Engineering Joint Venture Gotthard Base Tunnel South
NFF – Norsk Forening for Fjellsprengningsteknikk 2016 „TBM Applications“
St. Gotthard Railway TunnelExperience versus planning, lessons learned
M.Sc. Thomas JeselAmberg Engineering Ltd., Regensdorf, Switzerland
Engineering Joint Venture Gotthard Base Tunnel South
Engineering Joint Venture Gotthard Base Tunnel South
Tunnel SystemNFF, Bergen, Norway, June 6-7 2016
STC (Swiss Tunnel Congress) www.alptransit.ch
Engineering Joint Venture Gotthard Base Tunnel South
Geological Longitudinal Section
Aar Massife CZ
TZM
UG
Z Gotthard-Massife
Penninic gneiss zoneP
ioraGeolog.
formation
Portal Erstfeld Amsteg Sedrun Faido Portal Bodio
NFF, Bergen, Norway, June 6-7 2016
Engineering Joint Venture Gotthard Base Tunnel South
Excavation MethodNFF, Bergen, Norway, June 6-7 2016
Engineering Joint Venture Gotthard Base Tunnel South
TBMNFF, Bergen, Norway, June 6-7 2016
4 Herrenknecht TBM Open gripper shield Length
TBM: 26 mBack-up: 450 m
Cutter headDiameter: 9.43 mShifted, max: 9.53 mWeight: 240 t
Discs: Number: 66Diameter: 17’’
Engineering Joint Venture Gotthard Base Tunnel South
Experience, FaidoNFF, Bergen, Norway, June 6-7 2016
Requirements Cutter head wear Water inflow Rock burst Squeezing rock Blocked TBM
Engineering Joint Venture Gotthard Base Tunnel South
Requirements INFF, Bergen, Norway, June 6-7 2016
Reduced flexibility Small areas where support
can be applied Requirements sometimes
contra dictionary Set right focus to get right TBM! Wrong focus - wrong TBM
Engineering Joint Venture Gotthard Base Tunnel South
Requirements IINFF, Bergen, Norway, June 6-7 2016
Detailed description of geology Most probable geology Hazard scenarios Set right focus Optimize TBM for project
Worst case geology Hazard scenarios Feasibility check Action plan Must be feasible
Engineering Joint Venture Gotthard Base Tunnel South
Cutter head wear INFF, Bergen, Norway, June 6-7 2016
Abrasivity with Cherchar index Tender design: CAI 2.8 Medelser Granite CAI 4.4 Lucomagno Gneiss CAI 3.4
Medelser granite
Lucomagno Gneiss
Engineering Joint Venture Gotthard Base Tunnel South
Cutter head wear IINFF, Bergen, Norway, June 6-7 2016
Instable face Not all discs at face Reduced face pressure Reduced cutting speed Blocks at the face Cutter head as crusher Rolling blocks hits the disks
Engineering Joint Venture Gotthard Base Tunnel South
NFF, Bergen, Norway, June 6-7 2016
Cutter head wear III
CAI much higher than prognosis Damaged Disks due to blocks Often longer maintenance shifts
(less time to excavate) Reduced pressure due to instable face Determinating for advance rate
Engineering Joint Venture Gotthard Base Tunnel South
Water inflow INFF, Bergen, Norway, June 6-7 2016
Water pressure up to 200 bar Probe drillings require preventer
(in sensitive areas) Needs detailed specification in
tender docs 1:1 tests on site recommended
before entering critical zone Works well for both percussion
and core drillings
Engineering Joint Venture Gotthard Base Tunnel South
Water inflow IINFF, Bergen, Norway, June 6-7 2016
Water inflow initial max 100 l/s Ascending tunnel 600 mm drainage pipe No problem But 48°C! Cooling system limited Reduced working hours Frequent pauses required Reduced advance rate
Engineering Joint Venture Gotthard Base Tunnel South
Water inflow IIINFF, Bergen, Norway, June 6-7 2016
Drained tunnels cause settlements at surface Even in rock! Valleys open or close – depending where they
are situated on the settlement curve Can be critical for Hydropower dams (opening) Simulation and prediction very demanding Expert panel very helpful No measures from the tunnel Monitor the dam, lower the water, repair
Engineering Joint Venture Gotthard Base Tunnel South
Rock burst INFF, Bergen, Norway, June 6-7 2016
Difficult to predict Without warning – suddenly! Rock support cannot prevent
rock burst But must protect staff
TBM helps! Absorbe kinetic energy Not easy to classify,
subjective Code of classification Potential measures
Engineering Joint Venture Gotthard Base Tunnel South
Rock burst IINFF, Bergen, Norway, June 6-7 2016
Engineering Joint Venture Gotthard Base Tunnel South
NFF, Bergen, Norway, June 6-7 2016
Squeezing rock I
Started with Steel arches androck bolts and shotcrete
Soon deformations (30cm) Shotcrere destroyed Steel arches plastified
Engineering Joint Venture Gotthard Base Tunnel South
NFF, Bergen, Norway, June 6-7 2016
Second TBM even worse Back up was squeezed in Heave in the invert Reconstruction of the invert
still under the TBM
Squeezing rock II
Engineering Joint Venture Gotthard Base Tunnel South
NFF, Bergen, Norway, June 6-7 2016
TBM got through – at the end Intensive back calculations Neu loads, new design Tunnel redone on 400 m
Squeezing rock V
Engineering Joint Venture Gotthard Base Tunnel South
NFF, Bergen, Norway, June 6-7 2016
D&B in this area had less problemsRock support can be installed faster
Distance between tunnels importantOptimisation process
Implementation of shotcrete in L1 has to be avoided, but worked well if necessary
Styrofoam elements worked well to protect shotcrete
Inclined cross passages allowed to redo the tunnels without interrupting the TBM
Squeezing rock VI
Engineering Joint Venture Gotthard Base Tunnel South
NFF, Bergen, Norway, June 6-7 2016
Blocked TBM I
First machine passed Some over brake Second machine got stocked Several attempts with backing
and restart were not successful 1’100 m spiles installed Voids filled up with 48 m3
concrete and 47 m3 grout
Engineering Joint Venture Gotthard Base Tunnel South
NFF, Bergen, Norway, June 6-7 2016
Blocked TBM II
Still not successful A lot of material was taken
out without any progress Massive cavern above the
tunnel Extensive probe drilling
Engineering Joint Venture Gotthard Base Tunnel South
NFF, Bergen, Norway, June 6-7 2016
Blocked TBM III
Stabilize loos material Grouting campaign Counter heading
Engineering Joint Venture Gotthard Base Tunnel South
NFF, Bergen, Norway, June 6-7 2016
Blocked TBM IV
Action plan was very helpful, reduced reaction time significantly
Expert panel was important Close collaboration and clear
communication was crucial
Decision need to be taken fast, immediately at the face
Willingness to solve the problem compulsory
Engineering Joint Venture Gotthard Base Tunnel South
Advance rate INFF, Bergen, Norway, June 6-7 2016
Expectations from design phase: 2.33 m/h
Ost WestPenetration mm/U 8.28 8.46Netto advance rate m/h 2.51 2.64
Engineering Joint Venture Gotthard Base Tunnel South
Advance rate IINFF, Bergen, Norway, June 6-7 2016
Joint and foliation angle important influence
Penetration around 10 mmwhile perpendicular
Drops down to 70% while flat
Engineering Joint Venture Gotthard Base Tunnel South
Advance rate IIINFF, Bergen, Norway, June 6-7 2016
m/d Design Ost west
10.8 13.0 12.8
‐ 20% 18%
7.4 9.6 9.3
‐ 30% 25%
8.9 9.3 8.9
‐ 4% 0%
12.2 10.0 10.5
‐ ‐18% ‐14%
Erstfeld
Amsteg
Faido
Bodio
Engineering Joint Venture Gotthard Base Tunnel South
Lessons learned INFF, Bergen, Norway, June 6-7 2016
Optimize TBM for most probable geology – set right focus
Make sure, that TBM can handle worst case (not necessarily efficient)
Open gripper TBM was right decisionFlexibility was needed
Shotcrete in L1 was necessary and feasible, main shotcrete in L2
Rock bolts in L2 were not used. Bolts are needed as close to the face as possible
Engineering Joint Venture Gotthard Base Tunnel South
Lessons learned IINFF, Bergen, Norway, June 6-7 2016
A continuous probe drilling from the TBM was very useful (low cost, no time)
In such difficult geology it is inevitable to have competent staff on site (contractor, designer bust also client)
Decisions need to be taken fast, to keep TBM running
Logistic is important. Keep other activities as low as possible
TBM produces a lot of data. Data evaluation needs a clear concept to get significant results
Engineering Joint Venture Gotthard Base Tunnel South
Final remarkNFF, Bergen, Norway, June 6-7 2016
Main problem: Communication!
