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Technical Visits

Technical Visits

WTC2023 Technical Visits

WTC2023 would like to invite you to take part in the technical visits on Thursday 18th of May and enjoy the experience of touring the most exciting tunneling and underground excavations projects that are currently taking place in Attica.

To proceed with your technical visit booking please visit the WTC2023 Online Services Booking Form.

For additional information, please contact the Professional Congress Organizer at:


2023 World Tunnel Congress Booking Form

For Terms & Conditions, please click here

Technical Visits

on Thursday 18th of May

Historical Underground Visits

1. Athens Metro Line 4

The first phase of Line 4 (from Alsos Veikou to Goudi areas) is being constructed fully underground by the joint venture “AVAX AE – GHELLA SpA – ALSTOM TRANSPORT SA” following a tender award on 2021 from the Project Owner ATTIKO METRO S.A.

Main features of the Project

  • 8km line: double track TBM tunnel
  • 15 underground stations with platform screen doors
  • 9 intermediate or terminal shafts
  • 2km underground forestations, underground trumpet structures and connecting tunnels
  • A new Operation Control Center
  • A new repair workshop in the existing Depot area
  • Underground Train stabling and maintenance yards at both ends of the Line
  • Transfer connections at two existing Stations (Line 2 & Line 3)
  • 20 new 4-car automated driverless trains.

The Project’s estimated cost is 1,510,000,000.00 € and the estimated delivery time is 96 months.

Among the technical challenges of this Project is TBM tunneling under existing Metro tunnels and excavation of new stations close to operating Metro stations whose safety and activities should remain unaffected. Furthermore, boring or digging under or next to high buildings, sometimes old or historical ones in the city center, has to be performed securing their structural and serviceability standards. The risk of coming across archaeological findings during excavation works is always high in the Athens area and the issue of how to protect them while not impeding the works is of great importance.

The tour will start with a presentation of the Project at a construction site office. Delegates will then visit a number of worksites to view tunnelling works and construction of stations, shafts etc.
It is expected that by the time the Technical Visits take place, TBM tunneling works will have started and construction of cut & cover structures (stations, vent. shafts) as well as conventional tunneling will be in progress.

Cost per person : 20.00 €
limited participation on a first come first served basis

Photo Gallery

2. Underground Construction of National Railway Line in Athens

The Greek Public Railway Construction Company (ERGOSE) assigned in 2018 the construction of a four-track rail corridor, 2.36 km long of which approx. 1.9 km is fully underground, starting from the Athens Central Railway Station and ending at Sepolia area, in Athens Municipality. There the line connects to the new four-track rail corridor which was recently completed and opened to traffic. The rail corridor mostly runs within the occupation zone of the existing open air train tracks. The east half of the four-track corridor will serve suburban trains, whereas the west half will be used mainly for intercity services.

The project schedule has to provide for a number of constrains such as maintaining the existing surface train operation, safe construction close to adjacent buildings, close overpassing a Metro running tunnel and a Water Authority (EYDAP) culvert. The integrity and serviceability of all those structures is to be secured during the works, therefore modern instrumented monitoring is implemented.

When finished, the surface area above the underground corridor will serve 9 vertical streets which are currently interrupted due to the on-ground corridor. Moreover, landscaping will provide citizens with recreation areas of green (trees, shrubs).

Works are in full progress by the Contractor “J/V  INTRAKAT SA – SIDIRODROMIKA ERGA ATE” and Phase A is to be completed by 2024, while the whole project will be delivered by the end of 2025.

Following a brief presentation of the Project, we will visit a worksite to see construction work of the underground part of the Line. It will be a half-day visit.

Cost per person : 20.00 €
limited participation on a first come first served basis

Photo Gallery

3. The Hellinikon Project – Underground Coastal Road

The revitalization of the former Hellinikon Airport area is the biggest project of its kind in Europe and the most ambitious development project ever undertaken in Greece that will positively impact the local and national economy. It combines urban development, recreation facilities, a huge metropolitan park and seafront full accessible to the public. Access through metro and tram lines will be assured while the existing road along the shoreline will be reconstructed to become fully underground.

The Project of the Underground Coastal Road was assigned by the Owner LAMDA DEVELOPMENT to the Contractor AVAX SA and excavation works have already started. The underground road will begin at the area of Alimos and rise to surface at Ag. Kosmas marina. The purpose of this Project is to allow connection of the seashore front to the rest of the Hellinikon area.

The tour includes presentation of the Hellinikon Project at the Company’s office and then walk the delegates around the various worksites in the area especially in the underground coastal road.

Cost per person : 20.00 €
limited participation on a first come first served basis

Photo Gallery

4. DionyssoMarble – Underground exploitation of Pentelikon Marble

The famous marble that was used for the construction of the Parthenon in the 5th century BC is a deposit in the Mt. Pentelikon in Attica, about 20 km from Athens. In the ancient times, the huge pieces of stone had to be hauled to the building site by oxcart. The roadway used was a continual downhill, and followed the natural inclination of the land.

Pentelikon marble is currently exploited by Dionyssomarble who holds a leading position in the production, processing and trade of marble and other ornamental stone, marble dust and calcium carbonate filler. The increased demand for dimension stone in combination to quarrying in an environmentally sensitive area, has led the company to exploit part of its deposit using underground methods to minimize their environmental footprint.

To achieve this goal, the company participated in a three-year research program of the European Union, in the period 1999 – 2001. In cooperation with academic institutions and mining industries from EU countries, an integrated methodology of planning and programming for underground marble mining was developed.

The exploitation method is room and pillar with openings up to 15 meters wide, while the maximum height of the excavations is 30 meters. Following studies and simulations in collaboration with the School of Mining Engineering of the NTUA, preventive support measures (anchors) are implemented.

During the visit at Dionyssomarble, there will be an initial briefing by the company on site, its history and achievements and description of both the surface and underground mining methods. A visit to the quarry with emphasis on the underground excavations area will follow. A visit of the processing plant and the exhibition will conclude the excursion.

Cost per person : 20.00 €
*limited participation on a first come first served basis

Photo Gallery

5. Athens Metro Lines 2 & 3: Operations Control Centre

The Operations Control Centre (OCC) for Metro Lines 2 & 3 is located at the Syntagma Station, in the heart of Athens. It is the complex centre of train controls, communication, information & reports collection by the staff.  It is the point where instructions are passed on to staff on site and where the overall co-ordination for a safe and effective operation on a 24/7/365 basis is performed. 

Access to the visit location will be by actually riding Metro Lines 2 or 3 depending where the attendee is – from the Congress venue, go to the nearby Megaro Moussikis Station and take trains going toward Dimotiko Theatro Station, then get off at Syntagma Station and ascent to Concourse Level.

During the visit, the tasks of the OCC will be analyzed and the visitors will have an exclusive view of systems such as supervision and control of the signalling system, train movements, power and environmental system. An authority official of the Athens Metro will provide in-depth details of communication and co-ordination of all local staff as well as emergency services in case of an incident and restoration of traffic after the incident is over. Delegates will have the opportunity to ask questions about the various topics of operation and controlling of the Metro Lines. At the end of the visit, coffee and refreshments will be offered.

Estimated visit time at the OCC room:  1 – 1:30 hours (excluding delegate travel time)

Cost per person : 20.00 €
limited participation on a first come first served basis, maximum number of attendees: 50 (2 groups of 25)

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

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

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.

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.