Big Data

Application of OCTEM in The Detection of Hidden Faults in Urban Underground Space Investigation

At present, the geological survey of urban underground space is currently being carried out in many cities across the country. Choosing appropriate survey methods will make this work more effective. OCTEM is a new exploration method that has emerged in engineering geophysical prospecting in recent years. It has the advantages of portable facilities and strong anti-interference ability, and is suitable for urban geological survey work. In this paper, OCTEM is applied to the hidden fault detection work in underground space survey in Chengdu. The results show that this method can effectively identify the fault fracture zone in the strong interference urban environment. At the same time, the OCTEM results are compared with the application results of the other 2 geophysical methods. The analysis further proves the adaptability and superiority of this method. It provides an effective new method for urban underground space survey work.

Application of Horizontal-to-vertical Spectral Ratio with a Dense Linear Array on Prospecting Urban Underground Active Faults: a Case in The Mingguang City, Anhui Province

Reliable knowledge of sedimentary structures is beneficial for the study of active faults covered by sediments and can also provide important information for seismic hazard assessment, earthquake emergency response and urban planning. Based on the dense seismic array with a spacing of ∼ 60 m between stations and a length of ∼ 8 km, the horizontal-to-vertical spectral ratio (HVSR) curves were obtained at 133 stations with the ambient noise, and the two-dimensional sedimentary structures of the Quaternary and Neogene strata were imaged over two main faults of the Tanlu fault zone in the eastern Jiashan Basin by frequency-depth conversion. The variations (∼ 130 m) in the depth of the Quaternary and Neogene sedimentary basement directly beneath the fault zone agree well with the spatial characteristics of the fault revealed by the shallow seismic reflection profile with active sources at the same locations.

Experiment on Interference Factors of High-precision Gravity Detection in Urban Underground Space

The traditional geophysical methods in urban underground space detection suffer from many interference factors, and cannot obtain effective detection data. The high-precision gravity method has few interference factors. For human activities and other interference sources, reasonable research work arrangements can be made through preliminary experimental analysis, and these interference factors can be avoided in actual work to obtain effective gravity observation data and interpretation results. The author studies the theoretically affected factors in urban detection and conducts experimental detection and analysis. The high-precision gravity method has a good effect on the detection of urban underground space.

Research on the Fire Extinguishing Efficiency of Low-Pressure Water Mist in Urban Underground Utility Tunnel Cable Fires

Low-pressure water mist fire extinguishing systems are a cost-effective and highly reliable option for fire protection. However, they have not yet seen widespread use in urban underground utility tunnels. To validate the fire extinguishing effectiveness of the system in cable fires within urban utility tunnels and to identify the key factors influencing its efficiency, a scaled-down test platform for low-pressure water mist fire extinguishing in utility tunnels was constructed, and a series of fire extinguishing tests was conducted. The test results demonstrate that low-pressure water mist can rapidly and effectively extinguish cable fires in utility tunnels, with the quickest fire extinguishing time of 7 s. Within 50 s of activating the system, the internal temperature of the tunnel can be reduced from 650 °C to 40 °C. Among the influencing factors, the pressure and nozzle flow coefficient have a significant impact on the fire extinguishing efficiency, while nozzle spacing has a relatively smaller effect. Thus, when the nozzle spacing meets the requirement of “no dead zones”, priority should be given to increasing the pressure and nozzle flow coefficient.

Settlement Characteristics of Urban Underground Comprehensive Pipe Gallery under Different Backfill Conditions

In order to solve the problem of differential settlement of pavement after the backfilling of urban underground comprehensive pipe corridors based on a pipe gallery project in Xiong’an New Area, the mechanical calculation model of the pipe gallery foundation pit backfilling process was simulated by ABAQUS, and the pavement settlement and the change of the pipe gallery model under different construction conditions were simulated and verified. The results show that many external environmental factors have an impact on pavement settlement, and methods such as increasing the compaction degree of backfill soil and the slope of the foundation pit, reducing the width of the pit floor, and controlling the vehicle load after work can avoid the pavement damage caused by uneven settlement.