The Niagara Tunnel Facility Project

Cycle de conférences LCH 2013
«The Niagara Tunnel Facility Project»
presented by
Helmut Wannenmacher

The Niagara Tunnel Facility Project «NTFP»
 Introduction and Historical Development
 The NTFP: Excavation and Support
 Economical Lining Design – Passive Pre-stressed Concrete Lining
 Constructional Aspects of Passive Pre-stressed Concrete Lining
 Lessons learnt ?

Introduction and Historical Development

112°
R6300
R7220
Final Lining
Waterproofing
Shotcrete
Rock Mass 600
Arch Concrete
Invert Concrete
Introduction _ NTFP Factbox
Tunnel Length: 10’2 km
Diameter external: 14’400 mm
Diameter internal: 12’600 mm
Lining thickness: 600 mm
Flow rate: 500m3/sec
capacity : 1,6 TWh
Water pressure max.: 13 bar

Introduction
Discharge US: 3’087 m3/sec
Discharge CAN: 1’824 m3/sec
2013: 2’324 m3/sec
Residual flow:
¼ of overall energy production of
Ontario (CAN) and New York (US)
2’832 m3/sec

Introduction
Construction of a twin tunnel back in the 1950 ties

Introduction
International
Control Structure
Ice ControlGate
Gate
New
Intake
ABOVE THE
FALLS

Introduction NTFP
Cellular cofferdam with extensive grouting measures to avoid
seepage into the open pit

Sir Adam Beck I / II
and Pump Storage Reservoir
and Generating Station
Introduction NTFP _ Historical Development
1922

Diameter : 15.5 m
Support : 200 mm flanged, half circular I beams with channel lagging
in between

Bench Drilling

Bench
Complete

Concrete
Forms

The NTFP: Excavation and Support

The NTFP: Excavation and Support
• Limestone
• Sandstone
• Claystone- Queenston
Shale 60% (swelling)

 World’s largest open hard rock TBM
>> Big Becky<<
4 m 10 m 14.40 m

Rock Mass Behaviour

Economical Lining Design –
Passive Pre Stressed Concrete Lining

1. Premises of a watertight lining to avoid seepage
2. Postulation of an uncracked lining
3. Economical and sustainable allocation of lining
type
General limitations of a passive pre- stressed
concrete lining systems are:
 Internal Water pressure up to ~ 25 bar
for fair rock mass
 Good to fair/ (local weak) rock mass conditions
Economical Lining Design

KWEnzingerboden1967
KWKaunertal1963
KWFragnant1968
PSWDrakensberg1981
PSWKühtai1979
NTFP2013
Linthal2015
UWSTB2012
Linthal2015
OWDST2012
0
2
4
6
8
10
12
14
16
18
20
0 2 4 6 8 10 12
SLENDERNESS RATIO "SR" [m/m]
TENSILERINGFORCE"Z"[MN/m]
 Slenderness ratio and internal water pressure define
indirectly the effort of geotechnical measurements for
pre- stressing works
Area with high
effort of monitoring
works
Economical Lining Design _ History

Final Lining
Contact Grouting
Waterproofing
Interface Grouting
Rock mass
Shotcrete
ri
• Rock support (anchors and shotcrete)
Economical Lining Design _ Assembly of layers
• Rock mass grouting
• Installation of membrane PE-VLD
• Installation unreinforced concrete lining
• Pre- stressing final lining – high pressure
(gap membrane and shotcrete/ rock mass)
Workflow unreinforced pre-stressed concrete lining
• Contact grouting - low pressure
(gap final lining and membrane)

+prock
+pliner
+ r(ro)
tensioncompression
- r(ro)
allow. concrete
Lining stress-strain
relationship
Rock
m
ass
stress-strain
relationship
1
po.water
+prock
strain
Phase 1: Initial gap of concrete lining and rock mass
E. L. D._Analytical Graphical Design Method

32
+pliner
+ r(ro)
tensioncompression
- r(ro)
allow. concrete
relationship
1
p
+prock
+pliner
+ r(ro)
tensioncompression
- r(ro)
allow. concrete
relationship
Rock
m
ass
stress-strain
relationship
2
po.water
+prock
Rock mass stress-strain
relationship
3
po.water
Phase 2: Contact grouting
(Closure of initial gap - bedding of lining )

33
+pliner
+ r(ro)
tensioncompression
- r(ro)
allow. concrete
relationship
R
relati
2
p
+prock
+pliner
+ r(ro)
tensioncompression
- r(ro)
allow. concrete
relationship
Rock mass stress-strain
relationship
3
po.water
+prock
o.watero.water
rain
Phase 3: passive pre-stressing of lining and rock mass

34
+pliner
+ r(ro)
tensioncompression
- r(ro)
allow. concrete
relationship
+prock
+pliner
+ r(ro)
tensioncompression
- r(ro)
allow. concrete
relationship
4
po.waterpo.water
+prock
ss-strain
pi
Rock
m
ass
stress-strain
relationship
Phase 4: Pre-stress losses

35
+pliner
+ r(ro)
tensioncompression
- r(ro)
allow. concrete
relationship
+prock
+pliner
+ r(ro)
tensioncompression
- r(ro)
allow. concrete
relationship
Rock
m
ass
stress-strain
relationship
Waterproofing
stress-strain
relationship
pi
5
Rock
relations
Phase 5: Operational phase

 Constructional Aspects
of Passive Pre-stressed Concrete Lining

Constructional Aspects_Membrane
Specs waterproofing membrane:
 3 layers of a modified VLD PE
 2 additional layers of PP fleece
Detection of voids with high voltage measurements upon installation

Constructional Aspects_Grout Line

Grouting section:
grout barrier
INTAKE
OUTLET
 Total 4 grout lines per section (bay)
 Grout section consists of two grout lines
 Arch: length ~30,8 m
 Invert: length ~14,4 m
Arch
Invert
3,6 to 3,8 m
Constructional Aspects_Grout Line

40
 Direct line for filling of an initial gap
 Improved tube a manchette lines with two rubber sleeves
 Limitation of grout lines length to 15 m
 Procedure for pressure tests
Constructional Aspects_Grout Line (lessons learnt)

Low
Point
Constructional Aspects_Grouting Setup

S1
Interface
Grouting Carrier
Section n+5 Section n+4 Section n+3 Section n+2 Section n+1
Pre-Monitoring
Carrier
S6
Working
Platform
section n
S5S4S3S2
Post-Monitoring
Carrier
• Premises: Monitoring length must cover the area of influence
• Monitoring length NTFP is about 80 -100 m.
Monitoring length = area of influence
Constructional Aspects_comb. Monitoring/ Grouting Concept

Kops-Vallüla,
AUT
1948
internal 2.7m
Drakensberg,
S.A.
1979-81
internal 6.5
Amlach, AUT
1989
internal
3.3m
NTFP, CAN
2012
internal 12.6m
Constructional Aspects_Development of Monitoring Systems

Boundaries Conditions for
Development of a Laser System
Accuracy:
 Accuracy real time < 1 mm
 Accuracy static 3/10 mm
Traffic:
 no influence of ongoing traffic
(strict order)
Grout Control System:
 Interactive control of grout works
on basis of deformation measurement
Constructional Aspects_Specifications Monitoring System

FILLING
PHASE
PRESTRESSING
PHASE
Constructional Aspects_ Monitoring and Interpretation

IGS 35, radial deformation over time
-2.4
-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
08.09.201100:00
10.09.201100:00
12.09.201100:00
14.09.201100:00
16.09.201100:00
18.09.201100:00
20.09.201100:00
22.09.201100:00
24.09.201100:00
26.09.201100:00
28.09.201100:00
30.09.201100:00
time / date
radialdeformation[mm]
radial strain due to IG: - 3.8 10-4
radial deformation due to IG: - 2.4 mm
point of time: 27.09.2011
result of strain gauges
result of strain gaugesFILLING
PHASE
PRE-
STRESSING
PHASE
S2 S1
IGS 32 IGS 33 IGS 34 IGS 35 IGS 36 IGS 37 IGS 38
S4S1 S3
Development of radial deformation due neighboring grouting works

Section140, differential deformation (developed view)
Date/Time: 02.04.2012 20:40
Ovalisation: 4.00 mm
m. rad. Deformation -1.38 mm

Date/Time: 02.04.2012 23:39

Date/Time: 03.04.2012 00:40

Date/Time: 03.04.2012 01:10

Date/Time: 03.04.2012 01:45

Date/Time: 03.04.2012 02:15

Date/Time: 03.04.2012 02:46

Date/Time: 03.04.2012 03:12

Date/Time: 03.04.2012 03:40

Date/Time: 03.04.2012 04:24

Date/Time: 03.04.2012 04:57

Date/Time: 03.04.2012 05:30
Deformation of the lining due to IG:
Results Pre - Stressing
2
4
6
8 7
5
3
1
Lining 03.04.2012 05:34
interpolation of splines is based on
cubic spline interpolation method

-5.0
-4.5
-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0 5 10 15 20 25
pre-stress pressure [bar]
data
behaviour of final lining - average
behaviour of final lining - boundary range
behaviour of final lining - boundary range +/- 25%
0%
20%
40%
60%
80%
100%
0%
20%
40%
60%
80%
100%

0.0
5.0
10.0
15.0
20.0
25.0
30.0
09.09.1215:15:00
09.09.1215:30:00
09.09.1215:45:00
09.09.1216:00:00
09.09.1216:15:00
09.09.1216:30:00
09.09.1216:45:00
09.09.1217:00:00
09.09.1217:15:00
09.09.1217:30:00
09.09.1217:45:00
09.09.1218:00:00
09.09.1218:15:00
09.09.1218:30:00
09.09.1218:45:00
09.09.1219:00:00
09.09.1219:15:00
09.09.1219:30:00
09.09.1219:45:00
09.09.1220:00:00
09.09.1220:15:00
09.09.1220:30:00
09.09.1220:45:00
09.09.1221:00:00
Pressure[bar]
Flowrate[l/min]
date / time
Pressure
Pressure Test
flow rate
strain gauge

-2.5
-2.0
-1.5
-1.0
-0.5
0.0
08.09.201206.00
08.09.201209.00
08.09.201212.00
08.09.201215.00
08.09.201218.00
08.09.201221.00
09.09.201200.00
09.09.201203.00
09.09.201206.00
09.09.201209.00
09.09.201212.00
09.09.201215.00
09.09.201218.00
09.09.201221.00
10.09.201200.00
date /time
Mobile Deformation Monitoring
Strain Gauge
09.09.2012 20:46
-2.2
8
mm
mm
Date / Time
Ovalisation
Radial deformation
Mobile Monitoring Results due to IG
Start Value due to
Contact Grouting
and Filling Phase

Observation of pre-stressing losses before watering up
 Antithesis of doctrine , to be investigated by a phd study !!!!!!!!

 Lessons learnt ?

• Effective und risk minized operation of pre-stressing works due to dection in
time (spalling and overstressing may lead to damage of structure and personal)
• Full scale documentation and detection of area with insufficient pre-stressing
(Intervention)
• Amortisation of initial cost due to shortage of time for pre-stressing works.
• System is now fully developed (after 10 km) and can be rented !!!!!!!!!
ContraPro
 (Higher initial investment for
monitoring system)
 Qualified und experienced personal
necessary for set up and monitoring
 Intense work preparation
 Pre-stressed pressure tunnels work!
 Combined grouting / deformation (full
face) is the key to success
 Full face monitoring is valuable for
geotechnical monitoring and data
interpretation and documentation for
owner
 In time decision making , no delays
(costs)
Conclusion
Lessons learnt

Operation
Supervisor
Shift Engineer
Foreman
Technicans Pumps
Operator Pumps
Design & Monitoring
P.P-S.C.L.
Experienced design team
Geotechnical Eng. on site
Mechatronics
Mechatronics
Electricians
Software Engineers
Lessons learnt

further contact :
hwannenmacher@amberg.ch
Thanks for your audience.

The Niagara Tunnel Facility Project

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