The queen’s university geomechanics group in Kingston, Ontario, has been involved in tunnelling-related research, development and graduate training since 2002. To celebrate their 15th anniversary and to continue a tradition of field-based training, the group embarked this summer on a 3,500km odyssey through Austria, Italy, Switzerland and Germany to gain first hand experience of operations at 12 active tunnel and cavern construction sites (including five TBM drives in progress, numerous active blasted or and mechanically excavated headings, and many more completed excavations) in addition to many other sites of geological engineering interest. Fourteen graduate students participated in the 16-day adventure led by Mark Diederichs with assistance by Jean Hutchinson, professors in the department of geological sciences and geological engineering at Queen’s. The students carried out research on all sites and projects along the way, producing professional and informative written material for the guidebook and providing highly-informative and focussed field presentations en route as part of their course deliverables.
In addition to tunnelling-related work, the Queen’s group also carries out R&D related to safe, long-term geological options for nuclear waste disposal, ground instability and geo-risk related to mining and infrastructure corridors, and engineering geophysics for geotechnical applications. The group currently includes 20 graduate students and research assistants and is directed by Diederichs with co-leadership by Hutchinson and Nicholas Vlachopoulos. Of the more than 60 graduates (Masters and PhD) since 2002, many of the students have been very active in the Tunnelling Association of Canada and most past graduates have gone on to successful careers in geotechnical consulting or construction related directly to tunnelling, in addition to mining and geo-hazard mitigation. A number have gone into academia and currently lead R&D groups with a significant emphasis on applied tunnelling research.
This latest overseas adventure follows on from a series of tunnel focussed field courses/tours mounted every three years starting in 2008 (with highlights including two construction faces of the Gotthard Tunnel as well as the Torino Metro), in 2011 (a trip that included the Sparvo TBM, the Ceneri Base Tunnel and TBM construction at the Nant de Drance hydro scheme) and in 2014 (this trip focussed on mining and engineering geology in Chile and Peru).
In the intervening years there have also been three trips to Greece, involving both Queen’s graduates, organised by Vlachopoulos with assistance from Diederichs. The Greek field course is a tour of most of the major active tunnel projects in Greece and has been run in conjunction with the graduate student program for tunnelling at the National Technical University of Athens (under Paul Marinos).
This latest expedition started (and ended) in Munich, Germany. After a feverish first day (Thursday, June 15) coordinating arrivals and logistics, the group had an early morning start to drive to the north end of the Brenner Base Tunnel (south of Innsbruck, Austria). With the organisational and expert assistance of Guido Venturini (of SWS), the group visited a main tube top heading under construction (NATM) as well as an exploratory/service tunnel heading being bored with a 7.9m open gripper TBM. After a scenic drive over the Brenner Pass, the team visited a TBM assembly cavern and numerous headings developed from the Mules Adit on the Italian side of the tunnel project.
After a glorious weekend visiting the famous Tres Cime in the Dolomite Mountains, investigating the site of the 1963 Vajont Dam and landslide disaster in Longarone, and surveying the geotechnical challenges of Venice, the team headed back up to Austria to visit the Granitztal and Koralm Base Tunnel (west and east drives). The next three days of tunnel project visits were enabled by the enthusiastic assistance of Giorgio Hoefer-Oellinger of Geoconsult. Descending the shaft near Wolfsberg, Austria, the group was able to experience the challenges in the western headings (KAT 3) associated with deforming ground in NATM headings and in a single shield TBM boring. This was followed by a glorious morning drive over the mountain range above the tunnel, ending at the eastern KAT2 workings and a visit to the head of a double-shield TBM drive (complete with numerous ground related challenges) and the main emergency transfer cavern and rescue tunnel under construction. This visit was followed by a unique opportunity to visit the main shaft and logistics cavern as well as four main headings of the Semmering Base Tunnel in eastern Austria.
After a lengthy traverse from eastern to western Austria, the team experienced a wide range of surface and construction challenges (intakes, tunnels, caverns, dams) associated with the hydro-electric generation projects at Gemeinschaftskraftwerk Inn (GKI) and Obervermuntwerk II (Vorarlberger Illwerke AG), both near Feldkirch, Austria. We must acknowledge the invaluable assistance of Helmut Wannenmacher for this phase of the trip.
From here we entered Switzerland. First stop was a full day tour of the Gonzen Iron Mine in Sargans, a complex network of tunnels, shafts and mine workings with active extraction dating from Roman times until the 1960s. This full-day tour took the group deep into the mountain to experience the legacy of mining over the centuries. A day of engineering geology (on foot, by car and by train) followed as the group investigated past landslide disasters, current slide and rockfall hazards and remediation works from Goldau to Goschenen. Along the way, the students explored the history and past challenges of tunnelling in Switzerland from the present (Gotthard Base Tunnel Portal at Erstfeld) to the recent past (Gotthard Road Tunnel) to the historic works of the Old Gotthard Rail Tunnel (opened 1882) from Goschenen to Airolo as well as the nearby Spiral Tunnels of Wassen. A number of previously top-secret military tunnels and caverns in the alps, only recently opened to the public, were thoroughly investigated, including the Sasso San Gottardo artillery base deep in the mountains above the Gotthard Pass. Passing through the Furka Base Tunnel (opened 1982) via a rail bound car ferry (with the car windows open of course) was a highlight, as were scenic side trips including a cable-car ride to an overview of the 26km-long Aletsch Glacier.
On days 13 and 14, the focus shifted to hydro-electric generation and nuclear waste repository engineering. Site visits included tours of numerous dams (inside and out) in the Grimsel area and one power house in operation. The Grimsel Test Site (established in 1984) is an underground research laboratory linked to the access tunnel for the KWO power plant north of Grimsel Pass. Here past and present excavations and underground experiments (geomechanics, hydromechanical, geochemical, etc.) in granitic rock of the Alps can be viewed and explored. To the north in the Jura Mountains the Mt. Terri Underground Laboratory provided a similar experience with a focus on repository construction and long-term safety in shale rock. Tim Vietor and Renate Spitznagel of NAGRA were instrumental in setting up this leg of the tour. The once-in-a-lifetime trip came to a climax with a two-day focus on German tunnelling and tunnel innovation. A comprehensive tour of the TBM factory in Schwanau hosted by Martin Herrenknecht and coordinated by Karin Baeppler was a tour highlight. The final day was a busy one, starting with a visit of the north TBM drives (11m diameter mixed shield), the surface logistics and a tour of tunnel ground freezing operations under an existing rail corridor in the south. This was coordinated by the project’s design manager, Marc Kemmler.
The afternoon and the final tunnel visit of the tour focussed on the Stuttgart 21 project. The tour kicked off in the impressive Fildertunnel construction yard in south Stuttgart. The visit included a trip to the working head of the 10.8m multi-mode shield machine as well as multiple headings driven conventionally, in challenging conditions including water sensitive anhydrite.
Matthias Tuertscher and Stefan Flachhuber organised the perfect tour and a perfect end to an incredible adventure. The students and professors of the Queen’s geomechanics group thank all of the many additional individuals and companies (including those named here) who worked to facilitate this incredible tour.
Access to these sites was a once in a lifetime opportunity for the students, providing them with an incredible experience viewing first-hand the challenges and innovative solutions required to complete such impressive geological engineering projects.
