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Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Underground Excavation Design
I
Alfred Zettler
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Underground Excavation Design
Name: Alfred Zettler
Email: a.zettler@zconsult.at
Lessons (suggestion):
10.11.2015 3 pm HS 4
24.11.2015 3 pm HS 4
15.12.2015 3 pm HS 4
12.01.2016 3 pm HS 4
26.01.2016 3 pm HS 4
Written exam:
26.01.2016 5 pm HS 4
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Underground Excavation Design
You learned a lot about techniques, materials, calculation methods, ect. in engineering design.
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Underground Excavation Design
What makes underground excavation design different to other fields of
engineering design?
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Underground Excavation Design
Examples:
� Reinforced concrete
� Steel constructions
� Wood constructions
� Compound materials
(steel and concrete, or wood and steel, ect.)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Underground Excavation Design
Rock mechanics:
The material is not determined by the designer!
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Differences to other fields of engineering?
The main difference to other engineering disciplines is that in rock mechanics the material is pre-determined, e. g.:
Steel, concrete, wood, compound material.
The material is determined.
It is possible to choose material with different characteristics.
Tests are easy to perform and to determine.
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Is it possible to influence the rock
mass around an underground opening?
There are chances to influence the rock mass behaviour around an underground opening:
Shape, Orientation,
Support Measurements
To figure out the best shape and the best orientation is the most successful way to influence the rock mass behaviour around an underground opening.
The target of the lesson is to learn about the influence of the shape, the orientation and support measurements on rock.
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Discontinuities
(Photo: Hoek Rock Engineering, course notes)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Labor Tests
Uniaxial Compressive Test
Speci
fic
Explo
sive
Consu
mption k
g/m
³
(from: Thuro & Plinninger, 2007))
Uniaxial Compressive Strength MPa
Speci
fic
Explo
sive
Consu
mption k
g/m
³
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Specific Explosive
Consumption [kg/m³] =
= 0,393 + 0,116 UCS [MPa]]
(from: Thuro & Plinninger, 2007))
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Drilli
ng V
elo
city
m
/min
Uniaxial Compressive Strength MPa
(from: Thuro & Plinninger, Geologisch-geotechnische Grundlagen der Gebirgslösung im Fels 2006)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Drilling Velocity [m/min] =
= 5,42 - 0,7 ln UCS [MPa]
(from: Thuro & Plinninger, 2007))
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Drill
Bit L
ifetim
e m
/bit
Cerchar Abrasiveness Index (CAI)(from: Plinninger, 2009, Figure 9, Page 44)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Drill Bit Lifetime [m/bit] =
= 3066,3 EXP(-0,452 CAI [-])
(from: Plinninger, 2009, Figure 9, Page 44)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
How do we influence the rock mass?
Often there is no chance to optimize the orientation, then it is necessary to optimise shape and support measurements.
In a few cases we finally have to accept the rock mass and the rock mass behaviour and we have to deal with it.
Fore example: Rock burts
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Rockburst in an underground mine
(Photo: Hoek Rock Engineering, course notes)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Rockburst at Gothard base tunnel
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
How do we influence the rock mass?
But often we do not use the possibilities to influence the rock mass behaviour.
We make a poor blasting.
Often a gentle treatment of the rock will help us to minimize rock failures and therefore minimise the costs for tunnelling.
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Poor blasting
(Photo: Hoek Rock Engineering, course notes)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Good blasting
(Photo: Hoek Rock Engineering, course notes)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Achraintunnel road header
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
How do we influence the rock mass?
In the following you see different roof failures.
Most of them are wedge failures.
That means that wedges are falling out due to gravity.
In many cases we must use systematic support measurements to avoid rock mass failure for example wedge failure in the tunnel roof.
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example
(Photo: Hoek Rock Engineering, course notes)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example
A wedge failure in the roof of the top heading of the Rio Grande tailrace tunnel (Photo: Hoek Rock Engineering, course notes)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example
A 6m wide heading driven ahead of the tunnel to permit pre-reinforcement of potential unstable wedges in the roof (Photo: Hoek Rock Engineering, course notes)
Tunnel shape
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example Ambergtunnel
Wedge failure in the roof of the top heading
Wedge forms the tunnel shape
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example Ambergtunnel
Wedge failure in the roof of the top heading
Wedge forms the tunnel shape
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example Ambergtunnel
Wedge failure in the roof of the top heading
Wedge forms the tunnel shape
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
How do we influence the rock mass?
Orientation (if it is not determined)
Shape of the tunnel
Excavation Stages
Support measurements
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example
(Foto: Hoek Rock Engineering, course notes)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example
A view of the 25 m span Rio Grande power cavern during excavation of the lower bench (Photo: Hoek Rock Engineering, course notes)
Pick- up
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example
Partially completed 20 m span, 42.5 m height underground powerhouse cavern of the NathpaJhakri Hydroelectric Project in HimachelPradesh, India. The cavern is approximately 300m below the surface.(Photo: Hoek Rock Engineering, course notes)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
How do we influence the rock mass?
Support measurements
shotcrete
rock bolts
wire mesh
steel sets
forepoles
ect.
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Support MeasurementsTunneling Class6/4,43 (top heading)5/2,42 (bench)1/1 (invert)
steel set 70/20/30
shotcrete ds=20cm
1 layer wire meshAQ50 rock side
1 pice rock bolt SN-Type 250kN l=3m
shotcrete ds=15cm
7,5 pices rock boltSN-Typ 250kN l=6m
1 layer wire meshAQ50 rock side
1 layer wire meshAQ50 rock side
7,5 pices rock boltSN-Typ 250kN l=6m
11 pices forepoles not cement groutet l=3m e=35cm
tunnel faceshotcrete ds=5cm
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Achraintunnel shotcrete escape tunnel
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Tauerntunnel Support measurements
Underground Excavation Design
Rockbolt SN-type (Store-Norfors)
first used in Store-Norfors cole mine
Part 1 Tunnel Design Introduction Alfred Zettler
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Tunnel face instability Tunnel Steinhaus
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Chienberg Tunnel Swisserland
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Chienberg Tunnel Swisserland
Crater due to tunnel face instability
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example
(Photo: Hoek Rock Engineering, course notes)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example
(Photo: Hoek Rock Engineering, course notes)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example
Installation of sliding joint top hat section steel sets immediately behind the face of a tunnel behind advanced through very poor quality rock.
(Photo: Hoek Rock Engineering, course notes)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example: Spiling
Spiling in very poor quality, clay-rich, fault zone material(Photo: Hoek Rock Engineering, course notes)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Tauerntunnel loose gravel
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Tauerntunnel loose gravel
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example Strenger Tunnel (high deformations)
Damping elements
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example Strenger Tunnel (high deformations)
Deformed damping elements
Undeformed damping elements
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example Strenger Tunnel (high deformations)
Deformed damping element
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example
Cables and shotcrete were used to support the roof of the power cavern in the Mingtan Pumped Storage Project in Taiwan. (Photo: Hoek Rock Engineering,
course notes)
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Trying to understand the rock mass behaviour
Investigations
� Field Investigations (e. g. geological field mapping, physical methods, etc.)
� Laboratory Investigations
� Numerical Investigations
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example Cern
ChambersUX15: Span 35m
Heigth 42 mLength 56 m
USA15: Span 22 mHeigth 17 mLength 63 m
ShaftsPX16:
Diameter 13 mPX14:
Diameter 18 m
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example Cern different excavation stages
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example Cern displacements
Underground Excavation Design Part 1 Tunnel Design Introduction Alfred Zettler
Example Cern
Vertical displacement Plastic zones
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