1. Geotechnics (not only) of Switzerland Major railroad constructions Gotthard base tunnel (GBT) Bastian Bommer-Denss

2. Geotechnical problems
Major railroad constructions: Gotthard base tunnel (GBT)
Overall context
The new transalpine rail routes (NEAT - Neue Eisenbahn-Alpentransversale)
Bundesamt für Verkehr BAV
Content
Overall context
Geological context
Geotechnical problems
Costs
25. März 2017

3. Geotechnical problems
Major railroad constructions: Gotthard base tunnel (GBT)
Overall context
The new Gotthard rail link (longer, flatter and faster)
(2016/17)
(2019)
Bundesamt für Verkehr BAV
Content
Overall context
Geological context
Geotechnical problems
Costs
25. März 2017

4. Geotechnical problems
Major railroad constructions: Gotthard base tunnel (GBT)
Geological context
Gotthard base tunnel – Geological profile
AlpTransit Gotthard AG
Die Zeit 42/2010
Content
Overall context
Geological context
Geotechnical problems
Costs
25. März 2017

5. Geotechnical problems
Major railroad constructions: Gotthard base tunnel (GBT)
Geotechnical problems
Preliminary study 1992
950 m
Partially squeezing rock -> comprising sheared and folded Serizit phyllites (cataclasite)
2910 m
Extreme squeezing rock -> intensively crumbled, kakiritic mica gneisses, mica slates and mica phyllites m
Liquid rock with high water pressure -> sugar-grained Dolomite
400 m
Talus material from rockfall -> unconsoli-dated rock
AlpTransit Gotthard AG
Tunnel 4/2004
Content
Overall context
Geological context
Geotechnical problems
Costs
25. März 2017

6. Geotechnical problems
Major railroad constructions: Gotthard base tunnel (GBT)
Geotechnical problems
Sedrun Part-Section
AlpTransit Gotthard AG
Tunnel 4/2004
Content
Overall context
Geological context
Geotechnical problems
Costs
25. März 2017

7. Geotechnical problems
Major railroad constructions: Gotthard base tunnel (GBT)
Geotechnical problems
Sedrun Part-Section
TZM North
Geotechnically trickiest section
1 km long, with 1000 m overburden
AlpTransit Gotthard AG
Tunnel 4/2004
Content
Overall context
Geological context
Geotechnical problems
Methode
Vorgehen
Ergebnisse
Zeitplan
25. März 2017

8. Geotechnical problems
Major railroad constructions: Gotthard base tunnel (GBT)
Geotechnical problems
Sedrun Part-Section
Geol. exploration
Five exploratory drillings
One penetrated the entire TZM
=> Intensively crumbled, kakiritic micas
AlpTransit Gotthard AG
Tunnel 4/2004
Content
Overall context
Geological context
Geotechnical problems
Costs
25. März 2017

9. Geotechnical problems
Major railroad constructions: Gotthard base tunnel (GBT)
Geotechnical problems
Sedrun Part-Section
Information about the danger patterns
Triaxial tests
Extreme squeezing behaviour
capacity to close the cavity
Loosening phenomena and caving behaviour at the face and on the fringe
Securing the cavity
Tagungsband Swiss Tunnel Congress 2008
Tunnel 4/2004
Content
Overall context
Geological context
Geotechnical problems
Costs
25. März 2017

10. Geotechnical problems
Major railroad constructions: Gotthard base tunnel (GBT)
Geotechnical problems
Sedrun Part-Section
Cavity support
to resist large permissible deformations of up to 70 cm radially
Deformable steel arches (double ring) every 1 m, 66 cm or 33 cm
Anchoring system with radial anchors of up to 12 m in length
Tunnel 4/2004, Swiss Tunnel Congress 2008, IUT’ 02
Content
Overall context
Geological context
Geotechnical problems
Costs
25. März 2017

11. Geotechnical problems
Major railroad constructions: Gotthard base tunnel (GBT)
Geotechnical problems
Sedrun Part-Section
Choice driving method
Conventional driving with tunnel excavators (shovels, picks and ripper teeth)
On account of squeezing rock
AlpTransit Gotthard AG
IUT’02
Content
Overall context
Geological context
Geotechnical problems
Costs
25. März 2017

12. Geotechnical problems
Major railroad constructions: Gotthard base tunnel (GBT)
Geotechnical problems
Situation 2010
950 m
Partially squeezing rock -> comprising sheared and folded Serizit phyllites (cataclasite)
Difficult Intschi zone crossed without problem with an average daily advance of 6 m by TBM (6/2004)
1000 m
Extreme squeezing rock -> intensively crumbled, kakiritic mica gneisses, mica slates and mica phyllites
Squeezing Rock Conditions Successfully Overcome: breakthrough took place nine months ahead of schedule (TZM) (10/2007) m
Liquid rock with high water pressure -> sugar-grained Dolomite
Piora syncline definitively and successfully mastered with an average daily advance of 10 to 12 m by TBM. The rock was stable. No deformations and no water. (2/2009)
400 m
Talus material from rockfall -> unconsoli-dated rock
Firsts breakthrough in the GBT with special driving method (11/2002)
AlpTransit Gotthard AG
Tunnel 4/2004
Content
Overall context
Geological context
Geotechnical problems
Costs
25. März 2017

13. Geotechnical problems
Major railroad constructions: Gotthard base tunnel (GBT)
Geotechnical problems
Unexpected 2003
Fault zone: Squeezing rock in Faido multifunction station (1/2003)
Investigating fault zone
Redisposition of the FMS
24 months delay
additional costs of 500 million CHF
AlpTransit Gotthard AG
Tunnel 4/2004
Content
Overall context
Geological context
Geotechnical problems
Costs
25. März 2017

14. Geotechnical problems
Major railroad constructions: Gotthard base tunnel (GBT)
Costs
The Costs of the AlpTransit Gotthard Project (2010)
Total costs: CHF billion (Gotthard route with the Gotthard and Ceneri Base Tunnels)
AlpTransit Gotthard AG
Kurzfassung NEAT-Standbericht 2010 / I
Content
Overall context
Geological context
Geotechnical problems
Costs
25. März 2017

15. Thank you! Questions?