- Email: [email protected]
The Underground Atlas Project
Tunnelling and Underground Space Technology xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
Tunnelling and Underground Space Technology journal homepage: www.elsevier.com/locate/tust
The Underground Atlas Project D. Kaliampakos, A. Benardos ⇑, A. Mavrikos, G. Panagiotopoulos School of Mining and Metallurgical Engineering, National Technical University of Athens, Greece
a r t i c l e
i n f o
Article history: Received 7 November 2014 Received in revised form 30 January 2015 Accepted 22 March 2015 Available online xxxx Keywords: Underground space development Classification of underground space Global database of underground space sites
a b s t r a c t The systematic recording of underground structures, their location, use as well as other characteristics is something that is still missing from the global engineering community. The paper presents the development of the Underground Atlas Project which aims at gathering and indexing the major underground sites worldwide, becoming the focal point of information regarding subsurface structures. The main features of the project are found in the development of the electronic database to store and depict the spatial information of the site, as well as in the crowdsourcing concept that was selected for the data and information submission. To foster the submission process, a new taxonomy and categorization of underground space uses has been proposed, while a respective web service and mobile app was developed by the design team. The users can either browse through the records stored or, more importantly, can submit new content either by using their browser or by taking advantage of the geolocation capabilities of their mobile device. Finally, the Atlas will provide the opportunity for the meta-analysis of the data by using and benefiting from the accumulated knowledge and collective experience of the engineering community. Ó 2015 Elsevier Ltd. All rights reserved.
1. Introduction During the last decades the world has experienced an unprecedented population growth, especially in the urban areas. Since 2007 more people lived in urban areas than anywhere else in the rest of the planet. In addition, between 2011 and 2050, the world population is expected to increase by 2.3 billion, passing from 7.0 billion to 9.3 billion and it is estimated that the urban areas of the world will absorb all the population growth over the next four decades (Vassigh and vom Hove, 2012). Most of the population growth expected in urban areas will be concentrated in the cities and towns of the less developed regions (UN Habitat, 2010). Megacities already account for 9% of the world’s urban population whereas urban growth is spread unequally around the world, and the same is true for large urban agglomerations. Most of the megacities in the developed world are growing slowly, if at all. Tokyo remains the largest with 35 million inhabitants, but the fastest growth will be in the developing world (particularly in Asia and Africa), placing huge pressure on infrastructure. Unfortunately, with regards to the urban areas, all these have come at a cost. It is widely accepted that the lack of free surface space, the sorely high land prices and the deterioration of the environmental conditions are just a few of the repercussions of
⇑ Corresponding author. Tel.: +30 210 7722182; fax: +30 210 7722156. E-mail address: [email protected] (A. Benardos).
urbanization (Kaliampakos and Mavrikos, 2004). In this context the idea of the systematic use of the underground space gained ground and is considered an efficient solution for the sustainability problems of modern urban areas. During the last decades the utilization of urban underground space has been pivotal in helping modern cities alleviate their environmental and social problems as well as achieve their sustainability goals (Edelenbos et al., 1998; Ronka et al., 1998; Bobylev, 2009). The exploitation of this resource for urban areas has led to a variety of land-uses being transferred to underground space and the construction of increasingly more complex underground structures. The expanding network of urban underground structures, the diversity of land-uses and the need to integrate underground development in urban planning have highlighted the need to map and classify urban underground space uses at a local or regional scale (Edelenbos et al., 1998; Ronka et al., 1998; Takasaki et al., 2000; Admiraal, 2006) or to develop a virtual encyclopedia for underground spaces (Lavagno and Schranz, 2002). Research has focused on 3D geotechnical maps and 3D mapping of the underground space (Vähäaho, 1998, 2014; Monnikhof et al., 1999; Parriaux et al., 2004) and in some cases GIS tools were employed to deal with a specific underground use such as utility service infrastructure (Metje et al., 2007). Beside the above research efforts, there is still the need to study the underground space uses at a ‘‘macro’’ scale, to monitor and analyze the continuously growing experience of urban underground development at a global level. The various types of underground structures and land-uses hosted at the subsurface
http://dx.doi.org/10.1016/j.tust.2015.03.009 0886-7798/Ó 2015 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Kaliampakos, D., et al. The Underground Atlas Project. Tunnel. Underg. Space Technol. (2015), http://dx.doi.org/10.1016/ j.tust.2015.03.009
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D. Kaliampakos et al. / Tunnelling and Underground Space Technology xxx (2015) xxx–xxx
environment are neither systematically recorded nor adequately studied. In the past, various attempts to classify underground space have been developed based on function, geometry, depth, project size, building type, origin, etc. (Carmody and Sterling, 1993). Underground development is a multi-disciplinary field involving engineers, researchers, geologists, urban planners, city authorities and various stakeholders. All these disciplines require, among other, supervisory information regarding underground structures as well as trends, statistical indicators, etc. The present paper presents an attempt to address this subject with the development of an on-line electronic database where the ‘‘thousand faces’’ of underground development are registered and are accessible through the internet or by using mobile devices such as smartphones and tablets. The Underground Atlas Project has been undertaken by the Lab. of Mining and Environmental Technology on behalf of the Associated research Centers for the Urban Underground Space (ACUUS) organization. This effort of course is not only based on the development team but rather the project relies on the joined forces of thousands of underground development enthusiasts around the world, so as to become the central point of information for underground structures. The paper describes the structure, the methodology and the assumptions made as well as its purpose as a research tool for the study of underground development trends, statistics, etc. 2. Crowdsourcing inputs One of the main issues regarding the development of the Underground Atlas database concerns the actual data. Underground spaces are located in almost all the corners of the world and the process of photographing, getting geographic coordinates and relevant information for the most of them requires substantial amounts of time and resources. Furthermore, there would be important limitations regarding the ability to register new underground structures or even apply updates in the already registered underground spaces in case of land-use changes or expansions, etc. Taking these factors into consideration, the project adopted a more collective approach, one that would ensure both the registration of the underground spaces currently available but also, one that has the potential to support future needs. Therefore, the Underground Atlas database relies on crowdsourcing and the widespread use of mobile devices. The idea is that academic scholars, researchers, engineers, students, etc. in the field of underground development or even underground enthusiasts around the world can use the available features in their smartphones, namely the camera, GPS module and internet connection in order to register an underground structure in the Underground Atlas database. The combined efforts of all those parties substitute for the, otherwise huge, demand for centralized resources and offer great power and versatility to the database. 3. Taxonomy of underground space structures Given the complexity of the structures and the variability of the end-uses hosted in underground man-made environments the first major issue is to provide a sound basis that would allow for a comprehensive registration of all types of underground structures. There are many attempts to categorize and classify underground structures either by simply using their general type and shape (e.g. tunnel, cavern, shaft) or by including their general use (e.g. transportation tunnel, food storage cavern, etc.). Carmody and Sterling (1993) used the classification groupings for underground space use that were intended to help identify reference projects for potential new applications. They chose the general categories of: function, geometry, origin, site features and project features.
Table 1 Major classification groupings of underground space use (after Carmody and Sterling, 1993). Major grouping
Major subcategories
Function Geometry
Residential, non-residential, infrastructure, military Type of space, fenestration, relationship to surface, depth, dimensions, scale of project Natural, mined, end use Geography, climate, land use, ground conditions, building relationships Rationale, design, construction, age
Origin Site features Project features
The subcategories of these groups can be further analyzed for the discrimination of underground space uses (Table 1). Carmody and Sterling (1993) in their work noted that there can be no acceptable purely hierarchical classification scheme to fit all the varied potential uses. However, it seems that the most wellstructured and comprehensive categorizations for underground space designs are the ones based on the end-use approach of the structures. The taxonomy there is made either in a simple manner by selecting the principal function of the structure or with respect to a characteristic value of the underground developed space. Furthermore, it is common to find a two-step categorization of the uses; first a cognate clustering is made, followed by all the uses that comprise that particular cluster. Ronka et al. (1998), proposed a categorization for the underground space according to their functions, namely, space intended for use by the general public, traffic space, technical maintenance facilities, industrial and production facilities, and special-use facilities. Moreover, they also proposed the feasible target depths for underground space development with respect to their functions. Thus, they provided an extra categorization with respect to their construction depth. Benardos (2002) provided a categorization of underground space structures by using their end-use and with respect to their general type (tunnel, cavern, shaft). Edelenbos et al. (1998) in the report for the strategic utilization of underground space in Netherlands used the two-step characterization, where they first discern the primary functions and in a second step the detailed function types of the underground space development. Takasaki et al. (2000), on behalf of the Japanese Tunnelling Association, used a very comprehensive similar approach by first identifying the purpose followed by the type of the underground structure, for the general planning of the underground space in Japan. Also, using this very principle, Bobylev (2009) proposed the characterization of underground space with respect to the services provided by the Urban Underground Space (UUS) to its potential users, identifying nine major sectors (transport, construction, water supply, utilities transport, waste management, energy storage, culture and amenity and, finally, buildings and structures). Bobylev (2010) has also made a comprehensive registration of all UUS in Alexanderplatz, Berlin, quantifying the use of urban underground space use by function, distribution of underground infrastructure by depth and volume of developed underground space per land area. 4. Proposed categorization of underground space structures In the case of the Underground Atlas Project, the criterion selected for the primary categorization for the underground sites is following the end-use approach. It can guide the users to a more correct demarcation of structures and can work more efficiently with new types of uses that can emerge in the future. Yet, it was decided to use the end-use type criterion even more directly, by bringing the potential underground space uses in the first categorization level. Thus, instead of focusing on the formation of
Please cite this article in press as: Kaliampakos, D., et al. The Underground Atlas Project. Tunnel. Underg. Space Technol. (2015), http://dx.doi.org/10.1016/ j.tust.2015.03.009
D. Kaliampakos et al. / Tunnelling and Underground Space Technology xxx (2015) xxx–xxx
clusters of similar group types, the individual characteristic of the end-use is the dominant categorization element. In this manner, the main types and uses of underground structures are presented in a fairly straightforward and simple manner, allowing for the non-expert or the non-experienced user to understand the functions of the underground sites. As the project heavily relies on the ‘‘crowd-sourcing’’ concept, simplifying the data inputs and the description of the facility could result in a more active participation of the ‘‘underground space’’ enthusiasts. Furthermore, to minimize categorization problems, the decision to include unknown site types in the submission process was taken as an additional measure to allow for a more active public participation. Hence, the ‘‘I am not sure’’ option has been added so as that such difficult to define cases would be specially treated and fully identified and characterized at a later stage by the project’s administration team. The main aim of the Atlas is not to cause a chaotic illustration of the service functions of underground structures. To achieve this, the categorization should comply with certain principles in terms of uses, which on one hand can allow trends to emerge but at the same time keep a balance between depicted details and the inclusion of the whole diversity of underground space uses. The first step toward succeeding in the above pursuit was to include a general categorization stage, relating to the site’s present condition in terms of service availability. Thus, instead of introducing an age/time specific threshold (e.g. site commissioned after 1950/in service for more than 50 years) that could be thought as an arbitrary selected criterion, the underground sites are characterized by their functioning state, irrespective of age or condition. They are discerned as either being ‘‘Active’’ or ‘‘Historical’’. The first is easy to understand, while the latter is associated with any underground facility that was created in the past, but at present time, it is not used or utilized for its primary/initial function. Therefore, it rather serves as monument or place of historic importance. This approach seems well suited for the case of underground sites and can provide distinction even in extreme cases where newly built underground environments have now become obsolete, while, older structures still function under their original service concept. For example, many underground bunkers or military deployment sites with not more of 50 years of life are now out of service, while on the other hand, metro stations are still operating even after 100 more years since they were first commissioned. ‘‘Historical’’ sites are included in the Atlas as they are an integral part of the underground space evolution. However, the categories under this label are kept to a minimum and five major functions are discerned, as presented below: Underground cities (Historical): Underground habitats built for protection from weather conditions or other threats. Infrastructure (Historical): Water tunnels, sewage systems, etc. built by ancient civilizations. Military facilities (Historical): Underground structures built for military purposes. Religious monuments (Historical): Underground temples, catacombs, etc. Various (Historical): Any other historical underground structures that do not fall into one of the above-mentioned categories. For the case of the ‘‘Active’’ underground types, the categorization is more extended and namely 23 primary functions are proposed. These are briefly described below, while the complete proposed taxonomy used in the Atlas is given in Table 2. Athletic/sport centers: Underground space, hosting athletic/ sports activities.
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Table 2 Proposed categorization of underground structure types. Underground facility type
Main function
Historical
Underground cities (historical) Infrastructure (historical) Military facilities (historical) Religious monuments (historical) Various (historical)
Active
Athletic/sport centers Power plants Repositories Storage facilities Oil storage Gas storage Civil protection shelters Cultural/educational centers Underground cities Dwellings and geospaces Malls Notable parking stations Laboratories Vaults Megatunnels (>10 km) Underwater tunnels Utility tunnels Metro/rail systems Notable metro stations and intermodal facilities Sewage/water treatment plants Waste management systems Flood management systems Other
Power plants: Underground infrastructure developed for the production of energy. Repositories: Underground facilities developed to store hazardous or radioactive waste. Storage facilities: Underground warehousing, logistics and/or light manufacturing/industrial facilities. Oil storage: Caverns for storing crude oil or oil products and fuel. Gas storage: Caverns, salt domes, etc. (excluding depleted oil fields) for storing natural gas. Civil protection shelters: Underground structures for the protection of civilians in case of war or other threats. Cultural/educational facilities: Underground museums, libraries, university campuses, religious centers, etc. Underground cities: Extensive underground pedestrian networks, retail shops, cafes, restaurants, cinemas, etc. linked with metro stations and lobbies of buildings. Dwellings and geospaces: Underground houses/hotels/bars/ restaurants, etc. Malls: Underground complexes with retail shops, cinemas, cafes, restaurants, etc. Notable parking facilities: Underground car parks. Laboratories: Underground facilities for research and experiments. Vaults: Underground spaces built to protect and preserve various valuable items. Megatunnels (>10 km): Long underground road or railway tunnels. Underwater tunnels: Tunnels constructed underwater, including submerged floating tunnels, on/under the seafloor. Utility tunnels: Small cross-section tunnels containing water pipes, electricity and telecommunication lines, etc. Metro/rail systems: Underground railway networks. Notable metro stations and intermodal facilities: Underground stations and intermodal facilities. Sewage/water treatment plants: Underground facilities used for the treatment of sewage or water.
Please cite this article in press as: Kaliampakos, D., et al. The Underground Atlas Project. Tunnel. Underg. Space Technol. (2015), http://dx.doi.org/10.1016/ j.tust.2015.03.009
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Waste management systems: Underground municipal waste collection/transportation networks and automated vacuum collection systems (AVAC). Flood management systems: Tunnels, etc. to deal with water flooding. Other: Any other active underground structures that do not fall into one of the above-mentioned categories. In proposing the above mentioned classification, the design team has made a number of assumptions. The uses selected cover the majority of the uses found in the underground structures, nevertheless specific categories were omitted or their importance was lowered on purpose. The omission has mainly to do with underground military installations. Although important and still widely used, it is a very sensitive function, thus, it was decided not to be included and depicted in the Atlas. Furthermore, with respect to the tunnels category, it was decided to focus on the most important ones (with length more than 10 km, underwater tunnels, etc.) and not try to include all the world tunnels in the Atlas. This is because tunneling is now becoming a contemporary construction practice and the population of the existing tunnels would overwhelm any other existing underground type. The same applies to the parking stations and the metro stations where the users are requested to submit cases of special design and/or technical interest. Finally, as already stated the ‘‘I’m not sure’’ category also exists for users that are unable to properly identify the correct underground use type. Such identification will be made by the members of the administrative team, with the help of local experts.
5. Implementation of the project 5.1. Technical details The Underground Atlas, both the content and the website shell, are hosted in a web server (http://u-atlas.metal.ntua.gr) and are accessible through any web browser. Furthermore, a free android mobile application has been developed and is available through
the Google Play Store (https://play.google.com/store/apps/details?id=com.ntua.metal.u_atlas) so as to assist the users in using the Atlas’ database on-the-go. The general architecture of the Underground Atlas and some of the components used for its development are given in Fig. 1. As it can be seen, the web and the mobile app provide an integrated platform for the submission and management of the underground sites and their related data and information. A number of open-source software packages were used for the development of the project. The Underground Atlas website is based on a CMS (content management system) software, and more particularly the Cartaro distribution (geOps, 2014) of the Drupal CMS. Drupal is an open source content management platform built, used and supported by an active and diverse community of people (Drupal, 2014). It is quite popular as a CMS with effective features, especially for community websites that deal with content uploaded by the end users, while, it also includes geospatial capabilities. The management of the spatial data of the underground sites is made possible using the Geofield and OpenLayers modules. The data input widget is an OpenLayers map, where the end user may identify the location of the underground site. To help users locate the position of the underground site, various base layers were added to the input map, like the Google Maps Satellite, Google Maps Normal, Google Maps Physical, OpenStreetMap and more. To develop The Underground Atlas Project Android app, DrupalGap was chosen. DrupalGap is an open source mobile application development kit for Drupal websites, which uses Drupal, PhoneGap, jQuery Mobile and jDrupal (DrupalGap, 2014). The fields for adding content (underground sites) are similar to those of the website. They vary in terms of the widgets by which end users input the various data, and specifically to that of the Geofield and the image. For the Geofield, the GPS of the mobile device provides the current location of the user in the form of latitude and longitude values, while the image field activates the on-board camera of the mobile device so that the user may capture a picture. Furthermore, the Geofield module’s code was modified and updated, under the open source concept, by the Underground Atlas development team in order to properly function and interact with the website. Finally, to present the content in a map, Leaflet
Fig. 1. Architecture of the Underground Atlas Project.
Please cite this article in press as: Kaliampakos, D., et al. The Underground Atlas Project. Tunnel. Underg. Space Technol. (2015), http://dx.doi.org/10.1016/ j.tust.2015.03.009
D. Kaliampakos et al. / Tunnelling and Underground Space Technology xxx (2015) xxx–xxx
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Fig. 2. General view of the Underground Atlas Project website.
Fig. 3. Screenshots from the Underground Atlas Project mobile app. The Leaflet map for browsing (a) and the ‘‘Add content’’ screen (b).
Please cite this article in press as: Kaliampakos, D., et al. The Underground Atlas Project. Tunnel. Underg. Space Technol. (2015), http://dx.doi.org/10.1016/ j.tust.2015.03.009
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(Agafonkin, 2014), an open source lightweight JavaScript library for mapping, has been implemented to the app. 5.2. Data management and user interface To present the data related to the various underground sites, the website provides a world map that projects the locations of the submitted underground sites, categorized as proposed in Table 2. The user can select a particular site by clicking on its icon to get more detailed information, as shown in Fig. 2. The same functions apply to the mobile app, slightly altered and simplified to better suit the small screen size, the native GPS, the onboard camera and the touchscreen mode (Fig. 3). Apart from the browsing feature of the Atlas, the users can submit their contribution by filling in the requested data fields through their web-browsers or mobile devices by either pinpointing the underground site’s location on the map provided or by
simply using the geolocation capabilities of their smartphones. The data management is done through Drupal CMS, where each content type (underground site) consists of several fields (input data). The information that the user may submit is the following: Title; the title of the underground site. Type; the use of the underground site. Location; the geographical position of the underground site. Description; a brief description of the underground site. Image; a representative image of the underground site. Structure type; the structure type of the underground site. Construction year; the construction year of the underground site. Dimensions; length, height, width or diameter of the underground structure as well as total floor area or volume. Author: The user who contributed the above information.
Fig. 4. The detailed webpage for each underground site contains all the submitted information.
Please cite this article in press as: Kaliampakos, D., et al. The Underground Atlas Project. Tunnel. Underg. Space Technol. (2015), http://dx.doi.org/10.1016/ j.tust.2015.03.009
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From the above inputs, only the title and location are required in order for a submission to be successful, however, the user is encouraged to provide as many information as possible. Some of the above details are selected from a list (e.g. use and structure type of the site), while there are also others where the user can directly register their values in the form of text or numbers. An example submission of an underground site is shown in Fig. 4. In this particular screen information relating to the location of the site is given in great detail, a brief description and a representative photo of the site, as well as the other already identified type of information. At this stage, the project is in its initial steps and the design team, with the help of the first members of the Atlas, has included some characteristic examples of underground sites (aprox. 35). They cover notable underground sites found internationally as well as a comprehensive listing of the underground sites located in Greece. Greece in particular is used as a case example of how to submit information regarding underground uses (UUs). We hope that the publication of the paper will be the onset for a more dynamic submission of information. The utilization of the users’ contribution will finally assist in gaining access to the collective experience of the community by gathering, classifying and analyzing the data inputs. The access and analysis of this accumulated experience can be most beneficial in identifying general trends in underground construction, in searching for patterns in construction types, in learning from successful cases and by being aware of possible problems. The aim is to provide the framework for the users to perform their own search and produce customized statistics on demand, allowing for a direct dissemination of the stored information.
6. Conclusions – discussion Urban underground space development is widely considered as an efficient way for contemporary urban areas to alleviate the negative effects of urbanization and to achieve their sustainability goals. Nowadays, underground space is being developed in every large metropolitan area of the world. Urban underground development has experienced a boom in both the number of projects developed and in the uses being transferred to the subsurface. However, this process, despite its importance, is still lacking a central point of reference, a monitoring and indexing service of the various important steps taken from the engineering community. The accumulated wealth of information, experience, technological applications and innovations, engineering solutions, etc. is continuously growing in size, nevertheless it is not adequately recorded nor is it quickly disseminated at an international level. City authorities, engineers and various stakeholders, especially in urban areas in a phase of transition to megacities, would be greatly benefited by having access to that data. The Underground Atlas Project aims at providing such a service, gathering the scattered pieces of information, organizing and redistributing them so that everyone involved in the underground space development can benefit from the accumulated experience. Of course, given the complexity of underground structures and the diversity of land-uses hosted in the underground space, certain decisions and assumptions are necessary in order to produce a sound result. To this end, the taxonomy of the Underground Atlas Project adopts a three-layer structure, where underground space use is classified firstly by defining whether it is still active or not, secondly by its main function (e.g. underground storage facility, underground sewage treatment plant, etc.) and thirdly by its construction method (cut-and-cover, room and pillar, cavern, etc.). The decision to keep the classification structure rather simple
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facilitates the active participation of volunteers not fully familiar with underground works. The project takes advantage of state-of-the-art technology such as GIS software and electronic databases as well as the, nowadays, widespread use of smartphones (with their ability to geolocate data and to transmit and receive information through broadband connections). Since the demand for centralized resources in order to complete such a project would be very high, an alternative approach was selected and the project relies on crowdsourcing. The collective approach through the crowdsourcing concept, which is used for the data inputs, can become the greatest advantage of the project. The database will be a powerful tool in the hands of researchers, academics and various stakeholders with an interest in underground space development as it can provide customized statistical analyses and regional surveys based on land-use, structure type, etc. Should the international underground development community embrace this effort and provide not only valuable data but also opinions and improvement proposals for the project then it is expected that soon the Underground Atlas Project will be able to provide a comprehensive picture of the underground space worldwide. References Admiraal, J.B.M., 2006. A bottom-up approach to the planning of underground space. Tunn. Undergr. Space Technol. 21 (3–4), 464–465. Agafonkin, V., 2014. An Open-Source JavaScript Library for Mobile-Friendly Interactive Maps (accessed 09.14). DrupalGap, 2014. The Open Source Mobile Application Development Kit for Drupal Websites . Vähäaho, I., 1998. From geotechnical maps to three-dimensional models. Tunn. Undergr. Space Technol. 13 (1), 51–56. Vähäaho, I., 2014. Underground space planning in Helsinki. J. Rock Mech. Geotech. Eng. 6 (5), 387–398. Vassigh, A., vom Hove, T., 2012. Urban Population Growth Between 1950 and 2030 (accessed 09.14).
Please cite this article in press as: Kaliampakos, D., et al. The Underground Atlas Project. Tunnel. Underg. Space Technol. (2015), http://dx.doi.org/10.1016/ j.tust.2015.03.009
Contents lists available at ScienceDirect
Tunnelling and Underground Space Technology journal homepage: www.elsevier.com/locate/tust
The Underground Atlas Project D. Kaliampakos, A. Benardos ⇑, A. Mavrikos, G. Panagiotopoulos School of Mining and Metallurgical Engineering, National Technical University of Athens, Greece
a r t i c l e
i n f o
Article history: Received 7 November 2014 Received in revised form 30 January 2015 Accepted 22 March 2015 Available online xxxx Keywords: Underground space development Classification of underground space Global database of underground space sites
a b s t r a c t The systematic recording of underground structures, their location, use as well as other characteristics is something that is still missing from the global engineering community. The paper presents the development of the Underground Atlas Project which aims at gathering and indexing the major underground sites worldwide, becoming the focal point of information regarding subsurface structures. The main features of the project are found in the development of the electronic database to store and depict the spatial information of the site, as well as in the crowdsourcing concept that was selected for the data and information submission. To foster the submission process, a new taxonomy and categorization of underground space uses has been proposed, while a respective web service and mobile app was developed by the design team. The users can either browse through the records stored or, more importantly, can submit new content either by using their browser or by taking advantage of the geolocation capabilities of their mobile device. Finally, the Atlas will provide the opportunity for the meta-analysis of the data by using and benefiting from the accumulated knowledge and collective experience of the engineering community. Ó 2015 Elsevier Ltd. All rights reserved.
1. Introduction During the last decades the world has experienced an unprecedented population growth, especially in the urban areas. Since 2007 more people lived in urban areas than anywhere else in the rest of the planet. In addition, between 2011 and 2050, the world population is expected to increase by 2.3 billion, passing from 7.0 billion to 9.3 billion and it is estimated that the urban areas of the world will absorb all the population growth over the next four decades (Vassigh and vom Hove, 2012). Most of the population growth expected in urban areas will be concentrated in the cities and towns of the less developed regions (UN Habitat, 2010). Megacities already account for 9% of the world’s urban population whereas urban growth is spread unequally around the world, and the same is true for large urban agglomerations. Most of the megacities in the developed world are growing slowly, if at all. Tokyo remains the largest with 35 million inhabitants, but the fastest growth will be in the developing world (particularly in Asia and Africa), placing huge pressure on infrastructure. Unfortunately, with regards to the urban areas, all these have come at a cost. It is widely accepted that the lack of free surface space, the sorely high land prices and the deterioration of the environmental conditions are just a few of the repercussions of
⇑ Corresponding author. Tel.: +30 210 7722182; fax: +30 210 7722156. E-mail address: [email protected] (A. Benardos).
urbanization (Kaliampakos and Mavrikos, 2004). In this context the idea of the systematic use of the underground space gained ground and is considered an efficient solution for the sustainability problems of modern urban areas. During the last decades the utilization of urban underground space has been pivotal in helping modern cities alleviate their environmental and social problems as well as achieve their sustainability goals (Edelenbos et al., 1998; Ronka et al., 1998; Bobylev, 2009). The exploitation of this resource for urban areas has led to a variety of land-uses being transferred to underground space and the construction of increasingly more complex underground structures. The expanding network of urban underground structures, the diversity of land-uses and the need to integrate underground development in urban planning have highlighted the need to map and classify urban underground space uses at a local or regional scale (Edelenbos et al., 1998; Ronka et al., 1998; Takasaki et al., 2000; Admiraal, 2006) or to develop a virtual encyclopedia for underground spaces (Lavagno and Schranz, 2002). Research has focused on 3D geotechnical maps and 3D mapping of the underground space (Vähäaho, 1998, 2014; Monnikhof et al., 1999; Parriaux et al., 2004) and in some cases GIS tools were employed to deal with a specific underground use such as utility service infrastructure (Metje et al., 2007). Beside the above research efforts, there is still the need to study the underground space uses at a ‘‘macro’’ scale, to monitor and analyze the continuously growing experience of urban underground development at a global level. The various types of underground structures and land-uses hosted at the subsurface
http://dx.doi.org/10.1016/j.tust.2015.03.009 0886-7798/Ó 2015 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Kaliampakos, D., et al. The Underground Atlas Project. Tunnel. Underg. Space Technol. (2015), http://dx.doi.org/10.1016/ j.tust.2015.03.009
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environment are neither systematically recorded nor adequately studied. In the past, various attempts to classify underground space have been developed based on function, geometry, depth, project size, building type, origin, etc. (Carmody and Sterling, 1993). Underground development is a multi-disciplinary field involving engineers, researchers, geologists, urban planners, city authorities and various stakeholders. All these disciplines require, among other, supervisory information regarding underground structures as well as trends, statistical indicators, etc. The present paper presents an attempt to address this subject with the development of an on-line electronic database where the ‘‘thousand faces’’ of underground development are registered and are accessible through the internet or by using mobile devices such as smartphones and tablets. The Underground Atlas Project has been undertaken by the Lab. of Mining and Environmental Technology on behalf of the Associated research Centers for the Urban Underground Space (ACUUS) organization. This effort of course is not only based on the development team but rather the project relies on the joined forces of thousands of underground development enthusiasts around the world, so as to become the central point of information for underground structures. The paper describes the structure, the methodology and the assumptions made as well as its purpose as a research tool for the study of underground development trends, statistics, etc. 2. Crowdsourcing inputs One of the main issues regarding the development of the Underground Atlas database concerns the actual data. Underground spaces are located in almost all the corners of the world and the process of photographing, getting geographic coordinates and relevant information for the most of them requires substantial amounts of time and resources. Furthermore, there would be important limitations regarding the ability to register new underground structures or even apply updates in the already registered underground spaces in case of land-use changes or expansions, etc. Taking these factors into consideration, the project adopted a more collective approach, one that would ensure both the registration of the underground spaces currently available but also, one that has the potential to support future needs. Therefore, the Underground Atlas database relies on crowdsourcing and the widespread use of mobile devices. The idea is that academic scholars, researchers, engineers, students, etc. in the field of underground development or even underground enthusiasts around the world can use the available features in their smartphones, namely the camera, GPS module and internet connection in order to register an underground structure in the Underground Atlas database. The combined efforts of all those parties substitute for the, otherwise huge, demand for centralized resources and offer great power and versatility to the database. 3. Taxonomy of underground space structures Given the complexity of the structures and the variability of the end-uses hosted in underground man-made environments the first major issue is to provide a sound basis that would allow for a comprehensive registration of all types of underground structures. There are many attempts to categorize and classify underground structures either by simply using their general type and shape (e.g. tunnel, cavern, shaft) or by including their general use (e.g. transportation tunnel, food storage cavern, etc.). Carmody and Sterling (1993) used the classification groupings for underground space use that were intended to help identify reference projects for potential new applications. They chose the general categories of: function, geometry, origin, site features and project features.
Table 1 Major classification groupings of underground space use (after Carmody and Sterling, 1993). Major grouping
Major subcategories
Function Geometry
Residential, non-residential, infrastructure, military Type of space, fenestration, relationship to surface, depth, dimensions, scale of project Natural, mined, end use Geography, climate, land use, ground conditions, building relationships Rationale, design, construction, age
Origin Site features Project features
The subcategories of these groups can be further analyzed for the discrimination of underground space uses (Table 1). Carmody and Sterling (1993) in their work noted that there can be no acceptable purely hierarchical classification scheme to fit all the varied potential uses. However, it seems that the most wellstructured and comprehensive categorizations for underground space designs are the ones based on the end-use approach of the structures. The taxonomy there is made either in a simple manner by selecting the principal function of the structure or with respect to a characteristic value of the underground developed space. Furthermore, it is common to find a two-step categorization of the uses; first a cognate clustering is made, followed by all the uses that comprise that particular cluster. Ronka et al. (1998), proposed a categorization for the underground space according to their functions, namely, space intended for use by the general public, traffic space, technical maintenance facilities, industrial and production facilities, and special-use facilities. Moreover, they also proposed the feasible target depths for underground space development with respect to their functions. Thus, they provided an extra categorization with respect to their construction depth. Benardos (2002) provided a categorization of underground space structures by using their end-use and with respect to their general type (tunnel, cavern, shaft). Edelenbos et al. (1998) in the report for the strategic utilization of underground space in Netherlands used the two-step characterization, where they first discern the primary functions and in a second step the detailed function types of the underground space development. Takasaki et al. (2000), on behalf of the Japanese Tunnelling Association, used a very comprehensive similar approach by first identifying the purpose followed by the type of the underground structure, for the general planning of the underground space in Japan. Also, using this very principle, Bobylev (2009) proposed the characterization of underground space with respect to the services provided by the Urban Underground Space (UUS) to its potential users, identifying nine major sectors (transport, construction, water supply, utilities transport, waste management, energy storage, culture and amenity and, finally, buildings and structures). Bobylev (2010) has also made a comprehensive registration of all UUS in Alexanderplatz, Berlin, quantifying the use of urban underground space use by function, distribution of underground infrastructure by depth and volume of developed underground space per land area. 4. Proposed categorization of underground space structures In the case of the Underground Atlas Project, the criterion selected for the primary categorization for the underground sites is following the end-use approach. It can guide the users to a more correct demarcation of structures and can work more efficiently with new types of uses that can emerge in the future. Yet, it was decided to use the end-use type criterion even more directly, by bringing the potential underground space uses in the first categorization level. Thus, instead of focusing on the formation of
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clusters of similar group types, the individual characteristic of the end-use is the dominant categorization element. In this manner, the main types and uses of underground structures are presented in a fairly straightforward and simple manner, allowing for the non-expert or the non-experienced user to understand the functions of the underground sites. As the project heavily relies on the ‘‘crowd-sourcing’’ concept, simplifying the data inputs and the description of the facility could result in a more active participation of the ‘‘underground space’’ enthusiasts. Furthermore, to minimize categorization problems, the decision to include unknown site types in the submission process was taken as an additional measure to allow for a more active public participation. Hence, the ‘‘I am not sure’’ option has been added so as that such difficult to define cases would be specially treated and fully identified and characterized at a later stage by the project’s administration team. The main aim of the Atlas is not to cause a chaotic illustration of the service functions of underground structures. To achieve this, the categorization should comply with certain principles in terms of uses, which on one hand can allow trends to emerge but at the same time keep a balance between depicted details and the inclusion of the whole diversity of underground space uses. The first step toward succeeding in the above pursuit was to include a general categorization stage, relating to the site’s present condition in terms of service availability. Thus, instead of introducing an age/time specific threshold (e.g. site commissioned after 1950/in service for more than 50 years) that could be thought as an arbitrary selected criterion, the underground sites are characterized by their functioning state, irrespective of age or condition. They are discerned as either being ‘‘Active’’ or ‘‘Historical’’. The first is easy to understand, while the latter is associated with any underground facility that was created in the past, but at present time, it is not used or utilized for its primary/initial function. Therefore, it rather serves as monument or place of historic importance. This approach seems well suited for the case of underground sites and can provide distinction even in extreme cases where newly built underground environments have now become obsolete, while, older structures still function under their original service concept. For example, many underground bunkers or military deployment sites with not more of 50 years of life are now out of service, while on the other hand, metro stations are still operating even after 100 more years since they were first commissioned. ‘‘Historical’’ sites are included in the Atlas as they are an integral part of the underground space evolution. However, the categories under this label are kept to a minimum and five major functions are discerned, as presented below: Underground cities (Historical): Underground habitats built for protection from weather conditions or other threats. Infrastructure (Historical): Water tunnels, sewage systems, etc. built by ancient civilizations. Military facilities (Historical): Underground structures built for military purposes. Religious monuments (Historical): Underground temples, catacombs, etc. Various (Historical): Any other historical underground structures that do not fall into one of the above-mentioned categories. For the case of the ‘‘Active’’ underground types, the categorization is more extended and namely 23 primary functions are proposed. These are briefly described below, while the complete proposed taxonomy used in the Atlas is given in Table 2. Athletic/sport centers: Underground space, hosting athletic/ sports activities.
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Table 2 Proposed categorization of underground structure types. Underground facility type
Main function
Historical
Underground cities (historical) Infrastructure (historical) Military facilities (historical) Religious monuments (historical) Various (historical)
Active
Athletic/sport centers Power plants Repositories Storage facilities Oil storage Gas storage Civil protection shelters Cultural/educational centers Underground cities Dwellings and geospaces Malls Notable parking stations Laboratories Vaults Megatunnels (>10 km) Underwater tunnels Utility tunnels Metro/rail systems Notable metro stations and intermodal facilities Sewage/water treatment plants Waste management systems Flood management systems Other
Power plants: Underground infrastructure developed for the production of energy. Repositories: Underground facilities developed to store hazardous or radioactive waste. Storage facilities: Underground warehousing, logistics and/or light manufacturing/industrial facilities. Oil storage: Caverns for storing crude oil or oil products and fuel. Gas storage: Caverns, salt domes, etc. (excluding depleted oil fields) for storing natural gas. Civil protection shelters: Underground structures for the protection of civilians in case of war or other threats. Cultural/educational facilities: Underground museums, libraries, university campuses, religious centers, etc. Underground cities: Extensive underground pedestrian networks, retail shops, cafes, restaurants, cinemas, etc. linked with metro stations and lobbies of buildings. Dwellings and geospaces: Underground houses/hotels/bars/ restaurants, etc. Malls: Underground complexes with retail shops, cinemas, cafes, restaurants, etc. Notable parking facilities: Underground car parks. Laboratories: Underground facilities for research and experiments. Vaults: Underground spaces built to protect and preserve various valuable items. Megatunnels (>10 km): Long underground road or railway tunnels. Underwater tunnels: Tunnels constructed underwater, including submerged floating tunnels, on/under the seafloor. Utility tunnels: Small cross-section tunnels containing water pipes, electricity and telecommunication lines, etc. Metro/rail systems: Underground railway networks. Notable metro stations and intermodal facilities: Underground stations and intermodal facilities. Sewage/water treatment plants: Underground facilities used for the treatment of sewage or water.
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Waste management systems: Underground municipal waste collection/transportation networks and automated vacuum collection systems (AVAC). Flood management systems: Tunnels, etc. to deal with water flooding. Other: Any other active underground structures that do not fall into one of the above-mentioned categories. In proposing the above mentioned classification, the design team has made a number of assumptions. The uses selected cover the majority of the uses found in the underground structures, nevertheless specific categories were omitted or their importance was lowered on purpose. The omission has mainly to do with underground military installations. Although important and still widely used, it is a very sensitive function, thus, it was decided not to be included and depicted in the Atlas. Furthermore, with respect to the tunnels category, it was decided to focus on the most important ones (with length more than 10 km, underwater tunnels, etc.) and not try to include all the world tunnels in the Atlas. This is because tunneling is now becoming a contemporary construction practice and the population of the existing tunnels would overwhelm any other existing underground type. The same applies to the parking stations and the metro stations where the users are requested to submit cases of special design and/or technical interest. Finally, as already stated the ‘‘I’m not sure’’ category also exists for users that are unable to properly identify the correct underground use type. Such identification will be made by the members of the administrative team, with the help of local experts.
5. Implementation of the project 5.1. Technical details The Underground Atlas, both the content and the website shell, are hosted in a web server (http://u-atlas.metal.ntua.gr) and are accessible through any web browser. Furthermore, a free android mobile application has been developed and is available through
the Google Play Store (https://play.google.com/store/apps/details?id=com.ntua.metal.u_atlas) so as to assist the users in using the Atlas’ database on-the-go. The general architecture of the Underground Atlas and some of the components used for its development are given in Fig. 1. As it can be seen, the web and the mobile app provide an integrated platform for the submission and management of the underground sites and their related data and information. A number of open-source software packages were used for the development of the project. The Underground Atlas website is based on a CMS (content management system) software, and more particularly the Cartaro distribution (geOps, 2014) of the Drupal CMS. Drupal is an open source content management platform built, used and supported by an active and diverse community of people (Drupal, 2014). It is quite popular as a CMS with effective features, especially for community websites that deal with content uploaded by the end users, while, it also includes geospatial capabilities. The management of the spatial data of the underground sites is made possible using the Geofield and OpenLayers modules. The data input widget is an OpenLayers map, where the end user may identify the location of the underground site. To help users locate the position of the underground site, various base layers were added to the input map, like the Google Maps Satellite, Google Maps Normal, Google Maps Physical, OpenStreetMap and more. To develop The Underground Atlas Project Android app, DrupalGap was chosen. DrupalGap is an open source mobile application development kit for Drupal websites, which uses Drupal, PhoneGap, jQuery Mobile and jDrupal (DrupalGap, 2014). The fields for adding content (underground sites) are similar to those of the website. They vary in terms of the widgets by which end users input the various data, and specifically to that of the Geofield and the image. For the Geofield, the GPS of the mobile device provides the current location of the user in the form of latitude and longitude values, while the image field activates the on-board camera of the mobile device so that the user may capture a picture. Furthermore, the Geofield module’s code was modified and updated, under the open source concept, by the Underground Atlas development team in order to properly function and interact with the website. Finally, to present the content in a map, Leaflet
Fig. 1. Architecture of the Underground Atlas Project.
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Fig. 2. General view of the Underground Atlas Project website.
Fig. 3. Screenshots from the Underground Atlas Project mobile app. The Leaflet map for browsing (a) and the ‘‘Add content’’ screen (b).
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(Agafonkin, 2014), an open source lightweight JavaScript library for mapping, has been implemented to the app. 5.2. Data management and user interface To present the data related to the various underground sites, the website provides a world map that projects the locations of the submitted underground sites, categorized as proposed in Table 2. The user can select a particular site by clicking on its icon to get more detailed information, as shown in Fig. 2. The same functions apply to the mobile app, slightly altered and simplified to better suit the small screen size, the native GPS, the onboard camera and the touchscreen mode (Fig. 3). Apart from the browsing feature of the Atlas, the users can submit their contribution by filling in the requested data fields through their web-browsers or mobile devices by either pinpointing the underground site’s location on the map provided or by
simply using the geolocation capabilities of their smartphones. The data management is done through Drupal CMS, where each content type (underground site) consists of several fields (input data). The information that the user may submit is the following: Title; the title of the underground site. Type; the use of the underground site. Location; the geographical position of the underground site. Description; a brief description of the underground site. Image; a representative image of the underground site. Structure type; the structure type of the underground site. Construction year; the construction year of the underground site. Dimensions; length, height, width or diameter of the underground structure as well as total floor area or volume. Author: The user who contributed the above information.
Fig. 4. The detailed webpage for each underground site contains all the submitted information.
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From the above inputs, only the title and location are required in order for a submission to be successful, however, the user is encouraged to provide as many information as possible. Some of the above details are selected from a list (e.g. use and structure type of the site), while there are also others where the user can directly register their values in the form of text or numbers. An example submission of an underground site is shown in Fig. 4. In this particular screen information relating to the location of the site is given in great detail, a brief description and a representative photo of the site, as well as the other already identified type of information. At this stage, the project is in its initial steps and the design team, with the help of the first members of the Atlas, has included some characteristic examples of underground sites (aprox. 35). They cover notable underground sites found internationally as well as a comprehensive listing of the underground sites located in Greece. Greece in particular is used as a case example of how to submit information regarding underground uses (UUs). We hope that the publication of the paper will be the onset for a more dynamic submission of information. The utilization of the users’ contribution will finally assist in gaining access to the collective experience of the community by gathering, classifying and analyzing the data inputs. The access and analysis of this accumulated experience can be most beneficial in identifying general trends in underground construction, in searching for patterns in construction types, in learning from successful cases and by being aware of possible problems. The aim is to provide the framework for the users to perform their own search and produce customized statistics on demand, allowing for a direct dissemination of the stored information.
6. Conclusions – discussion Urban underground space development is widely considered as an efficient way for contemporary urban areas to alleviate the negative effects of urbanization and to achieve their sustainability goals. Nowadays, underground space is being developed in every large metropolitan area of the world. Urban underground development has experienced a boom in both the number of projects developed and in the uses being transferred to the subsurface. However, this process, despite its importance, is still lacking a central point of reference, a monitoring and indexing service of the various important steps taken from the engineering community. The accumulated wealth of information, experience, technological applications and innovations, engineering solutions, etc. is continuously growing in size, nevertheless it is not adequately recorded nor is it quickly disseminated at an international level. City authorities, engineers and various stakeholders, especially in urban areas in a phase of transition to megacities, would be greatly benefited by having access to that data. The Underground Atlas Project aims at providing such a service, gathering the scattered pieces of information, organizing and redistributing them so that everyone involved in the underground space development can benefit from the accumulated experience. Of course, given the complexity of underground structures and the diversity of land-uses hosted in the underground space, certain decisions and assumptions are necessary in order to produce a sound result. To this end, the taxonomy of the Underground Atlas Project adopts a three-layer structure, where underground space use is classified firstly by defining whether it is still active or not, secondly by its main function (e.g. underground storage facility, underground sewage treatment plant, etc.) and thirdly by its construction method (cut-and-cover, room and pillar, cavern, etc.). The decision to keep the classification structure rather simple
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facilitates the active participation of volunteers not fully familiar with underground works. The project takes advantage of state-of-the-art technology such as GIS software and electronic databases as well as the, nowadays, widespread use of smartphones (with their ability to geolocate data and to transmit and receive information through broadband connections). Since the demand for centralized resources in order to complete such a project would be very high, an alternative approach was selected and the project relies on crowdsourcing. The collective approach through the crowdsourcing concept, which is used for the data inputs, can become the greatest advantage of the project. The database will be a powerful tool in the hands of researchers, academics and various stakeholders with an interest in underground space development as it can provide customized statistical analyses and regional surveys based on land-use, structure type, etc. Should the international underground development community embrace this effort and provide not only valuable data but also opinions and improvement proposals for the project then it is expected that soon the Underground Atlas Project will be able to provide a comprehensive picture of the underground space worldwide. References Admiraal, J.B.M., 2006. A bottom-up approach to the planning of underground space. Tunn. Undergr. Space Technol. 21 (3–4), 464–465. Agafonkin, V., 2014. An Open-Source JavaScript Library for Mobile-Friendly Interactive Maps
Please cite this article in press as: Kaliampakos, D., et al. The Underground Atlas Project. Tunnel. Underg. Space Technol. (2015), http://dx.doi.org/10.1016/ j.tust.2015.03.009