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“The underground space is often undervalued as an asset” | A conversation between Arnold Dix and Nikolaos Roussos

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“The underground space is often undervalued as an asset” | A conversation between Arnold Dix and Nikolaos Roussos

World Tunnel Congress 2023: “The underground space is often undervalued as an asset

A conversation between Arnold Dix, President of ITA

and Nikolaos Roussos, President of GTS

As the new edition of the WTC in Athens from 12 to 18 May approaches, Arnold Dix, President of the International Tunnelling and Underground Space Association and Nikolaos Roussos, President of the Greek Tunnelling Society, discuss several topics around tunnelling, its multiple challenges and the congress.

With the WTC approaching in May, what is the state of the tunnelling sector globally and particularly in Greece?

AD: Globally this sector has never been busier with major infrastructure being delivered as part of economic stimulus packages in many countries. Also the role of underground infrastructure in adaptive and resilient responses for the challenges posed by the changing climate has seen a boom in flood diversion, hydro power, sewerage and mountain transportation projects.

NR: We see this trend here in Greece and in Athens. Its underground network has expanded considerably in recent years and this development is now accelerating significantly. The Metro Line 3 Extension Project to Piraeus was successfully finished in October 2022, with the public opening of the final three new stations, Maniatika, Piraeus, and Dimotiko Theatro. The project, which included a 7.6 km long twin-track running tunnel, six new modern stations, and seven ventilation shafts, is one of the most significant expansions for the greater area of Athens and Piraeus region in decades.

Let’s stay on the tunnelling activity in Greece and especially in Attica region. A major plan for the extension of the metro network in Athens is under discussion.  Why are these projects essential?

NR: At this time, in Athens, a Metro network with over 110 stations is proposed, with 35 new stations in 9 extensions. After a decade of focusing Metro projects on the extension of Line 3 in Piraeus and the effort to begin the implementation of Line 4, new goals appear to be established for the coming years. The goal is to connect with other means, expand the network, and create new growth poles in the city, making Athens a friendlier city to its citizens and visitors.

Major plans for the extension of metro networks in big cities are essential for improving transportation, reducing congestion, promoting economic development, and enhancing urban mobility. These projects can have a significant positive impact on the lives of people in the city, making them a crucial investment for the future.

Sustainability in tunnelling and resilience against climate change. What’s your view? Does the scarcity of urban space resources make the underground space planning de facto more sustainable?

AD: The threats posed to urban environments like climate change, tend to relate to less reliable surface assets like roads, railways, power distribution, and surface drainage, because more frequent, higher intensity storm events and more severe weather (such as heat or cold), tend to damage and render existing surface infrastructure compromised. 

This then raises the prospect of more adaptive infrastructure of which the underground delivers many unique opportunities.  The sustainability of such options depends partly upon the consequences of building and operating them on the climate emergency itself.  Enormous improvements have been made to the environmental implications of building such infrastructure including low carbon materials and techniques. 

NR: Moreover, tunnels can provide additional space for sustainable infrastructure such as underground water storage and renewable energy production.

Regarding the scarcity of urban space resources, yes, planning for the use of underground space can be considered more sustainable due to the limited availability of above-ground space in urban areas. By utilizing the underground space for transportation, utility corridors, and other infrastructure needs, it can help reduce the demand for above-ground space, which can help preserve green space and improve the overall liveability of urban areas.

Precisely, the WTC 2023 will be under the sign of “Expanding Underground”. Is the underground space undervalued as an asset?

NR: There is a significant amount that can be done below the surface of our cities, and the underground space is often undervalued as an asset. There are several reasons to explain that. Firstly, there is a lack of awareness and understanding of the potential uses and benefits of underground space. Many people may not realize that the underground space can be used for more than just transportation tunnels and utility tunnels.

Secondly, there are technical and logistical challenges associated with developing underground space. Excavating and constructing underground structures can be complex and costly, and requires specialized knowledge and equipment.

Thirdly, there may be regulatory and legal barriers to developing underground space. For example, there may be restrictions on the use of underground space in certain areas or limitations on the height or depth of structures that can be built.

Arnold Dix

AD: The area under cities is a spatial resource that is dimensionally limited but usually underutilised and undervalued. 

There are enormous opportunities under most cities to augment the surface for greater human enjoyment and to deliver efficient and effective transportation, water, sewerage, energy, dangerous or confidential endeavours, strategic activities, and other complex human endeavours underground.

Sustainability in tunnelling and resilience against climate change. What’s your view?

AD: The threats posed to urban environments like climate change, tend to relate to less reliable surface assets like roads, railways, power distribution, and surface drainage, because more frequent, higher intensity storm events and more severe weather (such as heat or cold), tend to damage and render existing surface infrastructure compromised.

Nikolaos Roussos

NR: Tunnelling can help reduce the environmental impact of transportation by providing underground mass transit systems, which can reduce the need for individual cars and improve air quality. Additionally, tunnels can be used to provide underground utility corridors, which can reduce the need for overhead transmission lines and help protect against extreme weather events.

Regarding the scarcity of urban space resources, yes, planning for the use of underground space can be considered more sustainable due to the limited availability of above-ground space in urban areas. By utilizing the underground space for transportation, utility corridors, and other infrastructure needs, it can help reduce the demand for above-ground space, which can help preserve green space and improve the overall liveability of urban areas.

In conclusion, tunnelling can play an important role in promoting sustainability and resilience in the built environment, and the scarcity of urban space resources makes underground space planning an attractive option for meeting infrastructure needs. However, it is important to balance the potential benefits of underground development with the need for responsible planning and management to ensure that it is sustainable and does not have negative impacts on the environment or surrounding communities.

An extended version of this conversation will be available in the press kit of the WTC 2023.

Please find more information on the website: https://wtc2023.gr/

About the International Tunnelling and Underground Space Association:

The International Tunnelling and Underground Space Association (ITA) is a non-profit and non-governmental international organization that aims to promote underground space’s use as a solution to sustainable development. Founded in 1974 and operating out of Geneva, Switzerland, ITA currently associates with 78 Member Nations, 300 affiliated members, 14 Prime Sponsors and 60 supporters.

About the Greek Tunnelling Society:

The Greek Tunnelling Society (GTS), founded in 1995, is the established and official representative of Greece in the International Tunnelling Association (ITA-AITES). GTS is a non-profit body and aims to promote the key advantages of tunnels and underground structures from technical, environmental, social and economic point of view. The steering board of the GTS consists of 7 members, while the body of the GTS has more than 200 members. For more information on GTS, visit the official website.

Press Contact
ITA Contacts
Amélie Jolivet / Maxime Forgues
a.jolivet@giesbert-mandin.fr / +33 7 85 53 50 05
m.forgues@giesbert-mandin.fr / + 33 6 66 65 04 91

Professional Congress Organiser Contact
Promotion Team
Harry Tzanavaris
promo@wtc2023.gr / +30 210 6833600  

Tarcisio Celestino

Tarcisio Celestino was previously ITA President (2016-19) and President of the Brazilian Tunnelling Committee. He was the Animateur of the ITA Working Group 12 on Sprayed Concrete Use (2005-10). He earned his doctorate degree in Civil Engineering (Rock Mechanics) from the University of California, Berkeley (1981).

He is currently Professor at the University of Sao Paulo and employed by Themag Engenharia Ltda., Sao Paulo (Brazil), where he leads the Geotechnical Engineering, Engineering Geology &Transportation Engineering Design Groups. He is also responsible for the geotechnical designs of several hydroelectric power plants, subways, highways etc., including major underground works (since 1990). He has also acted as consultant.

Professor Celestino continues to contribute his knowledge for the graduate courses & research areas on Rock Mechanics & Underground Works, at the São Carlos Engineering School, University of São Paulo and for the ITACET Foundation.

2. Excursion of history and adventure in Lavreotiki
Sunday 14 May, 2023

Our destination is the exploitation galleys of one of the largest underground mines of Attica. The chambers of metal extraction, rich in recognisable minerals, combine the mystery of ancient drifts with the beauty of caves. We will wander underground for up to 3 hours and explore the maize of drifts, the chambers supported by natural as well as carved-out pillars and the stalactites decoration reminiscent of natural caves. Each of the routes we follow hides surprises waiting to be discovered! 

After we will visit the great “Chaos” sinkhole, a heart-shaped sinkhole formation 150m in diameter and 55m deep. This chiasm may have been formed by the collapse of a cave roof as many of the area’s mining tunnels end there.

Scientific theme: Underground mining activity in Lavrio

Duration: 6 hours inclusive

Detailed program

9.30-10.30 Athens-Lavrio

10.30-13.30 Underground mines

14.00-14.30 Stop at dolin “Chaos” and return to Athens

14.30 – 15.30 Lavrio-Athens

Cost per person: 40,00 €

*limited participation on a first come first served basis. In case participants are less than 20, the respective event will be cancelled and a refund wil be given.

Photo Gallery

1. We go down Athens underground. (Athens centre, moving around on foot)
Saturday 13 May, 2023

How many surprises can the Athens underground have in store for its visitors? The stroll will start from underground shelters and detention areas of the German Kommandatur, remnants of the 2nd World War in Athens. Then, we will take the steps that start off under a timeworn trap door on the side of a road or hidden away in a sidewalk flower–bed, that will lead us in a different, forgotten underground area of the city! For hundreds of years, underground pathways have been used for various and mysterious purposes. Some say that all underground pathways are interconnected although there is no proof of this. Nevertheless, the allure of an unknown world is always there, beneath the ground we walk on. We lift up the antiquated hatch and descend the stone steps.  In the catacomb, we come across tunnels of ancient aqueducts, roman baths and byzantine crypts. The Athens river is also found hidden below the ground, running in old galleys under the most central streets of Athens – we can hear the cars passing over our heads! 

We invite you to discover together the hidden secrets of our city!

Scientific theme: underground constructions of the 19th and 20th century.

Duration: Maximum of 4 hours.

Detailed program:

11.00 Meeting outside Metro Station Panepistimio

11.30 Memorial Site (Korai Street). Two-level underground shelter below the Mansion of Ethniki Insurance Company.

13.00 Catacombs of the Russian Church (Filellinon Street). Inside the catacombs a tunnel and a shaft from ancient Peisistratus aqueduct, ruins from roman baths and crypts of the Byzantine order of Likodimos -11th century.

14.00 Ilissos River (area of Panathenaic Stadium). The buried riverbed of Athens river Ilissos.

Cost per person : 35,00 €

*limited participation on a first come first served basis. In case participants are less than 20, the respective event will be cancelled and a refund wil be given.

Photo Gallery

Professor Kyriazis Pitilakis

Professor Kyriazis Pitilakis has more than forty years of intensive academic, research and professional experience in civil, earthquake and geotechnical engineering. Vice-President of the European Association of Earthquake Engineering (EAEE), ex- Chairman of the Technical Committee “Geotechnical Earthquake Engineering andAssociated Problems” (TC203) of the International Society of Soil Mechanics and Geotechnical Engineering (ISSMGE), and past President of the Greek Society of Earthquake Engineering. He is presently Professor Emeritus in Aristotle University, Thessaloniki, Greece and since 2019 visiting Professor in Tongji University, International Laboratory of earthquake Engineering (ILEE), Shanghai, China.

Coordinator and scientific responsible of numerous European research projects, namely EUROSEISTEST and SYNER-G, he has a long experience in European research activities in earthquake engineering, geotechnical engineering, vulnerability and risk assessment of civil engineering structures, infrastructures and lifelines. According to the recent Stanford classification he is among the top 10 leading researchers in Civil Engineering in Greece, and among the top 10 leading international researchers in specific topics like Soil Dynamics, Engineering Seismology and Geotechnical Earthquake Engineering.

Chairman of several international conferences including the 16th European Conference of Earthquake Engineering, Thessaloniki 2018 and invited keynote lecturer in many International Conferences. Author of more than 650 scientific papers (h-factor 57) published in peer review scientific journals, and conference proceedings, author and co-author in several books, editor of four books published in Springer Editions, all in relevant subjects of earthquake engineering, seismic risk and geotechnical earthquake engineering. Professor Kyriazis Pitilakis is founder and coordinator of EUROSEISTEST, a large scale experimental facility in earthquake engineering, soil dynamics and engineering seismology that is unique in Europe and worldwide. He supervised more that 30 PhD thesis and numerous of his students hold academic positions in Greece and worldwide.

Professor Kyriazis Pitilakis is strongly involved in the ongoing revision of EC8 (Part 1-Seismic Actions and Part 5-Seismic design of foundations, retaining structures, soilstructure interaction, liquefaction, slope stability and underground structures), while he has been international expert for the revision of other seismic codes worldwide.

He is member of the editorial advisory board in Springer editions (Geotechnical, Geological and Earthquake Engineering), member of the editorial board and reviewer of numerous scientific journals and member of many international societies in earthquake and geotechnical engineering.

Honors: Chevalier dans l’Ordre des Palmes Academiques, French Republic.
Thessaloniki 06.06.2022

Professor Marc Panet

The 12th Muir Wood lecture will be delivered by Professor Marc Panet during the WTC2023 in Athens. His nomination being a Muir Wood lecturer was proposed by the French Tunnelling & Underground Space Association (AFTES) as per ITA’s Statues and By-laws.

Marc Panet graduated in Civil Engineering at the École des Mines de Paris and obtained a Master degree at the University of California at Berkeley. He started his career in 1965 at the Laboratoire Central des Ponts et Chaussées, in Paris, where he was a Research Engineer, Head of the Geotechnical Department and Technical Director. In 1982 he joined the SHP Group, in Paris, as Scientific Director. From 1984 to 1996 he was the President and CEO of SIMECSOL; and from 1996 to 2000 President and CEO of FC International SA. Since then he has been working as a consultant. He taught at the École Nationale des Ponts et Chaussées, at the École des Mines and at the École Centrale des Arts et Manufactures, in Paris.

Marc has been in charge of numerous studies in geotechnical engineering for underground works, highways, bridges, and natural hazards. Among the main projects are: the Mont Blanc Tunnel (11.6km), the Frejus Road Tunnel (12.9 km), the Large Electron–Positron Collider (CERN in Geneva), the Channel Tunnel (from 1967 to the end of the construction), the Millau Bridge, the Loetschberg Base Tunnel (43 km), subways in Paris, Rennes, Caracas, Athens and Algiers, the slides of the city of Constantine (Algeria), the project of the suspended bridge on the Straits of Messina (Italy) and the project of the cable-stayed bridge on the Golden Horn (Turkey). He is presently involved in a large number of geotechnical projects.

He is the author of a large number of publications in professional journals and international conferences and of the well-known book “Calculation of tunnels using the convergence-confinement method”.

Marc Panet is a Honorary Member of the French Academy of Technology, Knight of the National Order of Merit and Knight of the Order of Academic Palms.