Urban Underground Space Use Research Articles

Estimation of the ecological carbon sink potential of using urban underground Space: A case study in Chengdu City, China

Urban carbon sinks from plant photosynthesis in urban blue-green spaces (BGSs) effectively sequester CO2 and achieve carbon neutrality. Building urban facilities underground saves land for the development of urban BGSs. Development and utilization of urban underground space (UUS) is increasing rapidly in most advanced cities globally, many of which are located in China. This study combined the planting design strategy of urban BGS and the vegetation carbon sequestration efficiency estimation method to quantitatively assess the ecological carbon sink potential of the use of UUS. Three types of BGSs: partly open green space (GPO), closed green space (GC), and partly open blue space (BPO), were first constructed based on their practicability in the city, and a planting strategy was designed for urban BGSs accordingly. Secondly, a model for the conversion of UUS development intensity into surface space to achieve ecological carbon sinks under three scenarios of UUS development intensity (low, medium, and high intensity) was constructed. Thirdly, methods for the calculation of carbon sequestration by GPO, GC, and BPO, were established based on the land-use carbon emission model. The developed method was finally validated through a case study in the Tianfu New District Directly Administered Area of Chengdu in Sichuan Province, China. The results of the study in Chengdu show that the higher the intensity of the use of UUS, the greater the proportion of carbon sink contribution to the CO2 emissions of the building industry for the planned population, and a maximum of 7% of carbon emissions absorbed from the building industry for the planned population was achieved. These findings serve as a reference for assessing the use of UUS to achieve urban carbon neutrality in other cities.

Thematic evaluation and optimisation countermeasures of urban underground public space based on IPA analysis method

A great deal of research has been carried out on the sustainable use of urban underground space, among which the importance of urban underground public space to urban development has been well proven. However, at present, most of the urban underground public spaces are constructed with the goal of supplementing the surface business, which leads to a large number of unused underground public spaces and low utilisation rate. Spaces rich in thematicity tend to have a higher attraction to the public, but many studies at this stage focus on the improvement of the physical environment of underground spaces, and there are few assessments of the thematic shaping of underground public spaces. Therefore, this study adopts the importance-satisfaction (IPA) model and takes the underground shopping mall of Zilinan-Fountain in Guiyang's old town as the research object to examine the relative relationship between the importance level of each evaluation element and the satisfaction of the crowd, and then to derive the factors that need to be focused on improvement. The analysis shows that the restoration and construction of special thematic scenes, the types of thematic businesses, the regular organisation of thematic activities or curatorial exhibitions, the number of resting seats, the clarity of the main axis of the space, the monitoring of the regional traffic flow, and the size of the area of the shared gathering space are the objects that need to be highly paid attention to, and can be improved to perfect the thematic creation of the underground public space.

Design recommendations for sustainable urban underground spaces

Considerable research has been devoted to sustainable urban underground space use, with the importance of urban underground spaces (UUS) for urban sustainability having been well documented. However, the focus of most research stems from an engineering or urban planning point of view, overlooking ways in which urban design can contribute to sustainable UUS. This paper aims to synthesize and illustrate urban design recommendations for sustainable UUS in an integrative and holistic manner, taking elements identified by other disciplines into account and reinterpreting them from an urban design point of view. The findings allow us to suggest recommendations on livability, connectivity, temporality and interdependency. By renewing the focus on urban design and making the recommendations explicit, the complexity of the subsurface is acknowledged. This means designers will become better able to master this complexity and thus design more examples of good practice and further enhance the added value of the subsurface for sustainable cities.

Planning an adaptive reuse development of underutilized urban underground infrastructures: A case study of Qingdao, China

Urban underground infrastructures (UUIs) are a vital component of built capital for urban sustainability. However, many cities are now home to a multitude of disused or underutilized UUIs, not least aged purpose-built underground facilities, causing a waste of valuable underground space resource assets. In the process of urban renewal, adaptive reuse can be an attractive solution to breathe new life into underutilized UUIs, while addressing some of the modern problems of the built environment by an economically feasible means. Nevertheless, there is a prevalent absence in the current literature of the overarching planning and decision-making approaches for an adaptive reuse development of underutilized UUIs. With the intention of addressing this shortfall, this paper first lays out development strategies, then sets the generic patterns for adaptive reuse of disused or underutilized UUIs. Taking the city of Qingdao, China as a case study, detailed planning and decision-making approaches with the aid of multi-source data and spatial analysis tools are presented. It is anticipated that the findings of this research will assist the adaptive reuse development of UUIs in providing theoretical guidance and empirical evidence, thereby enhancing the role of urban underground space use in contributing to urban revitalization and urban sustainability.

Forecasting Short-Term Passenger Flow of Subway Stations Based on the Temporal Pattern Attention Mechanism and the Long Short-Term Memory Network

Rational use of urban underground space (UUS) and public transportation transfer underground can solve urban traffic problems. Accurate short-term prediction of passenger flow can ensure the efficient, safe, and comfortable operation of subway stations. However, complex and nonlinear interdependencies between time steps and time series complicate such predictions. This study considered temporal patterns across multiple time steps and selected relevant information on short-term passenger flow for prediction. A hybrid model based on the temporal pattern attention (TPA) mechanism and the long short-term memory (LSTM) network was developed (i.e., TPA-LSTM) for predicting the future number of passengers in subway stations. The TPA mechanism focuses on the hidden layer output values of different time steps in history and of the current time as well as correlates these output values to improve the accuracy of the model. The card swiping data from the Hangzhou Metro automatic fare collection system in China were used for verification and analysis. This model was compared with a convolutional neural network (CNN), LSTM, and CNN-LSTM. The results showed that the TPA-LSTM outperformed the other models with good applicability and accuracy. This study provides a theoretical basis for the pre-allocation of subway resources to avoid subway station crowding and stampede accidents.

Geosystem services in urban planning

The paper considers the emerging concept of geosystem services (GS), highlights its importance for sustainable urbanization, and the use of urban underground space specifically. A theoretical framework to enable the incorporation of GS into urban planning has been suggested. GS complement ecosystem services (ES) by focusing on abiotic components and services of the environment. Clearly, sustainable urban development is one of the major challenges facing humanity today. In this study we explore how the concept of GS can help address the challenge of a sustainable urbanization via planning instruments. The paper reviews classifications of GS, planning approaches towards urban underground space, and experiences in inclusion of GS and ES in urban planning. Next, the paper elaborates a theoretical framework for the incorporation of GS in urban planning. The framework integrates knowledge on GS, man-made subsurface infrastructure, cultural assets, and traditional planning issues like land use, social and economic considerations. The paper further discusses various particularities, which urban planners may come across considering GS: (1) planning scales, (2) planning time frame, (3) GS inventory, (4) supply and demand for GS, (5) risks, vulnerabilities and disservices, (6) interplay between geosystem and infrastructure services, (7) planning documentation, (8) visualization and planning tools. Our research shows that the concept of GS has not yet been fully integrated into planning processes, despite the increasing need for its inclusion under the emerging development agenda of geothermal energy, hydrological and hydrogeological cycles management, and the rational use of urban underground space. The inclusion of GS into urban planning would constitute an important step forward to sustainable urbanization.

The spatial vitality and spatial environments of urban underground space (UUS) in metro area based on the spatiotemporal analysis

The expansion of China’s metro transportation systems has been accompanied by rapid growth in the urban underground space (UUS) that surrounds them. However, the vitality of these spaces varies considerably due to inefficiencies in the ways they are utilized. To investigate this issue, the present study analyzed the environmental factors involved in the spatial vitality of three UUSs in the Shanghai Metro area. The relevant spatial environments and population density of each UUS were measured using space syntax, field observation, and cross-sectional pedestrian count. Correlations between the variables of the spatial environment and spatiotemporal vitality were calculated for seven periods of the working day at the levels of the overall UUS, the underground public space (UPS), and the underground space of shopping malls (USSM). The results show that, the spatial vitality was found to correlate with environmental variables such as accessibility, visibility, spatial scale, business distribution, and the physiological and traffic environments. The impact of these variables changed according to the research scope of UUSs (the overall UUS, UPS, or USSM) and the time of day. The study demonstrates how the complex spatial environment impacted residents’ daily use of UUSs around the Shanghai metro area and will inform efforts to plan, design, and improve similar UUSs in the future.

Visualization and spatial analysis of socio-environmental externalities of urban underground space use: Part 1 positive externalities

Socio-environmental externality is one of the distinctive identities of urban underground space (UUS) use and a decisive factor in the decision-making process of UUS planning projects. A growing number of attempts have been made to address the quantification challenge in monetary terms, but failed to articulate the spatial impacts of UUS uses, i.e., the distributional and quantitative extent to which UUS use will facilitate urban sustainability of a specific location, thus incapable of adequately promoting and legitimating UUS planning agendas. The gap can be filled by the geographically referenced visualization and spatial analysis, which require different datasets and approaches for positive and negative externalities of UUS uses. Accordingly, this study will be presented in two parts: Part 1 focuses on how UUS use benefits urban development; Part 2 pays particular attention to the potential threats posed by UUS use to urban sustainability. This part 1 paper builds on the service replacement cost method (SRCM) framework, under which the visualization process of positive socio-environmental externalities requires multi-sourced spatial data such as land use data, UUS planning data, population data, comprehensive transportation data and socio-economic data. Valuation results of the case study showed that the aggregated value of the socio-environmental benefits amounted to approximately 3.7% of the local GDP in 2018, with the most prominent contributions sourced from underground rail transit infrastructures and followed by the UUS uses beneath alienated land parcels. The spatial analysis rationalized the UUS planning of the case study area by demonstrating that the distribution of positive socio-environmental externalities derived from UUS uses was consistent with the planning visions of boosting and revitalizing local development, while most planned UUS projects yielded much greater external benefits than estimated construction costs.

Visualization and spatial analysis of socio-environmental externalities of urban underground space use: Part 2 negative externalities

This paper presents the second part of the two-piece work for the visualization and spatial analysis of socio-environmental externalities of UUS uses. Since the positive socio-environmental externalities of urban underground space (UUS) use have been articulated in Part 1, this Part 2 paper will be devoted to evaluate the negative aspects of UUS development, i.e., the potential threats posed by UUS use to urban sustainability, which requires methodologically distinctive datasets and analyzing approaches compared with Part 1. Findings from this paper will enable a thorough picture of UUS’s role in urban development, both quantitatively and geographically. Consistent with Part 1, Part 2 presented in this paper also builds on the service replacement cost method (SRCM) framework, under which the compromised services of underground assets, namely geothermal energy, groundwater, geomaterials, historical heritage, space continuum and underground organisms, are identified as the monetarized negative externalities derived from UUS uses. The visualization process requires multi-sourced spatial data such as UUS planning data, construction approach data and geological data. Valuation results of the case study showed that the annual average of the aggregated socio-environmental costs of planned UUS uses amounted to approximately 3.2% of the external benefits. Among the calculated items, geothermal energy losses were proved to be the major source of negative socio-environmental externalities in terms of both quantity and spatial distribution. This study facilitates a holistic cost benefit analysis that incorporates socio-environmental benefits, socio-environmental costs and construction costs. Results of the case study proved that most of the planned UUS uses could yield positive net benefits, hence contributing to urban sustainability.

Underground space utilisation and new town development: Experiences, lessons and implications

In the urbanisation process of the past few decades, the use of urban underground space (UUS) has contributed to new town developments in many cities in the world. This offers an opportunity to map out and systematically describe the potential contributions of UUS for transport, land use, economic, environmental and social development in new towns for planners, designers and policy-makers to consider. This review synthesises key papers on UUS utilisation and new town development. It indicates that the requirements of intensive use of land resources, accessibility reasons, avoidance of urban problems experienced in old cities, cultural and modernity considerations, and the goal of building smart, low-carbon and sustainable cities drive UUS utilisation in new developments. Underground spaces have been developed in new towns in various forms, with subway, underground parking facilities and underground utility infrastructure being the more prevalent forms of UUS utilisation, and UUS utilisation in new towns varying in scale. UUS utilisation for new developments may confront many challenges related to various issues: relationships between new towns and old city centres; compact and high-density urban forms; transit accessibility; awareness of the significance of UUS; balance between market forces and government intervention; coordination of development; full utilisation of UUS resources; and decision-making support. Existing practices used in UUS development provide lessons from which to learn.

Planning and application of underground logistics systems in new cities and districts in China

Underground logistics systems (ULSs) has been an important topic and research hotspot for urban underground space use in China, especially for implementation in new cities and districts, as it is a necessary element to be considered for city underground space planning. Since these newly planned areas will face many challenges, including increasing logistics volume, spatial constraints etc. if we use the existing freight transport modes similar to old cities. Furthermore, the rapid developments of Chinese new cities provides an opportunity to implement innovative ULS freight transport systems and technology that are efficient and sustainable. Recently, ULS has been included officially in the planning and study for Beijing’s Sub-Center, the Yangtze River Demonstration District and other new cities and districts. However, the real value of ULS will not materialize unless it is successfully implemented. This paper presents the exploration, observations and findings of a few proposed ULS planning and research works in the new districts mentioned. The suitability of goods and freight types in ULS, logistic flow demand forecasting and ULS network systems integrated with underground metro or infrastructure are discussed. Both dedicated and integrated ULS network systems are also compared and analyzed. Despite the many advantages, many challenges and difficulties remain in the planning integration, technology adaptation and implementation of ULSs in new districts and cities, thus, interdisciplinary collaborations is one of the key success factors to ensure ULS can be brought to fruition.

The onset of underground urban planning in Flanders

Urban underground space (UUS) can be an effective means to meet the needs of the cities and simultaneously deal with societal and urban challenges. However, in Flanders the use of UUS remains to be one of the most forgotten urban assets and is characterised by a haphazard, uncoordinated ‘last resort’ practice detrimental to sustainable development. In a search for new possibilities for qualitative densification the Flemish Government instigated a policy exploration to investigate if efficient use of the UUS could be a possible solution for lowering the daily land take. This paper describes the process and content of the policy exploration and sets out policy recommendations. The paper concludes that although the merits of UUS have been thoroughly recognized and the significance of the subsurface in urban renewal is clear, the efficient use of UUS in Flanders and the fulfilment of Flemish policy objectives cannot be guaranteed without the development of UUS policy and the integration of UUS policy in the overall Flemish urban planning system. The research finds that a clear definition of planning factors for the use of UUS is necessary to support the transition from using the UUS to integration of the UUS into wider urban planning processes. It puts forward the need for a comprehensive list of planning factors, gathered in a holistic, integrated manner, necessary to transition from UUS projects to UUS planning.

Study on the Design of the Upper Space Parking Lot of Urban Multi-layer Tunnels

In recent years, with the continuous acceleration of the urbanization process, underground parking lots have developed rapidly, and they are continuously moving towards intelligence. Based on the multi-layer tunnel section of the Xiamen Haicang Subsea Tunnel, this paper conducts theoretical research on the liquid analysis of the surrounding area of the tunnel area, the graphic design of the parking lot, the architectural design, the function, and the fire prevention design. The research results are of great significance to the rational use of urban underground space, increase the utilization rate of underground parking lots and ease parking difficulties.

Low carbon effects of urban underground space

Urbanization is progressing rapidly, while problems raised by climate change are occurring across the globe. Cities are at the center of both of the two tendencies therefore, low carbon or zero carbon cities are being promoted. Urban underground space (UUS) is a key component in the process of urbanization and plays a significant role in creating low carbon cities, as highlighted in this paper. Meanwhile, UUS also involves unavoidable drawbacks regarding energy consumption in terms of lighting, ventilation and dehumidification. In this paper, the advantages of UUS in creating low carbon cities are analyzed, and a framework for calculating the positive low carbon effects derived from UUS use is established. Additionally, some alleviating measures in response to the potential low carbon disadvantages of UUS are proposed. Based on the analysis, some planning and design implications for the development of urban underground space in order to fulfill its role as a contributor to urban sustainability are discussed.

Going underground: An exploration of the interfaces between underground urban transport infrastructure and its environment

With the continued urbanization and densification of cities worldwide the planning, and use of urban underground space (UUS) is of clear interest to urban and transport planners; and asset owners/managers. Effective strategies for the management of UUS and its environment once built are required and critical insight of how current use of these spaces affect and are affected by each other, enables effective planning and asset management strategies to be developed now and for the future.This paper argues that the management of existing and development of new urban infrastructure and its interfaces with UUS requires consideration of what is/will be there; who does/will own it; and how it must/will be protected. However, there appears to be a gap in the literature relating to how and why these interfaces occur and how they could and should be managed effectively.Taking the case of existing urban underground metro infrastructure, this paper demonstrates how understanding the presence, property, and protection interfaces of urban underground infrastructure and its environment at different levels of consideration is essential to urban and transport planning and management.The paper concludes with a challenge to current strategies and proposals for the development and management of UUS and its environment, questioning whether they are fit for current and future demands and changes.

Determining the Optimal Use of Urban Underground Space (Selected Streets of Isfahan City)

Determining the Optimal Use of Urban Underground Space (Selected Streets of Isfahan City)

Scientific Principles for Shaping Underground Infrastructure of Megacities

The basic notion underlying urban underground development is that underground space is a non-renewable resource, therefore planning its use must be done in a sustainable, environmentally-responsible manner with due account taken of economic, functional, social, and legal aspects. This paper addresses issues related to the planning, siting, design, construction, operation and maintenance of underground structures in the city of Moscow. The mechanism of the interaction between an underground structure and the surrounding rock masses is described. It is shown that underground engineering can be significantly enhanced through the use of expert systems. The paper also discusses the need for changes to the legal framework for the use of urban underground space.

Study on the demand and driving factors of urban underground space use

For sustainable development of Urban Underground Space (UUS1UUS means Urban Underground Space.1), determination of the desirable volume and function share of UUS is of vital importance. However, prediction of demand for UUS remains a rather challenging task. Very little quantifiable information, which is a basis for comparative study and improvement of prediction methods, is currently available pertaining to UUS. Xinjiekou, the center of Nanjing city, is called the first commercial center of China. Employing precision mapping on site and inquiring with a variety of organizations concerned, all the developed UUS in the area of Xinjiekou has been investigated in detail. On the basis of the quantitative investigation, the development modes and functional ratios are compared with other Chinese and foreign cases. By quantitative and comparative studies, the demand and driving factors of UUS have been identified. It is also found that the study area has the potential to be further developed and improved. It is hoped that this paper will enhance knowledge about the quantitative characteristics of UUS use, and be helpful for the demand prediction and planning of UUS development.

Predetermined? – Systems Thinking for the Urban Subsurface

In recent years the topic of urban underground projects and infrastructure networks as well as their contribution to sustainability and resilience of cities has been widely addressed. Major projects deal with questions of interdependencies, mapping and untangling of the existing underground infrastructure web, which constitutes not only a service but also a major constraint for future projects and planning in the underground space. In addition, the use of urban underground space is more and more extended from purely ‘technical’ functions like infrastructure and storage to developing the space itself into, for example, shopping malls, extensions of museums or parking facilities, recreational spaces, archives, or computer centres. To capture and plan for these manifold interests in the long-term, a holistic approach to analyse the urban subsurface is needed which goes beyond the analysis of singular projects or networks. Masterplans which integrate the subsurface seem to be feasible but ultimately can only be successful if the underlying system properties are sufficiently understood. This paper reviews the development of system thinking as well as its applicability for analysis of the urban subsurface as multifunctional, holistic entity. Prospects and outstanding issues when adopting a systems perspective to a spatial entity are discussed in order to interpret what they might mean for the urban subsurface. In this context, the influence of system boundaries on system properties like flexibility, adaptability and resilience is highlighted, challenging the notion that the potential for further exploitation of the subsurface is predetermined by the local geology, the legacy of human impact and the advancement of technologies.

Lessons learnt from Urban Underground Space use in Shanghai—From Lujiazui Business District to Hongqiao Central Business District

This paper presents a case study on Urban Underground Space (UUS) use in Shanghai, China. Shanghai is at the forefront of China’s modernization construction, and also sets an example for other cities in China in the field of UUS use. Surging from 2million m2 in the early 1990s to over 68million m2 in recent years, the amount of UUS in Shanghai has reached a scale previously unimaginable. From the process of Shanghai UUS development, we can learn either valuable experiences from cases like Hongqiao Central Business District (CBD) or, inevitably, profound lessons from Lujiazui Business District. Reviewing and comparing such cases will demonstrate the importance of planning and legal procedures to the development and utilization of UUS and can facilitate the further promotion of UUS use in Shanghai.