Bibliometric analysis of research challenges and trends in urban underground space

The utilization and development of urban underground space play a crucial role in optimizing the layout of civic architecture and enhancing the urban ecological environment,which contributes toward increasing the overall carrying capacity and promoting sustainable development in megacities.To delve into the research progress of urban underground space,knowledge maps were created using the information visualization software VOSviewer.The literature was systematically extracted from three prominent databases,namely,Web of Science,Scopus,and China National Knowledge Infrastructure.According to the bibliometric analysis of the co-citation and core words co-occurrence,the trends and challenges of research on urban underground space were identified.As highlighted by the results obtained,it still remains highly challenging to achieve interdisciplinary collaboration in urban underground space research;the research trends of urban underground space consist of collaborative planning and whole life cycle sustainable development,multisource geological data informatization and resource evaluation,infrastructure design optimization,and intelligent construction.The knowledge map,drawn using bibliometric methods,offers a quantitative analysis of literature retrieval across various levels.It is recognized as an essential tool for exploring and identifying challenges and trends in urban underground space.

Development of urban underground space in coastal cities in China:A review

The development of urban underground space is a critical way to alleviate the lack of urban resources,and improve environmental conditions as well as residents'quality of life,which has important practical significance.As the most densely populated and economically developed areas,coastal cities face many challenges in underground space development owing to their unique environmental geological conditions.This study examined the current situation of underground space development,academic research,technology application,evaluation methods,planning,and legislation in coastal cities in China.On this basis,it analyzed the future development trends,and presented reasonable suggestions for the critical scientific and technical problems faced by the development of underground space in coastal cities.The key suggestions are as follows:it is necessary to define and clarify the critical geological issues,distributions,and hazards that affect underground space development and major engineering construction in coastal cities;the land-sea integrated detection technology for sea crossing bridges and submarine tunnels needs to be studied;in evaluating the suitability of underground space in coastal cities,the land and sea area evaluation factors should be integrated;and the evaluation system of landsea integration needs to be established.

Construction of Ecological Network for Urban Green Space System from the Perspective of Landscape Ecology:A Case Study of Wanzhou District, Chongqing Municipality

Green spaces in Wanzhou District, Chongqing Municipality were not closely linked and failed to form an integrated ecological network, this paper analyzed and assessed current situation of green spaces in the local area from the perspective of landscape ecology, and then established the landscape ecology-oriented ecological network construction, restructured green paces in Wanzhou District using the landscape composition of "patch–corridor–matrix", and connected the scattered green patches using green corridors, so as to form a reasonable ecological network of green spaces.

Analysis of the Response and Driving Forces of Urban Landscape Pattern during Urbanization of Zhangjiagang City in China

By taking Zhangjiagang City as the research object, with the guidance of 3S (GIS, GPS and RS) and the theory of landscape ecology, based on the remote sensing images from 1991 to 2006, land use maps and social-economic statistical data, by combining with gradient analytical method, eight landscape pattern metrics had been selected to analyze the urbanization of Zhangjiagang City and urban landscape pattern change characteristics at different stages of urbanization. The results showed that the urbanization of Zhangjiagang City could be divided into two stages which were the urbanization of Zhangjiagang City from 1991 to 2001 and the suburbanization of Zhangjiagang City from 2001 to 2006 based on landscape metrics' change characteristics. During urbanization, the response was obvious in the urban center of Zhangjiagang City, and urban landscape pattern changed greatly. During suburbanization, the response was obvious in the rural area of Zhangjiagang City and rural landscape pattern changed greatly. The urbanization of Zhangjiagang City conformed to the urbanization mode based on population theory and extension theory. Urbanization firstly affected the urban center, and then extended to its surrounding areas, and further influenced widespread rural areas. During suburbanization, agricultural land had decreased and been seriously destroyed; thus, it should strengthen the protection of agricultural land.

Urban and Rural Landscape Ecological Problem Produced by Urbanization

By using landscape ecology theory and measure,structure,layout,function and resources utilization of urban and rural landscape during urbanization process had been studied;urban and rural landscape problems brought by urbanization and reasons causing them had been analyzed.In terms of rural landscape ecological problems,degeneration of natural and semi-natural landscape caused ecological unbalance,disorder of landscape pattern caused decrease of ecological environmental quality,disharmony between new and old landscape caused loss of native characteristic,contradiction between land and population became acute,land waste and pollution were serious and ecological environment had been damaged.In terms of urban landscape ecological problem,damage of regional ecological environment gave rise to decrease of ecological function,natural and cultural landscapes with significant value had been destroyed,urban green space constantly decreased and landscape fragmentation degree increased,urban layout lacked of planning which led to spatial development problem.On this basis,corresponding countermeasures had been proposed.It pointed out that,as for rural landscape ecological problems,it should pay attention to landscape ecological planning and adjustment of layout,coordinate regional comprehensive development by completeness principle,effectively coordinate all kinds of contradictions,intensify the effort for rural land arrangement,and develop construction of ecological network;as for urban landscape ecological problems,it should lay stress on reasonable planning of landscape structural proportion,establishing reasonable landscape pattern,effectively constructing urban green land and regulating ecological environment.

Evolution of Waterfront Landscape Pattern Under Rapid Urbanization: A Case Study of Xuhui Riverside Zone in Shanghai

The urban waterfront area is in a special land-water communication zone and is an ecologically sensitive zone. It combines the characteristics of natural landscape and human landscape intertwined. The urbanization process continues to affect the natural and cultural environment of the waterfront, and environmental issues have become increasingly prominent. Taking Xuhui Riverside Zone as an example, this paper analyses the dynamic evolution process of the landscape, aiming at revealing the impact of the evolution of landscape pattern on urban ecological environment during the process of urbanization in China, so as to provide useful references for the planning and design of the waterfront space landscape of domestic and foreign cities.

Analysis of Geotechnical Engineering Safety Technology in Urban Underground Space Construction

With the accelerating pace of urbanization,the development and application of urban underground space has attracted much attention.In the construction of urban underground space,geotechnical engineering safety is the key point for construction.Based on this,this paper analyzes the application of geotechnical engineering safety technology in urban underground space construction,in hope that this analysis can provide a scientific reference for the rational application of geotechnical engineering safety technology as well as the construction and development of urban underground space.

Evaluation of urban underground space resources using a negative list method: Taking Xi'an City as an example in China

Utilization of urban underground space has become a vital approach to alleviate the strain on urban land resources,and to optimize the structure and pattem of the city.It is also very important to improve the city environment,build livable city and increase the capacity of the city.Based on the analysis of existing evaluation methods and their problems,a method for evaluating underground space resources based on a negative list of adverse factors affecting underground space development is proposed,to be primarily used in urban planning stages.A list of the adverse factors is established,including limiting factors,constraining factors and influencing factors.Taking Xi'an as an example,using a geographical information system platform,a negative list of adverse factors for the underground space resources in Xi'an City are evaluated,and preventive measures are proposed.Natural resources,exploitable resources,and the potential growth of exploitable underground space resources are evaluated.Underground space assessment in the different development stages of the city,collaborative utilization and safety evaluation for multiple subsurface resources,environmental impact and assessment,as well as evaluation methods based on big data and intelligent optimization algorithms are all discussed with the aim of serving city planning and construction.

Digital Ecological Design of River Landscapes in Urbanization

By comparing landscape patterns of suburban and urban rivers in the same flow path, and analyzing patch indexes of urban river landscapes, corresponding sustainable eco-design strategies were proposed, ecodesign theory system and eco-restoration design techniques were coupled, so as to explore new digital eco-design means of urban river landscapes by targeting at regional ecological consistency.

Construction Technology and Strategy of Natural Light Environment in Urban Underground Space

In underground space,daylighting plays an important role in increasing the spacious sense,improving the ventilation effect,and more importantly,reducing the negative visual and psychological effects brought by the underground space,such as enclosed monotony,unknown direction and isolation.In this paper,the technical means of utilizing natural light in underground space were elaborated from the two aspects of passive daylighting method and active daylighting method,aiming to bring natural light into the underground as much as possible so as to fully satisfy people's longing for nature for those who work and live in the underground space.

3D suitability evaluation of urban underground space using a variable weight method and considering ground restrictions

The evaluation of urban underground space(UUS)suitability involves multiple indicators.Assigning weight to these indicators is crucial for accurate assessment.This paper presents a method for spatially variable weight assignment of indicators using the order relation analysis method(G1-method),the entropy weight method,an improved grey relational analysis(GRA)and a set of spatial weight adjustment coefficients.First,the subjective and objective weights of indicators for engineering geological and hydrogeological conditions were determined by the G1-method and entropy weight method,respectively,and their combined weights were then obtained using the principle of minimum discriminatory information.This study highlighted the impact of surface restrictions,such as buildings,on UUS,and the degree of the influence of these buildings gradually decreased with the increase in depth of the rock and soil mass in UUS,which resulted in changes in weights of indicators with depth.To address this issue,a coefficient was defined as the standardized value of the ratio of additional stress applied by restrictions to the self-weight stress of soil at the same depth to modify the combined weights so that all weights of indicators could vary in space.Finally,an improved GRA was used to determine the suitability level of each evaluation cell using the maximum correlation criterion.This method was applied to the 3D suitability evaluation of UUS in Sanlong Bay,Foshan City,Guangdong Province,China,including 16 evaluation indexes.This study comprehensively considered the influence of multiple factors,thereby providing reference for evaluating the suitability of UUS in big cities.

Principles of Landscape Ecology in the Construction of Hydro-ecological Civilized City

Against the backdrop of global urbanization,ecological civilization problems have become increasingly prominent,among which water ecological civilization has been a focus of researches for being closely tied with urban life.Under the context of constructing water ecological civilization,this paper from the perspective of landscape ecological planning analyzed the connection of river and lake water systems,construction of fl ood and water diversion project,water pollution control,water ecological conservation and ecological river construction,based on different water ecological construction objectives;explored how to support landscape planning by fully using landscape ecological principles and landscape indexes;fi nally proposed to design more delicate objective-based landscape indexes and the overall landscape index model for water ecological construction.

Review of constraints and critical success factors of developing urban underground space

The development of urban underground space(UUS)is of great significance for sustainable urban development because it has potential to solve many urban problems.However,the development of UUS is limited because there are still a lot of constraints and challenges.To better understand the constraining factors of developing UUS and improve the development and utilization of UUS,this study conducts a comprehensive survey of existing literature retrieved from the Web of Science Core Collection database.Five main constraining factors,including the limited geological conditions,high cost,lack of natural light and ventilation,high incidence,and difficulty in collecting data and information on UUS,have been discussed to better understand how they affect the development of UUS.Based on the survey,the critical success factors of developing UUS,such as the effective governance structure,planning system for integrating UUS into urban development,coordination of the design of ground and underground,delineation of land property rights of UUS,and application of information techniques in the use of UUS,have been identified and discussed.In addition,knowledge gaps in the studies on development of UUS have been identified.Finally,the research trends and future directions have been proposed for better understanding and practice of UUS development.

Ecological Remediation Technology of Urban Landscape Water Body

Urban landscape water body is not only an important part of urban landscape construction,but also an important way to maintain landscape diversity and biodiversity,carrying the beautiful yearning of urban residents for natural life.A good state of urban landscape water body is crucial to the ecological environment of the city.However,due to the poor kinetic energy of urban landscape water body and the influence of various human factors,the quality of urban landscape water body often declines,and urban population is threatened by water security problems.Through the study of several water body ecological remediation technologies,relevant suggestions are put forward,in order to provide a reference for water pollution restoration and treatment in urban human settlement environment.

An experimental study on fire characteristics of urban complex underground space based on BIM

Compared with the space on the ground,if there is a fire in the urban complex underground space,the loss will be greatly harmful.In addition,the complex underground space is usually connected with other large space areas and densely populated.Once a fire occurs in the complex underground space,it will cause huge property losses and casualties.In order to reduce the risk of fire,it is necessary to deeply understand the development rules and characteristics of fire in the complex underground space of the city.This article has mainly carried on the following work:(I)A particularly complex model of the multi‐storey subway station was built.On this basis,three groups of comparative experiments were conducted to study the effects of fire power,fire location and smoke control system on fire development,and the conclusion that fire location is the most important factor for fire development was obtained;(II)In order to explore the entire space fire and the local space fire,CFD(Computational Fluid Dynamics)is used to build a large‐size fire model and a small‐size fire model respectively;(III)Multiple detector data as temperature slices were built,and it is expected to make full use of the simulation data to deduce the important index of fire location in the early stage of fire.All of the works in this paper will provide reference experimental data for the prevention and firefighting of a sudden fire in the complex underground space.

A collaborative approach for urban underground space development toward sustainable development goals:Critical dimensions and future directions

The utilization of urban underground space(UUS)offers an effective solution to urban problems but may also negatively affect urban development.Therefore,UUS development needs better concerted guidelines to coordinate various urban systems and the multiple components of the underground world.Sustainable Development Goals(SDGs),which should be viewed as important yardsticks for UUS development,do not explicitly mention urban underground space,although many of them are affected by both the positive and negative consequences of its development.To fill this gap,this review lays the foundations of relevant UUS concepts and uses exemplary cases to reveal that 11 out of 17 SDGs can be linked with UUS uses.These linkages also manifest that land administration,integrated planning,architectural design,and construction technology are critical dimensions for increasing the contributions of UUS to the realization of SDGs.To achieve multi-disciplinary synergies among these four critical dimensions,a collaborative approach framework based on spatial data infrastructure is required.Thus,this work provides academics and practitioners with a holistic view of sustainable UUS development.

Analysis on Landscape Pattern of Urban Green Space in Tianjin City

Based on IKONOS satellite image in August of 2008,and by using GIS technique and spatial pattern analysis software FRAGSTATS,the paper analyzed landscape pattern of urban green space in Tianjin City from the aspects of patch composition and level of category and landscape.The result showed that there were manymin-sized patches in Tianjin City while large patches occupied a large proportion of the total area of green space.Green spaces were unbalanced in distribution and unreasonable in structure.It suggested adjusting the structure of urban green space,reducing the degree of landscape fragmentation,strengthening the construction of large and mid-sized green patches,so as to improve ecological function of green space.

Evaluation of urban underground space resources using digitalization technologies

Exploitation and utilization of urban underground space resources is gaining increasing attention in cities’sustainable development.Due to the attributes of fragility and irreversibility,urban underground space resources can be extremely vulnerable to damage and it is often difficult in restoring their original state once damaged.Therefore,scientific and reasonable evaluation of urban underground space resources is of vital importance in urban planning and development.This paper first describes the content and methods for the evaluation of urban underground space resources,and introduces the digitalization technologies to handle the problems of strong subjectivity,low efficiency and rough precision encountered when using traditional evaluation tools.Then,the related concepts and main technologies for digitalization were demonstrated and an intelligent GIS-based engineering geology system was built.Based on the drilling information in Changzhou City,stratum standardization and 3D modeling of strata,underground structures and pipelines were conducted in the built intelligent system.Finally,with the help of spatial overlay analysis in the GIS-based platform and a combination of other digitalization technologies,the urban underground space resources of Changzhou City were evaluated.Maps of geological suitability were produced,which provide scientific guidance and reference for the exploitation and planning of urban underground space resources in Changzhou City.In addition,site selection for key projects was conducted based on the evaluation results using this platform.

Systems approaches to urban underground space planning and management-A review

The necessity to recognize the subsurface or underground and all its current and potential uses as part of our urban environment,to integrate this into urban planning and governance,and to foster conscious allocation of subsurface space has been increasingly recognized over the last century.At the same time,systems thinking as a‘buzz-word’has gained relevance for approaching complex problem areas in all kinds of disciplines including those preoccupied with the subsurface.This paper reviews the literature about urban underground planning through a systems-lens.To set this in context,it is outlined how organizational principles for the urban subsurface have evolved,and the main aspects of systems thinking are introduced followed by a discussion of how this thinking could be applied to the urban underground.Strategies and tools presented in the recent literature in the field are then reviewed based on this perspective,asking how systemic the proposed strategies and tools are when the local geology,as well as legal and institutional settings are accepted as a baseline for analysis or intervention.Systemic approaches built on this premise have the potential to capture existing and evolving complexities,foster a better understanding of the value of subsurface space for a city and ultimately enable an efficient and fair allocation of underground space.However,propositions for holistic solutions remain dispersed,interventions often remain based in an engineering mindset,and a shift in mind-set remains a challenge.More research in collaboration with local and regional administrations or authorities based on systems thinking frameworks could help to facilitate this shift.

The Planning of Urban Green Space System Based on the Concept of Conservation-oriented Landscape

Through analyzing problems in the planning of green space system in cities of China,strategies for constructing urban green space system are put forward based on the requirements of conservation-oriented landscape.