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EOSC433EOSC433::
Geotechnical Geotechnical Engineering Engineering
Practice & DesignPractice & Design
Lab 1: Case Histories Lab 1: Case Histories --Campo Campo VallemaggiaVallemaggia & & GotthardGotthard Base TunnelBase Tunnel
1 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Campo Campo VallemaggiaVallemaggia
2 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Campo Vallemaggia, CH
Geology - metamorphic gneisses & schistsMechanism – translational slide (30° SSE)Surface Area - ~ 6 km2
Total Volume - ~ 800,000,000 m3
Average Velocity - ~ 5 cm/yearMaximum Depth - ~ 300 m
2
Campo Campo VallemaggiaVallemaggia –– Integrating Data SetsIntegrating Data Sets
3 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Bonzanigo et al. (2006)
Campo Campo VallemaggiaVallemaggia –– Integrating Data SetsIntegrating Data Sets
4 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Bonzanigo et al. (2006)
3
Campo Campo VallemaggiaVallemaggia –– Slide KinematicsSlide Kinematics
5 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Bonzanigo et al. (2006)
Campo Campo VallemaggiaVallemaggia –– Deep Drainage MitigationDeep Drainage Mitigation
6 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Bonz
anig
o et
al.
(200
0)
4
Campo Campo VallemaggiaVallemaggia –– Integrating Data SetsIntegrating Data Sets
7 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
1300
1350
1400
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998Bor
ehol
e H
ead
(m)
788
788.2
788.4
788.6
788.8
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998Geo
detic
Mov
emen
t (m
)
0
1
2
3
4
Vel
ocity
(mm
/day
)
critical threshold at 1390 m
Bonz
anig
o et
al.
(200
1)
Campo Campo VallemaggiaVallemaggia –– Mitigation OptionsMitigation Options
8 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Eber
hard
t et
al.
(200
6)
5
Campo Campo VallemaggiaVallemaggia –– Mitigation ResultsMitigation Results
9 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
1300
1350
1400
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998Bor
ehol
e H
ead
(m)
788
788.2
788.4
788.6
788.8
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998Geo
detic
Mov
emen
t (m
)
0
1
2
3
4
Vel
ocity
(mm
/day
)
drainage adit opened
critical threshold at 1390 m
Bonz
anig
o et
al.
(200
1)
Campo Campo VallemaggiaVallemaggia –– Mitigation ResultsMitigation Results
10 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
-600
-500
-400
-300
-200
-150
-100
-50
Vertical component1993-94
mm/year
-600
-500
-400
-300
-200
-150
-100
-50
Total settlement with drainage
1995-1998
mm
… geodetically measured surface displacements showing down-slope displacements before deep drainage, and the development of a settlement trough (i.e. consolidation) after deep drainage.
BEFORE Drainage AFTER Drainage
Bonzanigo et al. (2000)
6
Campo Campo VallemaggiaVallemaggia –– Mitigation OptionsMitigation Options
11 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Campo Campo VallemaggiaVallemaggia –– Coupled HCoupled H--M M AnaysisAnaysis
12 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
0.00
0.50
1.00
1.50
20000 60000 100000
Time Steps
Pore
Pre
ssur
e (M
Pa)
adit level
20 m above adit
40 m above adit
60 m above adit
0.00
0.50
1.00
1.50
20000 60000 100000
Time Steps
Pore
Pre
ssur
e (M
Pa)
adit level
20 m above adit
40 m above adit
60 m above adit
drainageadit
opened
Eberhardt et al. (2006)
7
Campo Campo VallemaggiaVallemaggia –– Coupled HCoupled H--M M AnaysisAnaysis
13 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
0.01
0.10
1.00
10.00
20000 60000 100000
Time Steps
X -
Dis
plac
emen
ts (m
)
without pore pressures (i.e. dry slope)
without drainage adit
with drainage
aditdrainage adit
openedCampo Vallemaggia:Distinct-element models suggest that very little drainage is required (approximately 10 l/s) to significantly reduce pore pressures and to stabilize the slope.
Deep Drainage:Fracture permeability corresponds to low storativities, therefore large water inflows through drainage are not necessary to achieve significant reductions in head.
Tunnelling in SwitzerlandTunnelling in Switzerland
14 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
200734.6Loetschberg (CH)
199450.5Chunnel (ENG-FR)
198853.9Sei-kan (Japan)
2012*57.1Gotthard Base (CH)
Completion Date
Length(km)
Tunnel
WorldWorld’’s Longest Transportation Tunnelss Longest Transportation Tunnels
#30 Mount MacDonald (CAN) @ 14.6 km#43 New Cascade (USA) @ 12.5 km
Canada = 5 rail tunnels > 2 km USA = 4 rail tunnels > 2 km
Switzerland = 42 rail tunnels > 2 km
Gotthard Road Tunnel (CH) = 16.9 km
8
Tunnelling in SwitzerlandTunnelling in Switzerland
15 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Canada = 5 rail tunnels > 2 kmUSA = 4 rail tunnels > 2 km
Switzerland = 42 rail tunnels > 2 km
200734.6Loetschberg (CH)
199450.5Chunnel (ENG-FR)
198853.9Sei-kan (Japan)
201257.1Gotthard Base (CH)
Completion Date
Length(km)
Tunnel
WorldWorld’’s Longest Transportation Tunnelss Longest Transportation Tunnels
#30 Mount MacDonald (CAN) @ 14.6 km
Gotthard Road Tunnel (CH) = 16.9 km
Estimated Costs:
$7 Billion CDN
$4 Billion CDN
Financing:
10% Oil Tax 15% Loans55% Heavy Vehicle Tax20% 1% increase in VAT
AlpTransitAlpTransit Base TunnelsBase Tunnels
16 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
In 1994 the Swiss voted an alpine protection article into the Swiss constitution. This forbade the expansion of capacity on transit roads in alpine regions and obliged the government to shift heavy goods traffic from road to rail. Accordingly, voters approved the “Alptransit” project to build new tunnels through the Gotthard and the Lötschberg, and to charge heavy vehicles fees that ensure they pay for the cost they cause to society.
9
Reasons for Base TunnelsReasons for Base Tunnels
17 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Increasing Population Demands & Commercial Traffic- The Gotthard Road Tunnel, is the
main north-south route through the Alps, between Italy and Switzerland.
- 18,000 vehicles/day pass through the Gotthard Road Tunnel.
SafetySafety
Gotthard Road Tunnel Fire (2001) – 11 people killed
PollutionPollution
Drivers going through the Gotthard Road Tunnel inhale as many pollutants as if they smoked up to eight cigarettes.
AlpTransitAlpTransit Base TunnelsBase Tunnels
18 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
10
AlpTransitAlpTransit Design SpecificationsDesign Specifications
19 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
2000 2005 2010 2015 2020 2025
2000 Lötschberg 2007
2000 Gotthard 2012
2006 Zimmerberg 2013
2006 Ceneri 2016
2011 2016
2007 2011
Neat
AusbautenSt. Gallen – Arth-Goldau
VerbindungZürichsee – Gotthard
LLöötschbergtschberg Base TunnelBase Tunnel
20 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Drill & Blast
TBM
Length = 34.6 km Total tunnel system = 88.1 km Distance between parallel tubes = 40 m Gradient: 3‰ (north), 11‰ (south) Elevation, Frutigen north portal 776.5 m Elevation, Raron south portal 654.2 mExcavated material = 16 million tonnes
80%80%
20%20%
11
LLöötschbergtschberg Base Tunnel Base Tunnel –– Geological PrognosisGeological Prognosis
21 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Loew
et
al.
(200
0)
LLöötschbergtschberg Base Tunnel Base Tunnel –– Geological ChallengesGeological Challenges
22 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
The path of the Lötschberg passed under the Gästern Valley, 200 m below the valley floor. It was estimated that the alluvial sediments extended 100 m below surface leaving 100 m of strong limestone to form the roof of the tunnel.
Buried Valleys: burial is the consequence of glacial down cutting and alluvial deposition. Buried valleys are a major concern in tunnelling as they are often deep (!!), with unknown thicknesses, and filled with water saturated sediments under high water pressures.
In actuality, the buried valley reached depths of more than 185 m. By July 24, 1908, the tunnel had advanced such that only a thin wall of rock divided the working-face from the buried valley. Within seconds of that morning’s blast, 40,000m3 of water saturated sediments swept into the tunnel killing 25 men and filling the tunnel for a distance 1.25 km.
12
LLöötschbergtschberg Base Tunnel Base Tunnel –– Geological ChallengesGeological Challenges
23 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Karst:
Given the porous nature of karst, large volumes of water and a high risk of water ingress was expected over a section about 3 km long. It was constantly necessary to carry out preliminary boring in order to discover whether any large, water-filled karstsink-holes might endanger the tunnel driving operations.
1.5m
GotthardGotthard Base TunnelBase Tunnel
24 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Length = 57 km
Sedrun shaft = 800 m
Distance between parallel tubes = 40 m
Excavated material = 24 million tonnes
13
GotthardGotthard Base Tunnel Base Tunnel –– Geological PrognosisGeological Prognosis
25 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Loew
et
al.
(200
0)
GotthardGotthard Base Tunnel Base Tunnel –– Geological ChallengesGeological Challenges
26 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Geologic Unit Potential
Key Hazard Tectonic
Unit Max. Length
Cataclastic Faults High pressure water inflow.
Crystalline Massifs, Penninic Gneisses
∼100 @ 5m
Weak Rocks (Phillites, Schists, Cataclasites)
Strongly squeezing ground.
Crystalline Massifs 1.3 km
Granites Rockburst. Crystalline Massifs >14 km
Sugar Grained Dolomites
Water saturated debris inflow, cohesionless rock.
(Par)autochthonous Triassic Sediments
∼200 m
Loew
et
al.
(200
0)
The first Gotthard rail tunnel was constructed between 1872-1882, and cut the travel time from Zurich to Milan from 27 to 5.5 hours. However, 310 men died and 877 were incapacitated during construction of the 14.9 km tunnel. Numerable challenges and harsh conditions were encountered, many of which were augmented by the equally harsh contract signed by the tunnel designer Louis Favre .
14
GotthardGotthard Base Tunnel Base Tunnel –– Geological ChallengesGeological Challenges
27 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Lützenkirchen (2003)
Zang
erl e
t al
.(20
06)
Laws et al. (2003)
Granitic Fault Rocks Aar Massif(σ3=5MPa)
GotthardGotthard Base Tunnel Base Tunnel –– Geological ChallengesGeological Challenges
28 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Loew et al. (2000)
Fault zones may form highly permeable conduits for groundwater, leading to tunnel inflows. Encountering large quantities of water may lead to flooding of the excavation, especially if there is no outlet for the water to drain to.
15
GotthardGotthard Base Tunnel Base Tunnel –– Geological ChallengesGeological Challenges
29 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
GotthardGotthard Base Tunnel Base Tunnel –– Geological ChallengesGeological Challenges
30 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
The tunnel will cross the Triassic Piora Zone, a highly weathered and fractured aquifer under high hydraulic pressure. Based on exploratory drilling, the tunnel will luckily pass ~250 meters below the base of the aquifer through unweathered and unfractured dolomite/ anhydrite-sequences.
16
GotthardGotthard Base Tunnel Base Tunnel –– Other ChallengesOther Challenges
31 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
More than 13 million m3 of waste rock will be generated, leading to environmental issues as to where to put it. At the same time, the extraction of gravel resources for concrete in the Swiss midlands is becoming more difficult. The solution, therefore, is to specially break, sort & wash the waste rock so that it can be used for concrete aggregate.
Given that tunnel overburden will exceed 2000m, temperatures as high as 45°C are projected. In addition, silicosis, an incurable disease of the lungs, caused by the unprotected respiration of quartz dust presents a potential hazard to workers. Ventilation designs must account for both factors to ensure worker safety.
GotthardGotthard Base Tunnel Base Tunnel –– Unexpected ChallengesUnexpected Challenges
32 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Subsidence above old mine workings in the U.K.
Land subsidence due to extraction of large volumes of fluids from 1925 and 1977 in San Joaquin Valley, California.
Ground Collapse Consolidation
17
GotthardGotthard Base Tunnel Base Tunnel –– Unexpected ChallengesUnexpected Challenges
33 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
“Poison ratio” effect
∆σn´= ∆σn - αf∆pnormal deformation(i.e. closure)
Zang
erl et
al.
(200
3)
GotthardGotthard Base Tunnel Base Tunnel –– Unexpected ChallengesUnexpected Challenges
34 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
key dams
18
GotthardGotthard Base Tunnel Base Tunnel –– Unexpected ProblemsUnexpected Problems
35 of 35 Dr. Erik Eberhardt EOSC 433 (Term 2, 2005/06)
Zang
erl e
t al
.(20
06)