Rapid_Excavation_and_Tunneling_Conference_2017_Proceedings_Lawrence.pdf

RAPID EXCAVATION
and TUNNELING
CONFERENCE 2017
PROCEEDINGS
EDITED BY COLIN A. LAWRENCE
and ANTHONY DEL VESCOVO
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RAPID EXCAVATION and
TUNNELING CONFERENCE
2017 PROCEEDINGS
EDITED BY COLIN A. LAWRENCE
and ANTHONY DEL VESCOVO
PUBLISHED BY THE
SOCIETY FOR MINING, METALLURGY & EXPLORATION
Copyright © 2017 Society for Mining, Metallurgy & Exploration. All rights reserved.
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On the Cover: Photo of “Bertha,” the 17.45-meter EPB for the SR99 Bored Tunnel in
Seattle.
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iii
Contents
Preface.............................................................................................................................xi
Executive Committee..................................................................................................... xiii
Session Chairs...............................................................................................................xiv
International Committee..................................................................................................xv
Part 1: Pressure Face TBM I
Accomplishing Extraordinary Tasks as a Machine Supplier for Metro Doha.................... 2
Karin Bäppler, Dirk Schrader
Innovations and Efficiency in Urban Tunnelling—A Case Study of the Eglinton
Crosstown LRT in Toronto, Ontario................................................................................ 14
Dan Ifrim, Andre Solecki, Iqbal Hassan, Paul Cott
Wear of Cutting Tools on an EPB TBM Tunneling Through Glacial Soils....................... 25
Lisa Mori, Ehsan Alavi, Brian Hagan, Michael A. DiPonio
Impact of Conditioned Soil Parameters on Tool Wear in Soft Ground Tunneling............ 37
Mansour Hedayatzadeh, Jamal Rostami, Daniele Peila
Removal of Interfering Tiebacks Using SEM in Advance of TBM Mining on the
Regional Connector Project........................................................................................... 45
Christoffer Brodbaek, Derek Penrice, Eren Kusdogan, Christophe Bragard
Port Mann Water Supply Tunnel: Lessons for the Future............................................... 58
Gregg W. Davidson, Frank Huber, Murray D. Gant
Part 2: Instrumentation and Monitoring
Material Flow Reconciliation: Risk Management for Pressurized Face Tunneling......... 72
Ulf G. Gwildis, John E. Newby
Managing Ground Control with Earth Pressure Balance Tunneling on the
Alaskan Way Viaduct Replacement Project................................................................... 82
Edward J. Cording, Jack T. Nakagawa, Justin J. McCain,
Anthony F. Stirbys, David Sowers, Jorge Vazquez, Cody Z. Painter
DC Clean Rivers Project: Geotechnical Instrumentation Programs for
Protecting Critical Infrastructures in the Nation’s Capital............................................... 99
Lei Fu, Peter Kottke, Brad Murray, Stephen Njoloma, Rafael Castro,
Moussa Wone
A Smart Disc Cutter Monitoring System Using Cutter Instrumentation Technology......109
Kamyar Mosavat
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iv Contents
Part 3: Shafts
Dugway Storage Tunnel Ground Freezing at the Shaft DST‑1: A Focus Study on the
Successful Application of Ground Freezing Around an Open Shaft Excavation.......... 120
Jim Kabat, Roberto Bono, Giacomo Pini, Ryan Sullivan
Design of the Hemphill Deep Pump Station Shafts Using Blind Bore
Drilling Techniques....................................................................................................... 131
Yong Wu, Tao Jiang, Julian Prada, Brian Jones
Hecla Mining Lucky Friday No. 4 Shaft Challenges and Possibilities........................... 140
George Sturgis, David Berberick, William Strickland,
Matthew Swanson, Eunhye Kim, Gabriel Walton
An Overview of the SR99 TBM Access Shaft, Seattle, Washington............................. 151
Phillip A. Burgmeier, Jacob Mitchell, Gregory Hauser
Gas Control in a Vertical Boring Machine Advanced Shaft in Shale............................ 160
Ryan P. Sullivan, Michael J. Schafer, Michael A. Piepenburg,
Phil Kassouf
Large Diameter and Deep Shafts: Unique Design and Construction Challenges........ 171
Raymond Blanchard, Edgardo Ross, Harald Leiendecker,
Rodolfo Aradas
Part 4: Grouting and Ground Modification I
Cellular Backfill—A Review of Some of the Basics..................................................... 182
Raymond Henn, David Crouthamel
Copenhagen Cityringen Project: Big Data to Manage Quality Control in
Megaprojects............................................................................................................... 190
Livia Cicinelli, Valerio Violo, Frank Stahl, Thomas Gronbach
Copenhagen Cityringen Project: Complex Passage and Obstacle Removal
Under Existing Metro Station....................................................................................... 202
Valerio Violo, Antonio Raschillà
Grouting and Ground Modification—Copenhagen Cityringen Project:
Compensation and Jet Grouting as Mitigation Measures for TBM Operation
Under Historical Building............................................................................................. 213
Antonio Raschillà, Valerio Violo, G. Kafantaris
The Crossing Under the Alaskan Way Viaduct............................................................ 226
Enrique Fernandez, Gregory M. Hauser, Francisco Gonzalez,
Carlos Herranz, Andrew Herten
Part 5: Hard Rock TBM
Rockbursts in TBM Tunnels—Analysis and Countermeasures.................................... 240
Gary Peach, William B. Dobbs, Bruce Ashcroft
Large-Diameter 20-Inch Disc Cutters: A Comparison of Tool Life and
Performance on Hard Rock TBMs............................................................................... 254
Stephen Smading
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Contents v
Successful Excavation of Mexico City’s Emisor Poniente II Wastewater
Tunnel—Use of a Dual-Mode, Crossover TBM in Challenging Geology..................... 261
Roberto Gonzalez, Martino Scialpi
High Cover TBM Tunneling in the Andes Mountains—
A Comparative Study of Two Challenging Tunnel Projects in Chile.............................. 269
Carlos Lang, Mark Belli, Pablo Salazar
Part 6: Conventional Tunneling
John Hart Generating Station Replacement Project—Underground Works:
Project Update and Challenges Encountered.............................................................. 284
Matt Kendall
Sewer Tunnel Excavated Under and Adjacent to Treacherous Terrain,
Including Landfills, Oil Refinery, Crowded Streets, and Significantly
Contaminated Material and Utilities............................................................................. 298
Russell Vakharia, Rosann Parachuelles
Design and Construction of the Capitol Connector Pedestrian Tunnel........................ 306
Andrew M. Stone, John Jacoby, Matt Over, Joe Schrank
Geotechnical Considerations for the ORBEEC Drumanard Tunnel............................. 317
David Neil
Part 7: Large-Span Tunnel Cavern
Design and Construction of Indianapolis Pump Station Cavern.................................. 326
Verya Nasri, Alex Varas, Michael Miller, Jose Castillo
Admiralty Station, Hong Kong: Rock Excavation and Support Challenges to
Accommodate MTR’s Two New Lines.......................................................................... 336
Harry Asche, Mike Bezzano, Scott Smith, Mark Wiltshire
Completing the Second Avenue Subway Project, New York........................................ 350
Jonalen Chua-Protacio, Richard Giffen
Permanent Lining Design for Downtown Los Angeles Cavern..................................... 358
Justin Lianides, Carlos Herranz, Derek Penrice
First Large-Diameter Hard Rock CSO Chamber in St. Louis....................................... 371
Dave Frierdich, Patricia Pride, Kevin Nelson, Clay Haynes
Part 8: Future Tunneling
Overvaal Rail Tunnel: Securing the Economic Arteries of the Rainbow Nation........... 378
Jack Muir, Hennie Gouws
California High-Speed Rail—Connecting and Transforming California—Design
Considerations for Tunnels.......................................................................................... 389
Steve Dubnewych, Steve Klein, Ofelia Alcantara, Noopur Jain,
Randy Anderson
Design of Atlanta Raw Water Supply Program............................................................. 400
Tao Jiang, Don Del Nero, Adam Bedell, Brian Jones, Ade Abon
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vi Contents
Annacis Island Wastewater Treatment Plant Tunneled Outfall System......................... 409
John Newby, Kapila Pathirage, Ken Massé
Delivery of Design, Environmental Statement, Engineering, Construction
Management of the UK’s New High Speed Railway for the 21st Century................... 420
Colin Rawlings, Nita Rabadia, Mark Howard, Richard Sturt,
David Soper, Alan Vardy
Planning and Design of the New Ashbridges Bay Treatment Plant Outfall for
the City of Toronto........................................................................................................ 438
Gary J.E. Kramer, Deborah Ross, Fiona Duckett, Justyna Kempa-Teper
Planning of the San Francisco Public Utilities Commission’s Channel Tunnel............. 453
R. John Caulfield, Art Hamid, Manfred Wong
Part 9: Pressure Face TBM II
EPB or Slurry TBM? Suffolk County, Long Island, NY, Outfall
Replacement Tunnel.................................................................................................... 466
Michael S. Schultz, Greg Sanders, Mary Anne Taylor, John Donovan
SR99 Bored Tunnel in Seattle: Performance and Challenges of “Bertha,”
the Largest TBM Ever.................................................................................................. 472
Roger Escoda, Juan Luis Magro, Jorge Vazquez
Design and Implementation of a Large-Diameter, Dual-Mode “Crossover”
TBM for the Akron Ohio Canal Interceptor Tunnel........................................................ 488
E. Comis, D. Chastka
Cutterhead Protection in a Boulder Field Using Real-Time Vibration Monitoring......... 498
Jessica Buckley, Ehsan Alavi, Brian Hagan, Michael A. DiPonio,
Mike Mooney, Nathan Toohey, Thomas Planes
EPB TBM Foam Generation........................................................................................ 509
Mike Mooney, Nils Tilton, Dhrupad Parikh, Yuanli Wu
Challenges Encountered During Tunneling on the First Street Tunnel Project............. 521
Mina M. Shinouda, Thomas Costabile, Abdul-Ghani Mekkaoui,
William P. Levy
Part 10: Risk Management
Tunneling Risk Is Down, Uncertainty Is Up—Fifty Years of Experience and
Case Studies............................................................................................................... 534
Russell Clough
Contract Packaging and Formation—Risk Informed or Ignored?................................ 540
Andy Thompson
DigIndy Tunnel System—Pleasant Run Deep Tunnel Optimization Yields
Cost Savings and Improved Level of Service.............................................................. 546
Nick Maynard, Leo Gentile, Maceo Lewis IV
Reduce Urban Tunnel Utility Relocation Risk Through Early Relocation by
Specialty Contractor.................................................................................................... 555
Gordon Evans, Carlton Ray, Tom DiLego, Justin Carl,
Steven Bealby, Aliuddin Mohammad
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Contents vii
The Importance of Collective Safety Buy-In from Project Mobilization......................... 566
Christina Lindstrom, Arthur Musisi
Part 11: Major Projects
Procurement and Delivery Strategies to Increase Competiveness on
Tunnel Projects.............................................................................................................574
Steven R. Kramer, Paul Nicholas
Design-Build Project Delivery: The Importance of Successful Coordination
Between Designer and Contractor............................................................................... 584
Mark Johnson, Martin Ellis
Construction of the Longest Road Tunnel in Mexico.................................................... 594
Hector Canseco Aragon, Miguel Angel Banuet Rodriguez
Semmering Base Tunnel: 17 Miles of SEM and TBM Tunneling Under
Challenging Conditions in Austria................................................................................ 604
Michael Proprenter, Oliver K. Wagner
Boston’s Central Artery/Tunnel Project—Lessons Learned......................................... 614
John Reilly, Fred Salvucci, David Hatem
Tunneling Challenges on the Auckland City Rail Link, New Zealand........................... 624
Tom Ireland, Bill Newns, Shu Fan Chau, Steve Hawkins
Part 12: Innovation and Technology
Game-Changing Technology for Overhead Ventilation Duct Construction in
Large-Diameter Railway Tunnel................................................................................... 638
Tse-Hung Lee, Li-Ling Chen
The Use of Saturation Diving Techniques in Support of Pressurized Tunnels............. 647
Justin Costello
Use of Infrared Technology to Detect Backfill Voids Behind Steel Lining
in Tunnels..................................................................................................................... 655
Alexander MacKinnon, Bruce Harland
Use of “Command Chair” Simulator Technology to Optimize Modern
TBM Performance........................................................................................................ 665
Steve Chorley
Metro Doha—Continuous Tunnel Belt Application for One of the World’s
Largest Infrastructural Projects (A Challenge)............................................................. 673
Marco Sonnenschein, Georg Butsch
Part 13: Tunnel Lining I
Load-Bearing Capacity of Fiber-Reinforced Concrete Tunnel Linings Under
Combined Moment-Normal Force Loading Conditions................................................ 680
Axel G. Nitschke, Erik S. Bernard
Engineered and Safe Approach to Tunnel Segment Lining Installation with
Dowelled-In Connectors on the First TBM Tunnel in Qatar.......................................... 694
Francois G. Bernardeau, Jacek B. Stypulkowski
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viii Contents
Design of Steel Fiber-Reinforced Concrete Segmental Lining for the
South Hartford CSO Tunnel......................................................................................... 706
Mehdi Bakhshi, Verya Nasri
Final Lining Design of the Ohio River Bridges East End Crossing Tunnel................... 718
Wern-ping Chen, Mohammad Tughral Shaikh, Sharma Narasimharajan,
Clement Uhring
Construction Logistics for East Side Access CM006 Manhattan
North Structures
—A Study from Queens to Manhattan.............................................. 731
Sam Lo Grasso, Roberto Adames, Lonnie Jacobs
Cost-Effective Seismic Station-Tunnel Connections on Westside Subway
Extension Project Section 1..........................................................................................741
Anthony Harding, Hisham Nofal
Part 14: Stations and Cross Passages
Cross-Passage Mining Using Different Supports in Different Grounds........................ 754
Satoshi Akai, Kenji Yamauchi, Hiroyoshi Kawasaki, Darrell Liebno,
Guido Venturini
Systematic Cross-Passage Design and Construction Planning for
Transit Tunnels............................................................................................................. 764
Peter Chou, Yue Shi, Matthew Burdick, Patrick Nicholson
Station Excavation and TBM Tunnel on Los Angeles Crenshaw Project...................... 775
Ran Chen, Jesse Salai, Ben Schatz
Third Street Light Rail Phase 2, Central Subway Stations, San Francisco, CA—
Utilization of Multiple Foundation Techniques.............................................................. 786
Albert Neumann, Kevin Bolton, Jeffrey J. Bean
Risk Reduction, Management, and Mitigation from Experience‑Based
Learning During Construction of Cross Passages, Seattle, Washington..................... 796
Sandeep Pyakurel, Walter Klary, Vojtech Gall, Nate Long, Anthony Pooley
Closing the Gap for Bogotá River Sanitation System Tunnels (Colombia)................... 809
Michael B. Gilbert, Harlem Suarez, Mahmood Khwaja
Part 15: Grouting and Ground Modification II
Leak Mitigation Grouting for New York Subway Tunnels.............................................. 822
Paul M. Gancarz, John E. Minturn, Nico J. Grobler, Deon Van Dyk
Complex Inner-City Tunnel Excavation by Means of the New Austrian
Tunnel Method in Combination with a Hyperbaric Atmosphere................................... 831
Thomas Wechner
Geologically Targeted Pre-Excavation Grouting Along the WestConnex
M5 Tunnel, Sydney, Australia....................................................................................... 839
Ulrike Pelz, Joan Casado, Harry Asche, Jack Raymer,
David Crouthamel, Scott Fidler
A Proactive Approach to Tieback Anchor De-tensioning.............................................. 852
Sean Peterfreund, Grant Finn
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Contents ix
Ground Freezing for Tunnel, Shafts, and Adits............................................................. 858
Joseph A. Sopko, Adam Curry, Bianca Messina, Stephen Njoloma
Exposing Young Engineers to Multiple Facets of Tunneling......................................... 865
Jeff Brandt, Eren Kusdogan, Nick Tabor, Dillon Tew
Part 16: Trenchless Tunneling
Paradise Raw Water Intake: Fighting the Green River..................................................874
Nicholas Joens, Matt Roberts
Dugway South CSO Relief and Conveyance Sewer, A Critical Connector.................. 881
David Mast, Karrie Buxton, Amanda Foote, Irwan Halim, Alison Schreiber
Long-Distance Microtunnelling at Toronto Pearson International Airport..................... 891
Robert Ofori, Jordan Schreiner, Marc Gelinas, Ajay Puri,
Walter Trisi, Joe Mulville
Upper Limit Microtunneling Application to Meet Dam Safety and
Operational Longevity.................................................................................................. 900
Babs Marquis, Everette Knight, Emory Chase, John Vickers,
John Arciszewski
Microtunneling in Georgian Bay Shale: Rebecca Trunk Wastewater Main,
Oakville, Ontario.......................................................................................................... 909
Paul Headland, Guadalupe Monge Fabian, Rajab Ali,
Kanchan Mohammed, Mark Bajor
Part 17: SEM/NATM
Steep Inclined SEM Excavation—The “Uphill Machine”—at London Crossrail:
Development and Application of a Safe Excavation System in Soft Ground................ 928
Rainer Antretter
Downtown Bellevue Tunnel—Concept Optimization Through Team Collaboration...... 937
Derek Penrice, Hong Yang, Chad Frederick, Jacob Coibion
Comparative Application of NATM, TBM, and RBM Technologies............................... 949
Pedro Pino Véliz, Patricia Kong Diaz
Sequential Excavation Method with Ground Freezing for DC Water’s First
Street Tunnel................................................................................................................ 960
Ivan Hee, William Bracken, Harald Cordes, Stephen Njoloma
Part 18: Difficult Ground
Design of the Fort Wayne CSO Tunnel Through Complex/Wet Rock........................... 970
Aswathy Sivaram, Mark H. Bradford, T.J. Short
Rondout West Branch Bypass Tunnel—TBM Boring in Hard Rock Against
High Water Pressure and High Water Inflows Beneath the Hudson River
in New York.................................................................................................................. 980
David Terbovic, Martino Scialpi
Innovations on West Trunk Sewer Contract 2.............................................................. 989
Jon Hurt, Jörg Riechers, Mike Ghasemi, Tony DiMillo,
Vanessa DiMillo, Ajay Puri
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x Contents
Tunneling Through a Fault Zone at West Trunk............................................................ 999
Behzad Khorshidi, Alireza Ramezani, Nik Crawford
Part 19: Tunnel Rehabilitation
Sumner Tunnel Rehabilitation.....................................................................................1010
S.C. Quinn, J. Rigney
The Arlberg Tunnel Project—A Milestone in the Austrian Efforts to Increase
Safety of the Road Tunnel Network............................................................................1019
Michael Hoellrigl, Norbert Fuegenschuh, Christoph Wanker
Large-Diameter Sliplining Under Extreme Conditions: Rehabilitating the
Oakland-Macomb Interceptor While Maintaining Service to 830,000 Customers.......1027
Curtis Rozelle, Abdul-Ghani Mekkaoui, Fritz Klingler,
Saju Sachidanandan, Sid Lockhart
Index...........................................................................................................................1039
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xi
Preface
The Rapid Excavation and Tunneling Conference (RETC) is the largest and most prom‑
inent conference on a tunneler’s calendar and is held regularly in the United States.
Over the years, its has been developed into a very successful format that attracts the
entire underground industry. Delegates attend not only from North America but from
all over the world. In recognition of its international attendance, participation in the
RETC International Committee includes 16 members.
The RETC Executive Committee extends a warm welcome to all delegates attending
the 2017 RETC in San Diego. Bill Mariucci is the conference chair this year and is ably
supported by his vice chair, Victor Romero, and the other Executive Committee mem‑
bers. The committee has been competently assisted by SME staff and their efforts are
recognized for making all the necessary arrangements and logistics in support of the
conference. The committee has also hand-selected the session chairs and meticu‑
lously chosen the authors with the aim of maintaining the high standards for which this
conference is renowned. We also acknowledge the hard work and spare time that has
been dedicated by many people behind the scenes to allow this conference to take
place. The conference would not be possible without the significant support of our
sponsors for which we are very grateful.
The three days of conference presentations include 114 papers divided into 19 ses‑
sions running on four tracks. As you might expect, the papers cover the full breadth
and depth of the tunneling business ranging across all markets in the industry. A faith‑
ful attempt has been made at grouping the presentations into sessions that have a
common theme or interest to delegates. With so many papers from both diverse and
broad cross sections of our industry, this has proved to be quite a feat. We trust that
you will find the sessions interesting and relevant.
The presentation topics support the view that our industry continues to be buoyant
across the United States. Many major projects are currently in the planning stage,
under final design, in or having completed construction, or have been in operation for
many years and are now in need of rehabilitation. You will see tunnels for many end
uses that demonstrate the versatility in application for underground project solutions.
Several projects are pushing the envelope and are considered state of the practice
for tunneling, where others continue to complete critical components of much larger
programs that will provide future resiliency, sustainability, and opportunities for growth
in the various municipalities. With the aging infrastructure of our many historic towns
and cities, the potential for going underground to address these issues has never
been greater. This fuels the continued challenge to our industry for being ever faster,
and cheaper, while maintaining or improving safety and quality. We do this by continu‑
ously looking for innovation and improvement in everything we do. It certainly is an
exciting time to be involved in, or to join, the tunneling industry. And to be successful,
we must continue to grow to meet the demands of our business. Toward that end, we
are happy to announce that we now have a robust Young Tunnel Professionals com‑
munity, members of which you may meet at the conference. Investment in our young
professionals has never been so important to our future with the current climate of the
tunneling industry.
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xii Preface
Please seize the opportunity of this RETC to network and meet other members of this
very special industry. In doing so, you’ll meet new friends and business acquaintances
who will extend the friendship of our close and very special underground community.
Enjoy the conference.
Colin A. Lawrence
Anthony Del Vescovo
Copyright © 2017 Society for Mining, Metallurgy Exploration. All rights reserved.
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xiii
Executive Committee
Chair: William S. Mariucci
Kiewit Infrastructure Co.
Vice Chair: Victor S. Romero
McMillen Jacobs Associates
Anthony Del Vescovo
Schiavone Construction Co. LLC
Michael A. DiPonio
Jay Dee Contractors, Inc.
Chris W. Dixon
Tutor Perini Corp.
Chris Hebert
Traylor Bros., Inc.
Scott Hoffman
Skanska USA Civil Northeast, Inc.
Mark C. Johnson
CH2M
Colin A. Lawrence
Mott MacDonald
Shemek Oginski
J.F. Shea Co., Inc.
Stephen C. Redmond
Frontier-Kemper Constructors, Inc.
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xiv
Session Chairs
Jeff Brandt
Traylor Bros., Inc.
Kurt Braun
L-7 Services LLC
Pierre Ciuffarin
Joe Clare
Mott MacDonald
Thomas Costabile
Skanska
Adam Curry
Moretrench
Dave Dorfman
Greg Emslie
Geoff Fairclough
Andrew Finney
CH2M Hill
Shaun Firth
CH2M Hill
Erica Fredrickson
Traylor Bros., Inc.
Rick Gomez
Gomez International, Inc.
Gregory Hauser
Dragados USA
Josh Jonasen
Traylor Bros., Inc.
Peter Kottke
Kiewit
Nate Long
Steve Maggipinto
Robert Marshall
Justin McCain
Tutor Perini
Daniel McMaster
Mott MacDonald
A.G. Mekkaoui
Bianca Messina
Skanska
Dwight Metcalf
Kiewit
Jack Nakagawa
Tutor Perini
Cody Painter
WSP | Parsons Brinckerhoff
Frank Perrone
Mott MacDonald
Mark Peterman
Kiewit
Peter Procter
Mott MacDonald
Gregory Rogoff
David Smith
Parsons Brinckerhoff
David Sowers
Washington State Department
of Transportation
Mike Stolkin
J.F. Shea Co. Inc.
Richard Taylor
Traylor Bros., Inc.
Matt Trotter
Kiewit
Darren VonPlaten
Traylor Bros., Inc.
Moussa Wone
DC Water and Sewer Authority
James Wonneberg
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xv
International Committee
Australia: Ted Nye
Mott MacDonald
Austria: Norbert Fugenshuh
Beton-und Monierbau
Canada: Rick P. Lovat
L2 Advisors, Inc.
Czech Republic: Karel Rossler
Metrostav
England: Ross Dimmock
TAM International UK Ltd.
France: Francois Renault
Vinci Construction Grand Projets
Germany: Klaus Rieker
Wayss Freitag Ingenieurbau AG
India: R. Anbalagan
LT Construction Infrastructure
Italy: Remo Grandori
SELI Societa Esecuzione Lavori Idraulici SpA
Japan: Hiro Onozaki
Obayashi
Mexico: Roberto Gonzalaz Izquierdo
Moldequipo Internacional, S.A.
New Zealand: Siegfried W. Keis
Singapore: Leslie Pakianathan
Mott MacDonald (Singapore) Pte Ltd.
Spain: Enrique Fernandez
Dragados S.A.
Sweden: Stig Eriksson
Skanska
Switzerland: Frederic Chavan
Marti Contractors Ltd.
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Pressure Face TBM I
Chairs
Jeff Brandt
Traylor Bros., Inc.
Cody Painter
WSP | Parsons Brinckerhoff
1
PART
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2
Accomplishing Extraordinary Tasks as a Machine Supplier
for Metro Doha
Karin Bäppler  Herrenknecht AG, Germany
Dirk Schrader  Herrenknecht AG, Germany
With the construction of the Metro Doha in the State of Qatar a vision is accomplished
to establish a modern, safe, efficient and integrated public transportation network.
Upon final completion of multiple phases, the network will comprise four metro lines
with a length of 216km and 100 stations. Phase 1 comprises 112km of underground
tunnels (56km twin tube tunnels) and a total of 21 Earth Pressure Balance Tunnel
Boring (EPB) machines were deployed by the four different Joint Ventures. The project
was initiated, managed and supervised by the owner Transport Authority Qatar Rail.
Phase 2 of the Doha Metro will start upon the completion of Phase 1 in 2019 (Qatar
Vision 2030). The owner placed full faith in the manufacturer’s abilities to deliver equip-
ment of high quality, state of the art standard within the given time frame. This paper
focuses on the manufacturer’s scope of delivery and on the supplier’s high standards
of quality in production, logistics and services. The report is completed by a chapter
with remarks on the manufacturer’s analysis of TBM availability on the individual tun-
nelling sections that completed tunnelling works.
INTRODUCTION
In emerging regions of the world the growth of the cities is continuing unabated. To
maintain and increase the mobility of citizens in urban cities, more extensive and effi-
cient networks of infrastructure are required. The most common and long-term design
approach is to build such infrastructure beneath the surface. Midsize cities and estab-
lished industrial nations are following this trend and are upgrading or supplementing
their existing infrastructure networks to be well prepared for the future. The Middle
East region is emphasizing the need for mobility and new very efficient infrastructure
systems are going to be built.
Qatar Rail was given the mandate to design and develop a new rail network and thus
also the Doha Metro system of which a large part is underground. Qatar Rail’s mis-
sion is to provide modern, reliable, attractive, safe and sustainable integrated railway
services. Its objectives are to deliver the metro system in time and to the desired qual-
ity in a safe and cost effective manner. The focus of this report is on accomplishing
extraordinary tasks as a machine manufacturer for the construction of the three metro
lines of Doha Metro, the Green Line, Red Line and Gold Line.
Herrenknecht became the exclusive TBM supplier and delivered 21 Earth Pressure
Balance (EPB) machines for Phase 1 of the Metro Doha. Herrenknecht group brands
also delivered comprehensive additional equipment such as 57km of tunnel, shaft
and overland conveyor belts, 474 segment moulds, 31 multi-service vehicles, rolling
stock, navigation systems and surface monitoring. In 2012 a regional subsidiary was
founded in Qatar with the main objective of supporting the client, consultants and
contractors directly and as closely as possible. Herrenknecht technically supported
the construction companies during the time of tender preparation and after contract
award. Such support was further extended with the start of tunnelling works as follows
but not limited to:
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Accomplishing Extraordinary Tasks as a Machine Supplier for Metro Doha 3
ƒ
ƒ Provision of technical advice and expertise for the TBM assembly, tunnelling,
transfer and dismantling works
ƒ
ƒ Provision of specialized technicians (engineers, mechanics, electricians,
operators, welders)
ƒ
ƒ Provision and set-up of TBM spare wear parts and logistics
ƒ
ƒ Provision of special equipment for TBM assembly, transfer and dismantling
ƒ
ƒ Supply and refurbishment of excavation tools and the support of all group
brands
ƒ
ƒ TBM lubricants
ƒ
ƒ Working visas
ƒ
ƒ Import and export of equipment, spare wear parts
DETAILED OVERVIEW OF THE TUNNELLING SECTIONS FOR THE METRO
GREEN LINE, RED LINE, AND GOLD LINE
Phase 1 of Doha Metro comprises the construction of three new metro lines: Green
Line, Red Line (North, South) and Gold Line. The metro lines comprise parallel twin-
tube tunnels excavated and lined by 21 EPB machines with shield diameters ranging
between 7.05 and 7.11 meters. The tunnel lining consists of steel fiber reinforced con-
crete elements with an internal diameter of 6.17 meters.
The Red Line starts at Al Wakra in the south and ends in Lusail in the north. The
55.42km Red Line, also known as the Coast Line, will connect the Hamad International
Airport with the City Center. The Red Line is separated into two lots, Red North
(22.79km) from Msheireb to Qatar University and Red South (32.63km) from Hamad
International Airport to Msheireb. The 33.68km Green Line connects Al Mansoura in
the east with Al Riffa in the west and is also known as the Education Line because it
passes through Education City. The 23.32km east-west Gold Line extends from Ras
Bu Abboud to Al Aziziyah.
The geological conditions in the project area are characterized by Simsima Limestone,
Midra Shale and Rus Formation. The Simsima Limestone is composed of weak to
moderately strong weathered dolomitic and chalky limestone with fissures and cavi-
ties. The unconfined compressive rock strengths vary in general between 20–50MPa
with some up to 120MPa. The Midra Shale is a weak to moderately weak, slightly
weathered and well cemented mudstone. The Rus Formation is a soft limestone,
Figure 1. Doha Metro network linking Doha’s main destinations
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4 Pressure Face TBM I
dolomitic and chalky limestone with gypsum with predicted strengths of 5 to 15MPa.
Karstic features are found throughout the country and were taken into consideration
when designing the TBMs. Due to the given gradient of the metro alignment the tun-
nels faced all three geological formations described above. Based on the subsurface
conditions in the project area the main issues for the design of the TBMs have been:
ƒ
ƒ Heterogeneous tunnelling conditions along the tunnel drives
ƒ
ƒ Tunnelling at depths between 11 to 45 meters beneath the ground water table
ƒ
ƒ High hydrostatic pressures of up to 4.5bar
ƒ
ƒ Probability of facing karstic features with possible high water inflows
ƒ
ƒ Ground water classified as very aggressive with high salt and sulphate
content
In order to reduce possible risks due to extreme variable geological conditions an
extensive ground investigation program was executed in advance of the tunnelling
works. This program comprised geotechnical field investigations, drilling campaigns
with borehole logging, pumping tests and a ground water quality study to character-
ize the geotechnical and hydrogeological conditions along and around the planned
metro network and underground metro stations. To identify possible changes in geol-
ogy during tunnelling operation the EPB Shields and cutting wheels were prepared
to install the Bore-Tunnelling Electrical Ahead Monitoring (BEAM) system to identify
these changes about 20 meters ahead of the tunnel face.
The Doha Metro contract was split in five design and build civil contracts (four sec-
tions of Tunnel Stations and one Major Station). The details about the respective
tunnelling lots are described in the following sections with focus on the TBM works.
Special technical and logistical challenges are highlighted in the following chapter that
is related to the simultaneous operation of 21 EPB TBMs.
Doha Metro, Green Line
The design and build contract was awarded to the Joint Venture of Porr (Austria),
Saudi Binladin Group (KSA) and HBK (Qatar).
For the 33.38km of tunnel construction, Herrenknecht supplied six EPB Shields
(Ø7.05m), tunnel, shaft and overland belt conveyors, 16 multi-service vehicles,
segment moulds, cooling and grouting plants and comprehensive tunnel-surface
monitoring.
Figure 2. Typical geological conditions at TBM tunnel face (picture from Red Line South)
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Four TBMs were assembled at Al Messila Station and two at Though Shaft. Along the
tunnel drives all TBMs had several intermediate breakthroughs. The machines exca-
vated in depths of 11 to 35 meters and were designed for a maximum operation pres-
sure of 4.5bar. The first two TBMs (S-846 and S-847) started excavation in September
and October 2014 for the twin tube tunnels from Al Messila Station toward Msheireb
Station. Each machine excavated and lined a section of about 4.1km with a total of
four intermediate breakthroughs. At the end of November 2015 and the beginning of
December 2015 the two machines celebrated their final breakthroughs. Best weekly
performances of up to 216 meters were achieved.
The two TBMs (S-844 and S-845) that started tunnelling in January 2015 from Al
Messila Station in opposite direction for 6.1km toward Education City Station had their
final breakthroughs in March 2016. Along this tunnel section from Al Messila Station to
Education City Station the two machines had each three intermediate breakthroughs
and a maximum performance of 212.8 meters per week was managed. The 6.5km
long twin tube drives (S-848 and S-849) from Tough Shaft to Education City Station
were characterized by one intermediate breakthrough. Weekly performances of up to
283.2 meters were achieved and both EPB TBMs finished their drives end of February
2016.
Doha Metro, Red Line South
The design and build contract was awarded to the Joint Venture of Qatar Diar-Vinci
Construction (Qatar), GS EC (Korea) and Al Darwish Engineering (Qatar).
For the 32.63km tunnel, Herrenknecht supplied five EPB Shields (Ø7.05m) and logistic
rolling stock.
The scope of the Red Line South contract comprises the design and construction of
the underground works beneath central Doha between the Msheireb Underground
Station and the New Doha International Airport (Hamad International Airport) includ-
ing five underground stations. The machines operated at depths of 11 to 35 meters
below surface and were designed for a maximum operation pressure of 4.5bar.
Two of the five TBMs were assembled at M10/11 Switchbox and the other three at
Umm Ghuwailina. Along the tunnel drives all TBMs had several intermediate break-
throughs. The two TBMs (S-860 and S-862) that were assembled at M10/11 Switchbox
Figure 3. Assembly of the first two TBMs (S-846 and S-847) of in total four TBMs at Al Messila Station
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excavated each a first section of about 3.7km toward Umm Ghuwailina before they
started with the excavation of the second 5.5km section toward the Doha International
Airport. Tunnelling of TBM S-862 was successfully completed on September 25, 2016
which also marked the total completion of 112km tunnelling works for Doha Metro
Phase 1.
The other three TBMs (S-861, S-863 and S-864) started operation from Umm
Ghuwailina. Two machines excavated the first section of about 2.5km toward Msheireb
with the second section toward Ras Bu Abboud of 2.8km. The third machine (S-864)
excavated a section of 4.3km (first 1.3km section toward M40/104 Switchbox and the
second and third sections toward Msheireb of about 1.5km each). Tunnelling works
are completed and TBM dismantling is ongoing.
Doha Metro, Red Line North
The design and build contract was awarded to the Joint Venture of Salini-Impregilo
(Italy), SK EC (Korea) and Galfar Al Misnad (Qatar).
For the 22.79km of tunnel, Herrenknecht supplied four EPB machines (Ø7.05m) and
segment moulds.
The tunnel alignment is 11 to 35 meters below surface and all machines were config-
ured to operate with maximum pressures of 4.5bar. Two machines (S-865 and S-867)
were used for the twin tube tunnels of about 3km (1st section) and 4.2km (2nd section).
The two EPBs were assembled and launched from the bottom of Al Qassar Station.
Table 1. Overview about the tunnelling sections of the six EPB Shields used for the underground sections
of Doha Metro, Green Line
No. Breakthrough TBM Station Tunnel Length (m)
1 Partial S-846 Switchbox M30/M31 624.0
2 Partial S-847 Switchbox M30/M31 627.2
3 Partial S-846 Hamad Hospital Station 640.0
4 Partial S-847 Hamad Hospital Station 652.8
5 Partial S-846 White Palace Station 403.2
6 Partial S-845 Al-Qadeem Station 2,270.4
7 Partial S-847 White Palace Station 398.4
8 Partial S-844 Al-Qadeem Station 2,270.4
9 Partial S-848 Evacuation Shaft 04 3,694.4
10 Partial S-845 Al Shaqab Station 939.2
11 Partial S-849 Evacuation Shaft 04 3,694.4
12 Partial S-844 Al Shaqab Station 948.8
13 Partial S-846 Al Bidda Station 1,670.4
14 Partial S-847 Al Bidda Station 1,648.0
15 Final S-846 Msheireb Station 745.6
17 Partial S-845 Qatar National Library Station 1,606.4
18 Partial S-844 Qatar National Library Station 1,588.8
19 Final S-848 Education City Station 2,760.0
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Two other EPBs (S-866 and S-868) excavated the first 2.3km long drive between
Corniche and Msheireb and then the 1.8km long twin tube tunnel section between
Corniche and Doha Exhibition and Convention Centre (DECC). Along the tunnel
drives all TBMs had several intermediate breakthroughs.
On February 16, 2015 the tunnel section and TBM S-868 between Corniche to Al
Diwan was flooded as a result of water ingress through the TBM screw conveyor
of about 400 l/sec. The TBM S-868 had already excavated 1,100m and had almost
reached the deepest level of the alignment between the stations (tunnel invert 35m
below GL). The JV immediately started an extensive pumping scheme and the instal-
lation of a cut-off bore pile wall with additional wells in front of the TBM. The inflow of
water was stopped and the TBM was recovered. It was found out that a big boulder
had blocked the screw conveyor discharge gate. The TBM was fully refurbished inside
the tunnel with the replacement of all electrical components, including the control
cabin, in only three months so that the TBM was able to restart on May 16, 2015 and
successfully completed the remaining tunnel section without any further problems.
Doha Metro, Gold Line
The design and build contract was awarded to the Joint Venture of Aktor (Greece),
Yapi Merkezi (Turkey), Larsen Toubro (India), STFA (Greece) and Al Jaber (Qatar).
For the 23.32km of tunnel construction, Herrenknecht supplied six EPB machines
(Ø7.05m), tunnel, shaft, and overland belt conveyors, 15 multi-service vehicles, seg-
ment moulds, cooling and grouting plants and comprehensive tunnel-surface monitor-
ing. Herrenknecht also set up a Joint Venture with Commodore for the production and
supply of the steel fiber reinforced tunnel segments. The same JV also supplied the
tunnel segments for 30km of the STEP tunnel in Abu Dhabi.
Two machines (S-920 and S-921) were assembled at Ras Bus Abboud (Airport City
Station), each excavating a section of about 4.4km toward Msheireb Station with two
partial breakthroughs. Another four TBMs started excavation at Al Sudan Station.
Two machines excavated each a section of 3.5km toward Msheireb and two EPBs
Table 2. Overview about the tunnelling sections of the five EPB Shields used for the underground
sections of Doha Metro, Red Line South
1 Partial - 1th Drive S-863 Al Doha Al Jadeda Station 704.0
2 Partial - 1th Drive S-861 Al Doha Al Jadeda Station 707.2
3 Partial - 1th Drive S-860 Al Matar Station 2,761.6
4 Partial - 1th Drive S-862 Al Matar Station 2,768.0
5 Final - 1th Drive S-864 Switchbox M40/104 1,222.4
6 Final - 1th Drive S-863 Msheireb Station 2,337.6
7 Final - 1th Drive S-861 Msheireb Station 2,331.2
8 Final - 1th Drive S-860 Umm Ghuwailina Station 916.4
9 Final - 1th Drive S-862 Umm Ghuwailina Station 913.6
10 Partial - 2nd Drive S-863 Switchbox M40/104 810.0
11 Final - 2nd Drive S-864 Msheireb Station 1,500.8
12 Final S-861 Ras Bu Abboud Station 2,790.0
13 Final S-863 Ras Bu Abboud Station 1,920.0
14 Final S-864 Msheireb Station 1,502.4
15 Final S-860 Hamad International Airport 5,381.0
16 Final S-860 Hamad International Airport 5,435.0
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excavated and lined the twin tubes of 3.7km in opposite direction toward Al Aziziyah
Station. Along the tunnel drives all TBMs had several intermediate breakthroughs.
The tunnel boring machines operated at depths of 13 to 35 meters and were designed
to operate with maximum operation pressures of up to 4.5bar.
SPECIFIC PROJECT REQUIREMENTS FOR THE METRO
GREEN LINE, RED LINE, AND GOLD LINE
The Metro Doha project is a key infrastructure project with the target of systemati-
cally building an extensive underground local public transport artery in only a few
years. A key element in the success of such a large- scale infrastructure project is the
manufacturing and delivery of the TBMs. A common factor for the construction of the
three new Metro Lines in Doha was that all 21 TBMs were purchased from the same
supplier. This had the advantage to reduce interfaces between different construction
components to a minimum and to guarantee a smooth construction process.
Table 3. Overview about the tunnelling sections of the four EPB Shields used for the underground
sections of Doha Metro, Red Line North
1 Partial - 1th Drive S-866 Al Bidda Station 1,605.0
2 Final - 1th Drive S-867 DECC Station 2,977.5
3 Final - 1th Drive S-865 DECC Station 2,971.5
4 Final - 1th Drive S-866 Msheireb Station 712.5
5 Partial - 1th Drive S-868 Al Bidda Station 1,598.9
6 Partial - 2nd Drive S-867 Katara Station 1,231.5
7 Partial - 2nd Drive S-865 Katara Station 1,236.0
8 Final - 1th Drive S-868 Msheireb Station 796.5
9 Partial - 2nd Drive S-866 West Bay South Station 747.0
10 Partial - 2nd Drive S-867 Legtaifiya Station 889.5
11 Partial - 2nd Drive S-865 Legtaifiya Station 877.5
12 Partial - 2nd Drive S-868 West Bay South Station 769.5
13 Final S-866 DECC Station 1,083.0
14 Final S-868 DECC Station 1,068.0
15 Final S-865 Trough Golf Course 2,097.0
16 Final S-867 Trough Golf Course 2,125.5
Figure 4. Gold Line, Station Souq Waqif
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The requirement from the owner, Qatar Rail, was the commitment of all partners
involved in the construction to build a modern and efficient public transportation net-
work that will be operational in time for the FIFA World Cup 2022. The German TBM
manufacturer Herrenknecht was the exclusive TBM supplier for the underground sec-
tions of the Metro Doha project and delivered 21 EPB machines that will be described
in more detail in the following.
TBM Design and Scope of Delivery of TBM Supplier
All 21 tunnel boring machines that were used for numerous tunnelling sections for the
Green Line, Red Line South, Red Line North, and Gold Line are EPB machines with
diameters between 7.05 to 7.11 meters.
The design of the cutting wheel of the EPB Shields for all four contracts was similar
with opening ratios of 32% to 38%. The cutting wheels were equipped with 17-inch
disc cutters, buckets and cutting knives to deal with the prevailing limestone forma-
tions of differing constitution.
The twin tube tunnels of Metro Doha are constructed at maximum depths of 45 meters
beneath the ground water table. The machines are designed with operating pressures
of 4 and 4.5bar according to the specific tunnelling sections. The predicted variable
geological conditions, the probability of facing karstic features, cavities and local high
water inflows were considered during tunnel excavation. The EPB Shields can be
operated in open mode, compressed air mode and in closed mode with active face
support. The machines were designed to perform—if required—radial inclined injec-
tion drillings through the shield for crown injections and horizontal injection drillings
into the face area.
Table 4. Overview about the tunnelling sections of the six EPB Shields used for the underground sections
of Doha Metro, Gold Line
1 Partial S-922 Al Joaan Station 1,261.5
2 Partial S-923 Al Joaan Station 1,267.5
3 Partial S-920 Qatar National Museum Station 2,224.5
4 Partial S-921 Qatar National Museum Station 2,221.5
5 Partial S-925 Al Waab Station 1,489.5
6 Partial S-924 Al Waab Station 1,489.5
7 Partial S-922 Al Sadd Station 654.0
8 Partial S-923 Al Sadd Station 669.0
9 Partial S-923 Bin Mahmoud Station 879.0
10 Partial S-920 Souq Waquif Station 1,186.5
11 Partial S-921 Souq Waquif Station 1,174.5
12 Partial S-925 Sport City Station 1,615.5
13 Partial S-922 Bin Mahmoud Station 892.5
14 Partial S-924 Sport City Station 1,612.5
15 Final S-925 Al Aziziyah Station 610.0
18 Final S-924 Al Aziziyah Station 620.0
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As the project site is in the city area, the
safety and protection of the residents
is of utmost importance. This required
a settlement controlled TBM opera-
tion. The chosen tunnelling technology
enables to safely control ground settle-
ments through an adequate face pres-
sure management and the immediate
support of the excavated ground with a
lining that consists of reinforced concrete
elements. As the annular gap constitutes
a structural risk with regard to the bed-
ding of the lining and subsidence at the
surface it is essential to efficiently backfill
the annular gap between the outside of
the segmental lining and the excavated
surface of the ground. The backfilling of
the annular gap stabilizes the segmental ring and preserves the natural state of stress
in the surrounding soil so that settlement can be controlled. The backfill protects also
the segments and the shield tail from ground water inflows. The backfill material is
injected through grout lines incorporated in the tailskin at the rear of the shield struc-
ture. All 21 machines used a two-component grout type to backfill the annular gap.
The two component grout consists of an A-component (cement based grout with ben-
tonite with a retarder and stabilizer) and a B-component. The B-component is an
accelerator that is typically sodium silicate.
The advantages of the two component grout are:
ƒ
ƒ Quicker stabilization of the ring
ƒ
ƒ Shorter setting times
ƒ
ƒ Optimized working times
ƒ
ƒ The processing properties and the pumpability of the two component grout
are not affected by downtimes or advancement speeds.
The first machine for Doha Metro was manufactured in Schwanau and was inspected
by HE Jassim Saif Ahmed Al Sulaiti, Qatar’s Minister of Transport, in February 2014.
Already in August of the same year tunnelling started for the first lot of Doha Metro on
the Red Line North. Only one year later all 21 machines were in action.
In addition to supplying all 21 EPB machines, the scope of delivery of the TBM supplier
for this mega project also included special solutions to support the construction com-
panies in realizing multiple tunnelling operations smoothly and reliably. The support of
the Herrenknecht Group was able to cut construction process interfaces by delivering
several major packages from its group companies with navigation systems from VMT
GmbH, belt conveyors from H+E, multi-service vehicles from Techni-Métal Systèmes
and moulds from Herrenknecht Formwork.
In 2012 Herrenknecht opened a branch office for the tender period to support the cli-
ent, the Joint Ventures, consultants and partners involved in the project. In 2013, prior
to the start of the tunnelling works, a subsidiary was founded in Doha (Herrenknecht
Tunnelling Doha LLC, HQA). This subsidiary provided ongoing comprehensive techni-
cal support during all TBM tunnelling phases including planning, assembly, transfer,
tunnelling and dismantling on a 24/7 basis. A warehouse was opened in 2014 for the
Figure 5. Cutting wheel design of Metro Doha EPB
shield
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storage of spare wear parts plus the refurbishment of cutter discs. HQA refurbished
approximately 1,600 cutters for all JV partners during the project. Special equipment
for the TBM transfers was planned and delivered. During the tunnelling period up to 100
Herrenknecht specialists including project managers and project engineers worked on
all TBMs. Several student trainees from universities in Germany also worked for HQA.
The support of all Herrenknecht group brands (TMS, H+E, VMT, MSD) was also orga-
nized and supported through HQA. With such a set-up, Herrenknecht worked very
closely with all contractors, partners and the client.
The scope of delivery of the comprehensive additional equipment comprised the sup-
ply of 31 multi-service vehicles (MSVs) from Techni-Métal Systèmes of which 16 MSVs
were supplied for the Green Line and 15 MSVs to operate on the contract of Gold Line.
In addition to the MSVs the supply contract included a permanent field service techni-
cian and a consignment stock of spare parts to cover both projects.
The six TBMs of the Green Line used navigation and information technology from
VTM GmbH. The navigation system is used to determine and calculate all necessary
data and information for navigating the TBM along the tunnel alignment. The informa-
tion technology comprises the integrated risk and information system for the tunnel,
geomonitoring and deformation monitoring. The machines on the Red Line North and
the Gold Line also used the navigation technology of VMT GmbH.
Herrenknecht Formwork was able to deliver a total of 474 high-quality and high-precision
segment moulds for the Metro Doha Phase 1 in Qatar. For the Red Line North 126
moulds for stationary production were delivered. The contract for the Green line com-
prised 180 moulds for stationary production and handling equipment and the contract
for the Gold Line included 168 moulds for stationary production with handling equip-
ment and ring design. Thus Herrenknecht Formwork could contribute with its deliv-
ery of moulds and segment handling equipment to the production of approximately
350,000 segments for the three contracts Green Line, Gold Line and Red Line North.
H+E was able to support the Gold Line and Green Line with tunnel conveyors, stock-
pile conveyors and cross or transfer con-
veyors. For the Green Line they used a
total 37,400m of tunnel conveyors, 250m
(100m and 150m) of stockpile conveyors
and 103m (47m and 56m) cross or trans-
fer conveyors.
For the contract Red Line South muck
cars were used for muck transport from
the tunnels and the Joint Venture of Red
Line North used their conveying equip-
ment from their earlier project STEP in
Abu Dhabi.
Demand on TBM Production and Logistics for the Machine Manufacturer
For the large-scale construction project of Metro Doha three new metro lines were
built comprising twin tube tunnels of 55km in length. The overall project was divided
into four civil engineering lots to optimize construction operations and to safeguard the
completion of the overall construction program. A critical aspect in such large-scale
construction projects is the purchasing and delivery of the necessary equipment. To
realize the project in time a total of 21 TBMs were needed to fulfil the expectations.
Figure 6. Additional equipment such as conveyor
belts, e.g., for Doha Green Line (picture at Al
Messila Station)
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All TBMs were required to be delivered in a time range between February 2014 and
March 2015 that led to the question if the available machine manufacturers had
the capacity and the possibility to deliver the machines in the given period of time.
Herrenknecht was able to do so and could also guarantee to manufacture and deliver
all 21 machines including back up system and associated equipment within the set
time. The delivery period for all machines for the four metro contracts comprised less
than one year. Seventeen out of 21 machines were manufactured, assembled and
factory tested at the Herrenknecht factory in Germany. The four machines for the
Red Line North contract were manufactured, assembled and factory tested in the
Herrenknecht factory in China. All machines were delivered on site on time.
1. Apart from being able to produce and deliver such a great number of TBMs,
an effective and efficient logistics is also one of the key success factors for
such large-scale construction projects and is also relevant during the con-
struction phase. The logistics have to ensure that all components will be
in the right quantity and at the right time at the point of demand. In order to
avoid delays to the project, the logistics need to be planned very carefully,
in advance and monitored on a daily basis to ensure high reliability of all
construction activities.
Complex regulations made the import of 21 TBMs to Qatar an enormous task for the
machine manufacturer. Coordinating the timing of thousands of parts weighing up to
64 tons each called for high expertise in transport logistics. Delivery to job sites with
pinpoint accuracy in the designated assembly time slot requires exact planning and
coordination with the Joint Ventures on site. In the peak phase of assembly, a loaded
ship carrying TBM components left Antwerp for Qatar every two weeks.
TBM AVAILABILITY AND PERFORMANCE
The tunnelling sections of the Green Line, Red Line South and North and Gold Line
comprised tunnelling sections of between 624 meters and 3,694 meters. The logistics
of the diverse tunnelling drives was handled with mucking out via conveyor belts for the
Green Line, Gold Line and Red Line North and with muck cars for the Red Line South.
According to the contract the machine supplier warranted that each machine achieves
a machine availability of 90%. The machine availability is calculated as follows:
%
T
T T 100
Machine Availability
t
t d
=
#
−
^ h
with Tt as the available working time in minutes and Td the downtime in minutes
due to TBM breakdown or repair which are solely due to a default by the supplier.
Maintenance of the TBM forms part of the available working time in minutes.
The TBM availability for all construction lots was 97% overall and for the Green and
Golden Line mainly in the range of 99% and thus far above the warranty (Figure 7).
Figure 7 shows the TBM availability along the single tunnelling sections with a more
specific subdivision into the main activities illustrated with Figure 8 such as advance,
ring build, pipe extension, logistics and delays from the manufacturer as well as delays
from the JVs.
CONCLUSION
The Metro Doha project is one of the current mega projects with the aim of building a
new and large-scale inner city infrastructure system underground within the given time
frame and with maximum safety. Herrenknecht accomplished extraordinary tasks as
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a machine manufacturer for the Metro Doha by delivering state of the art technology
with 21 TBMs and tailored solutions for this large-scale project reliably and on time.
The demand for the contracted companies was to realize high performance tunnel
construction with minimum impact to the population and the environment. This was
achieved with mechanized tunnelling technology that has established itself in recent
years as pioneering technology emphasized by planning security and handing over
the completed construction on time. Nevertheless, such mega projects can only be
successfully implemented if all parties involved in the construction activities including
the owner, designers, consultants, contractors and suppliers work hand-in-hand. This
is equivalent to the statement made by Dr. Markus Demmler, Senior Director Qatar
Integrated Railway Project: “Managing 21 TBMs working smoothly beneath a metrop-
olis like Doha is only possible with 100% commitment from all partners involved.”
Figure 7. Overview of TBM availabilities for the overall tunnelling sections of each machine and each JV
Figure 8. Overview of TBM availabilities subdivided in main activities including delays
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14
Innovations and Efficiency in Urban Tunnelling—A Case Study
of the Eglinton Crosstown LRT in Toronto, Ontario
Dan Ifrim  Hatch
Andre Solecki  Hatch
Iqbal Hassan  Metrolinx
Paul Cott  Smith Long
ABSTRACT
The Eglinton Crosstown LRT project with 10km of twin tunnels 6.5m DIA in EPB condi-
tions is the largest infrastructure project initiated in Canadian history and is a perfect
example of challenging working conditions in urban tunnelling. Working space con-
straints, hauling of muck, water discharge, noise and vibration limits along with “just
in time” delivery of segmental lining and other materials posed a real challenge to the
tunnel construction logistics.
This paper discusses the project challenges and the design and contractor’s innova-
tive solutions with focus on tunnel logistics, project specific conditions restrictions
and, the impact on TBM productivity and efficiency.
INTRODUCTION
From a social perspective, a bored tunnel for subway, road, utility or railway through
urban areas is generally the preferred option. Many projects around the world enforce
this statement.
Challenges in Urban Tunnelling
Challenges in urban tunnelling are related to environmental protection, real estate,
logistics as well as political and financial implications of dealing with them. Dealing
with challenges starts in the conceptual design and continue through the preliminary
and detailed design when solutions are sought before tendering the project. Not all
problems find the best answer in design; during construction the Contractor may find
alternate resolutions to challenges and cost savings through innovative solutions.
Some of the challenges may find answers in alternate procurement such as design-
built or P3 or early Contractor involvement or Owner procured equipment or materials.
Urban tunnelling may involve small diameter, tunnelling such as microtunnels, to large
diameter tunnels such as metro size or larger. The intent of this paper is to discuss
the challenges related to metro size tunnels with focus on the Eglinton LRT Project in
Toronto, Ontario, Canada.
Managing challenges starts in the conceptual design and continues through the pre-
liminary and detailed design when solutions are sought before tendering a project.
During construction the Contractor may find alternate resolutions to the solutions
found during design challenges and cost savings through innovative solutions and
means and methods are finalized.
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Innovations and Efficiency in Urban Tunnelling 15
URBAN TUNNELLING CASE STUDY
Project Description
The Eglinton Crosstown Light Rail Transit Project is part of an $8.4 billion (2010$
CAD) investment from the Ontario provincial government to expand transit in Toronto,
Canada. The project is being implemented by Metrolinx, an agency of the Government
of Ontario, to provide 19 kilometers of dedicated LRT service connecting the City of
Toronto from west to east along Eglinton Avenue. The Crosstown will be the first LRT
constructed in Toronto and will link regional and local transit, reduce travel time along
the route by half and provide over a thousand jobs during construction.
Two tunnelling contracts, the West Contract (from Keele to Yonge) and the East
Contract (from Yonge to Brentcliffe) are currently under construction to provide opera-
tional service by the year 2021. The underground portion of the LRT alignment is
10 kilometers in length and will be excavated in six tunnel drives grouped into three
segments of twin tunnels.
Tunnel excavation from the west and east contracts commenced in 2013 and 2015
respectively. Tunnels have been excavated using Earth Pressure Balance (EPB)
Tunnel Boring Machines (TBMs) through a series of glacial tills, interglacial and gla-
cial deposits.
As part of the Eglinton Crosstown project, nine cut-and-cover three mined stations
will be constructed under separate contracts once the tunnel excavation is complete.”
Project Challenges
All urban tunnelling challenges are related to tight working space, narrow right of way
and interference with existing utilities and this project was no different. Challenges
with narrow right of way, surrounding structures and utilities together with solutions to
counter these challenges are analysed below.
Surrounding Infrastructure
Urban tunnelling poses unique challenges for a number of reasons one of them being
that the surrounding infrastructure already exists. The risk of constructing tunnels
adjacent to existing buildings, under existing roads, crossing existing highways, utili-
ties or other tunnels needs to be mitigated and reduced to acceptable levels. In most
of the cases the existing infrastructure needed to be protected and kept in operation
during all phases of the project.
Twin Tunnels on Narrow ROW
Narrow right of way (ROW) challenges were related to protecting existing structures
and ensure no obstructions will impede the tunnelling process. On the Eglinton
Crosstown, the horizontal separation from edge of property line to tunnel is less than
1 meter.
Comprehensive settlement monitoring plan was adopted, to ensure a quick response
to eventual settlements. Over 1400 buildings spanned the tunnelling zone of influence,
all of which needed to be analyzed. Data collection and interpretation of buildings in
the zone of influence and identification of possible obstructions was carried out; exist-
ing soil anchors protruding the proposed tunnel path were identified during design and
the tunnel alignment design was modified to mitigate any potential obstruction impacts
during tunnelling.
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Utilities
Limited records of old existing utilities created additional challenges and gener-
ated unplanned cost and schedule extension. Some level of inaccuracy is always
expected; however inaccuracies at the location of extraction shaft 3 (ES-3) were
beyond expectations.
A number of undocumented utilities were found upon excavation and consequently
shaft temporary support and excavation with typical mechanical equipment needed
to be halted. A number of methods were employed to document existing utilities to
enable shaft temporary support; however that was not possible along the entire shaft
perimeter. The process was complemented by hand excavation and erection of tem-
porary supports on ongoing basis. Casing and supporting of existing utilities and ser-
vices were employed where relocation was not deemed possible.
Use of Jet-Grouted Head Walls
Jet grout blocks were the preferred method of excavation support for station headwalls
since they reduced the number of required utility relocations and can reach deep
installation between existing utilities. Secant piles were used a Keele, Caledonia and
Dufferin stations since station design had already advanced to 30% and the station
designers did not accept jet grout SOE.
Multiple brick sewers were identified along the tunnel alignment and two sections were
identified as sensitive by a CCTV inspection. A slip lining was installed in the sensi-
tive sections of sewer in advance of tunnelling. Jet grouting was adopted in several
locations in lieu of the secant piles to reduce the impact on existing utilities relocation.
Obstructions to Tunnelling
As the Eglinton tunnel alignment is located in a congested and developed area, the
possibility of a man-made obstruction to tunnelling was considered a major risk.
Consequently, the design included a desktop investigation and historical archive
search to identified potential obstructions. Where known obstruction were found,
Figure 1. ES-3 existing subsurface conditions—shaft support planning
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the alignment needed to be re-designed or the obstruction needed to be removed in
advance of tunnelling.
One significant obstruction to tunnelling was support of excavation installed for the
Eglinton West Subway which was cancelled in 1995 after construction had started.
No records of the status of work upon cancellation were available, so a site investi-
gation was required to determine what had been installed. The test pit investigation
confirmed 21 steel piles which impeded the tunnel alignment and it was decided to
remove these prior to tunnelling.
Significant obstructions were present at the Spadina subway line as a result of the box
structure and associated support of excavation. The obstructions contributed to the
division of tunnel drives as discussed in the following section.
Crossing Existing Subway Lines
Challenges specific to Eglinton LRT project are related to the interchange station at
Allen Road and Eglinton Avenue for interchange with University-Spadina Subway Line
and interchange station at Yonge Street and Eglinton Avenue for interchange with
Yonge Subway Line. The construction of the interchange stations includes replace-
ment and relocation of existing utilities in the area.
The process started at the design and planning phase and included the removal and
relaunching of the West tunnel TBMs at Allen Road, construction of the respective
shafts and transportation of the TBMs above ground at Allen Road. The process con-
tinued with the temporary storage of the West tunnels TBMs in ground beneath Yonge
Street and construction of an exit shaft for the removal of the East tunnels TBMs. All
these extreme solutions were part of both Designer and Contractors efforts to mitigate
the specifics constrains at the optimum cost.
Crossing University-Spadina Subway Line
During the design phase for the project the vertical alignment around Allen Road/
Eglinton West Station was identified as a challenge due to the number of constraints
in the vicinity including the University-Spadina Subway box structure and associated
abandoned support of excavation, an 1830mm sewer and a 1980mm sewer installed
beneath Eglinton Avenue. The following bullets describe the rationale for specifying
the extraction, transport and re-launch of the TBMs at Allen Road and over the Toronto
Transit Commission (TTC) existing subway box structure:
Figure 2. Secant piles vs. jet grouting support planning
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ƒ
ƒ Tunnelling beneath the TTC box structure would require pre-support such
as compensation grouting or mud jacking and would need approval from the
TTC.
ƒ
ƒ The tunnel alignment would be required to be lowered further than the current
design to mine beneath the TTC structure in order to any avoid obstruction
with the TTC box structure and abandoned support of excavation. This would
increase the future station excavation depth and consequently increase con-
struction costs.
ƒ
ƒ Since tunnelling is a continuous linear construction process, mining the
entire alignment from Black Creek to Yonge (6.4 km in length) would extend
the construction schedule in order to complete the inverts, walkways, cross
passages and other finishing works. Staging tunnelling in two separate drives
allows turning over the first portion of tunnels between Black Creek to Allen
earlier than staging tunnelling from one location.
ƒ
ƒ The distance from Black Creek to Yonge is approximately 6.4 km. Tunnelling
this distance without any significant refurbishment posed a risk to tunnelling.
Having the TBMs re-surface at Allen Road would allow them to be fully refur-
bished at approximately the mid-point of the tunnel alignment, reducing the
risk of significant machine downtime.
TBM Move
To reduce the schedule impact of extracting and relaunching the TBMs, the contractor
decided to lift and transport the TBMs in one piece instead of disassembling, trans-
porting and reassembling the machines as originally envisioned.
Each TBM, weighted approximately 430 tonnes each, was transferred from ES-1 to
LS-2 above ground over the existing Spadina Subway line. The transfer was done
overnight with minimal road closures in one weekend as discussed in more detail by
Liebno et. al. (2016).
Figure 3. Allen Road and Eglinton Avenue
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The move was orchestrated by the con-
tractor and a specialized heavy lift sub-
contractor Mammoet and consisted of
mobilizing a hydraulic strand jack gan-
try crane and a hydraulic self-propelled
modular trailer. This TBM move was an
innovative solution to the urbanized chal-
lenges and ultimately reduced the TBM
assembly and disassembly schedule and
provided less construction impact to the
public. A schedule for the move was pro-
vided to public (Figure 4).
Crossing Yonge Subway Line
Similarly to crossing the University-Spadina Subway line, it was undesirable to tunnel
through due to complexity of the Yonge subway station; therefore the tunnel drives
were configured to terminate at each side of the Yonge Subway station. As a result,
extraction shafts were required on either side of the intersection of Yonge and Eglinton.
This location was the most comprehensively developed intersection on the alignment.
Given the project procurement structure and timing the final exit shaft of the tunnels
both on the West and the East contract were not ready in time for TBMs retrieval.
On the West Contract the TBMs were advanced within the Yonge station limits and
parked there until the station excavation advances far enough to allow for TBM
removal.
On the East Contract the TBMs were advanced within the Exit Shaft limits and parked
there until shaft excavation advanced far enough to allow for TBMs removal. During
the parked period the TBMs were subject to regular monitoring to ensure the TBM
remained sealed to prevent ground loss.
Figure 4. TBM move schedule
Figure 5. TBM move at Allen Road
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Settlement Monitoring
In urban environments controlling settlement is essential to protect the roadway, utili-
ties and adjacent structures. Monitoring instrumentation was installed along the tunnel
alignment and instruments were monitored at a frequency determined by the TBM’s
proximity. Review and alert levels corresponding to volume losses of 0.5% and 1%
respectively were set. In general, settlement performance far exceeded the predicted
review level. On the west tunnels drive, the average settlement was less than 5mm
and corresponded to and average volume loss of 0.17%. The exceptional control of
ground loss on the Eglinton Crosstown greatly mitigated impacts and damaged to
adjacent structures along the narrow tunnel right-of-way (Solecki et al 2016).
Challenges to Tunnelling Logistics
Small Working Area Footprint
Launch and extraction shafts locations and footprint were restricted by available land.
Launch Shaft 1 (LS-1) was located on a public park and within two lanes of Eglinton
Ave. Road traffic continued to use two lanes beside the shaft. Extraction Shaft 1 (ES-1)
Table 1. Working site area
Area (m2) Launch Shaft 1 Launch Shaft 2 Launch Shaft 3
Site 12,000 7,600 17,353
Shaft 1,200 1,780 2,057
Surface (incl. decking) 10,800 7,2001 17,353
Office 270 2404 300
ubstation 300 260 542
Grout Plant 330 175 450
Water Treatment 60 60 60
Muck Pit (Surface) Excavator Work Space 600+400 360+2002 467
Muck Pit (Shaft) NA 167 NA
Contaminated Soil Pit Excavator Work Space 160+100 185+2002 410
Crane Pad 1×190 2×190 1×190
Segment Storage 1,200 700 2,150
Segment Heating 200 140 408
General Storage 1,500 800 216
Mechanical Shop 300 300 218
% Open Space3 50% 44% 45%
Offsite Storage — 14,000 —
Offsite Owner Offices 450 450 600
Offsite Owner Parking — 1,000 1,000
Table 2. Tunnelling duration and production data
Tunnel Drive Drive 1 Drive 2 Drive 3 Drive 4 Drive 5 Drive 6
Tunnel Length (m) 3546.7 3546.5 2864.3 2863.3 3281 3262
Duration (days) 347 303 204 210 309 281
Tunnelling duration (days) 221 208 172 172 161 156
Average production over duration (m/day) 10.2 11.7 14.0 13.6 10.6 11.6
Average production while mining (m/day) 16.05 17.05 16.65 16.65 20.38 20.92
Best day production (m) 33 35 33 32 40 47.5
Best Week (m) 128 138 128 125 148 158
Best Month (m) 426 411 486 408 553 485
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was constructed under Eglinton Ave from a public parking lot. Decking was installed
over half of the shaft for road traffic to continue one lane in each direction.
Launch Shaft 2 was the most restricted launch site. LS-2 was initially a public parking
lot and required realigning an expressway ramp to provide working space. LS-2 was
similarly located entirely under Eglinton Ave with decking over half the shaft providing
two lanes of traffic and decking on the other half of the shaft within the site providing
780m2 of additional area for storage and equipment.
Launch Shaft 3 was the largest launch site and was constructed under two lanes of
Eglinton Ave and a large hillside boulevard. The extraction shafts for the Drives 3
and 4 (ES-2) and Drives 5 and 6 (ES-3) were located at the most heavily developed
area on the alignment at Yonge Street and Eglinton Ave. ES-2 was planned to be
constructed at the location of a former bus terminal and ES-2 was constructed under
the Eglinton roadway.
Launch shaft #2 (LS-2) was more restrictive in size than LS-1 and LS-3 due to location,
conditions and required TBM launching in a umbilical configuration. An initial mining
phase included completion of the TBM assembly and installation of the tunnel con-
tinuous conveyor. From Table 2 we could understand the complexity of the launching
process at each drive correlation the duration required for TBM assembly, and initial
mining with the total duration.
Efficiency of launching was clearly affected by the location constraints; however daily
productions were within the same range.
Innovations were required particularly at LS-2 for logistics due to the constrained
working space. Innovations included installing decking over the shaft within the site
as previously discussed. The Contractors employed two trains for each drive oper-
ated from the launch shaft and used a ‘California Switch’ to allow passing prior to
entry into the tunnel. At LS-2, two lift windows were left in the decking to provide the
crane access to the materials trains for each tunnel. And a third opening was used by
the muck removal crane. The decking accommodated the ventilation equipment and
segment storage as well. The contractor also used stacked construction trailers to fit
within the reduced footprint of construction site.
Decking as Solution to Traffic Management
Eglinton Ave is an arterial road in Toronto so maintaining two-way traffic flow at all
times was a requirement of the tunnelling contracts. Since the launch and extrac-
tion shafts and emergency exit buildings were constructed partially or wholly under
Eglinton Avenue, the Designer and Contractors developed and implemented rigorous
plans for traffic control and management in relation with the work schedule at these
locations. At LS-1 and LS-3 open lanes of traffic were maintained around the shaft. At
ES-1, LS-2 and ES-3 road decking was required to provide lanes for two-way traffic.
Staging plans were developed and implemented maintain two-way traffic work was
performed. Street closures were only adopted for limited times and only at off peak
times (weekend nights).
Multiple Handling of Materials
As a result of constrained site space, particularly at LS-2, just-in-time delivery of mate-
rials and off-site storage yards and warehouses were required to maintain a flexible
supply of materials.
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Ahead of starting tunneling, the following
logistics measures were implemented:
ƒ
ƒ A trucks staging area was
made on the incoming route
of the mucking and tunnel
precast trucks. With the City
of Toronto approval, the con-
tractor built a two way stag-
ing zone on the trucks route in
nearby proximity to site, within
radio communication with the
site.
ƒ
ƒ A temporary storage yard was
set up, again, on the tunnel precast truck route and within 4 km from the site,
to act as an overflow/buffer mean for the tunnel precast delivery and other
materials (rail, tunnel conveyor frames, tunnel conveyor belts, etc.)
ƒ
ƒ Muck removal from site with the trucks was timely segregated from tunnel
precast delivery-the muck removal trucking started 5 am finishing 4:00 pm
(80 to 140 trucks/day), and the tunnel precast receiving started 4:00 pm fin-
ishing 9:00 pm (15–20 trucks/day).
ƒ
ƒ All warehousing configuration on site was built on two levels, to reduce the
surface footprint and allow more site storage and vehicles maneuvering.
ƒ
ƒ A section of the open area of the shaft was decked within the site, engineered
to withstand the storage of additional 30 precast tunnel rings.
Continuous Conveyors
The muck resulted by the tunnel excavation need to be removed out of the tunnels.
Both tunnel contractors for the West and East contracts installed innovative setups to
remove the muck by continuous conveyors. The continuous conveyors were delivering
the muck from the TBM straight to surface located muck pits at two of the three work-
ing sites (Keele/Eglinton and Leslie/Eglinton).
At Launch Shaft 2 there was insufficient space for a conveyor to transport material up
to the surface muck pit so the Contractor adopted a hybrid solution by installing a two
chamber muck pit in the shaft from where the muck was extracted by a crane with a
clam to accommodate for the small foot print.

Figure 6. Decking of working shaft at LS-2
Figure 7. Continuous conveyor at LS-3
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The continuous conveyors were designed and manufactured by the specifics of each
working sites. The benefits of the continuous conveyors were becoming visible with
the length of the tunnel drives; the trains were strictly utilized to transport the materi-
als and consumables for the TBM and tunnel advance including the segmental lining.
These include greater TBM advance availability, less down time and simplified logis-
tics when compared to rail-based muck removal by rail cars.
Muck Handling and Treatment
Although the TBMs were using only bio-degradable additives at times the muck was
more fluid than required for immediate transportation.
In other instances while mining through jet-grouted walls the muck did not meet the
criteria for disposal at regular disposal sites and required transportation by cisterns at
treatment locations and disposal at special approved disposal sites.
The contractors adopted ingenious logistics and at times incurred additional cost to
maintain the planned schedule.
As the removal of the muck from the shaft was done by clamming, the shaft muck
pit was staged, creating an isolated discharge for each tunnel. That allowed not only
segregation of soils between the tunnels, but also ensure productive mining for one
TBM while the other one was mining through the jet grout walls. Also on the surface a
secondary “contaminated” muck pit was built, as the high PH soil of the jet grout walls
was stored in this isolated pit for trucking. Muck removal was staged (talk about shaft
muck pit and double handling).
Interventions at Secant Pile and Jet Grout Headwalls
Secant pile and jet grout headwalls were used to perform interventions to avoid work
in hyperbaric conditions. Yamashita et al. (2015) presented the contractors innovative
processes developed to control flowing ground during interventions.
At secant pile headwalls, the TBM was advanced so the head was in full contact with
the wall. External dewatering was used to lower the ground water and chemical grout
was used to seal the TBM to the treated ground to prevent flowing water and soil
towards the depressurized head.
In the jet grout headwalls the cutterhead was advanced to the midpoint of the wall and
chemical grout was used to seal around the machine. The jet grout permitted interven-
tions to be completed without dewatering the soil.

Figure 8. In shaft muck pit (LS-2) vs. portal muck pit (LS-3)
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CONCLUSIONS
Urban tunnelling is different and most of times is a difficult and risky endeavour.
Money invested in heavy construction impacts upon other community interests and
services and the politics are more complex than in rural areas. Urban tunnelling proj-
ects demand a client with the ability to select and combine competent specialised
engineers to get the best quality product for the taxpayer.
Experienced Engineers, Consultants and Contractors, employing state of the art
TBMs, systems and technologies, performing a comprehensive risk mitigation and
management together with an innovative approach to tackle specific challenges can
result in a very successful project such as the Eglinton Crosstown LRT.
REFERENCES
Liebno, D., Yamashita, J., Nishikokura, O., and Sheehan, M. “Mechanized Tunnelling
Driving Toronto’s Big Move Eglinton Scarborough Crosstown Tunnel Construction
(ECLC1-15),” WTC 2016, San Francisco, USA.
Noah Johnson, The Robbins Company, Urban EPB Tunneling in Limited Space: A
Case Study of the San Francisco Central Subway Project
Solecki, A., Taghavi, A., and Hassan, I. “Redefining Settlement Control Industry
Standards with Modern Mechanized EPB Tunnelling: Eglinton Crosstown LRT Case
Study,” WTC 2016, San Francisco, USA.
Yamashita, J., Nishikokura, O., Sheehan, M., and Stewart, C., TBM Cuttinghead
Interventions at Eglinton-Scarborough Crosstown Tunnel Construction (ECLC1-15),
RETC 2015, SME, New Orleans, USA, 962–970.
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25
Wear of Cutting Tools on an EPB TBM Tunneling Through
Glacial Soils
Lisa Mori  Jay Dee Contractors, Inc.
Ehsan Alavi  Jay Dee Contractors, Inc.
Brian Hagan  Jay Dee Contractors, Inc.
Michael A. DiPonio  Jay Dee Contractors, Inc.
ABSTRACT
Prediction of tool life and wear for soft ground pressurized TBMs is a challenging
task for contractors, machine manufactures, and designers. The issue of cutterhead
inspection and maintenance in Earth Pressure Balance (EPB) tunneling can be a dan-
gerous, time consuming, and costly process, particularly when the ground is unstable.
In this case, cutterhead inspection and tool maintenance are performed under pres-
surized conditions or “hyperbaric interventions.” Severe primary and secondary wear
on the cutters has been seen in some of the projects in glacial soils including Seattle
area. This paper discusses the experience gained regarding cutting tool wear from an
EPB TBM that mined through 8.85 km of glacial soils in Seattle, WA over the course
of two separate tunneling projects.
INTRODUCTION
During the last 15 years, several tunneling projects in Seattle including the Brightwater
tunnels, Beacon Hill tunnels, Mercer Street Tunnel, Henderson Way Tunnel and Sound
Transit’s University Link and Northgate Link tunnels were excavated by using pressur-
ized shielded machines.
Despite the fast growth in the use of soft ground Pressurized TBMs in the tunnel-
ing industry, prediction of tool wear prior to excavation and monitoring and mainte-
nance of tools during the excavation is a challenging task for contractors, machine
manufactures and designers. The issue of cutterhead inspection and maintenance in
Earth Pressure Balance (EPB) and Slurry TBMs can be a dangerous, time consum-
ing, and costly process particularly when the ground is unstable. In this case, cutter-
head inspection and tool maintenance are performed under pressurized conditions
or ‘‘hyperbaric interventions.” Severe primary and secondary wear on the cutters has
been seen in some of the projects in glacial soils. As an example, mining on the two
central tunnels of the Brightwater Project (BT2 and BT3) was halted in May 2009 due
to severe wear damage to the cutterhead on both machines (Tunneling Journal 2011).
Although the BT2 machine was repaired and finished its run, the BT3 machine was
stranded.
This paper will discuss in detail the severe primary and secondary wear on the cut-
ters of an EPB TBM that tunneled through 8.85 km over the course of two projects in
Seattle, WA. In addition, some of the experience and remedies that were utilized to
address the cutterhead wear and improve the life of the cutters along these two proj-
ects are discussed. In the next section an overview of these projects as well as their
subsurface geotechnical properties are presented.
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University Link Light Rail (U230) Tunnel Project
The University Link Project consists of approximately 5.1 km of twin Light Rail Transit
tunnel commencing from the north end of the Pine Street Stub Tunnel in down-
town Seattle to the University of Washington Station near Husky Stadium. Jay Dee
Contractors, Inc., Frank Coluccio Construction Company, and Michels Corporation
have formed a Joint Venture (JCM U-LINK, JV) to construct the portion of the tunnels
from Capitol Hill Station (CHS) to the Pine Street Stub Tunnel (PSST) which is called
Contract U‑230. This contract includes the construction of twin tunnels which are each
1.2 km in length.
Geologic description of this project can be divided to fluvial deposits, glacial deposits
and lacustrine and glaciolacustrine deposits, all of which have been glacially over-
ridden. Figure 1 shows the geological profile of the project.
N125 Northgate Link Light Rail Extension Project
The Northgate Link Extension will extend service north from the University of
Washington to the University District, Roosevelt, and Northgate neighborhoods by
2021, and is expected to cost approximately $2.1 Billion. Most of this 6.9 km exten-
sion will be underground, and the N125 contract includes the construction of 5.6 km
of twin EPB tunnels. Also included are the excavations of the Maple Leaf Portal (MLP)
where the light rail will transition from tunnels to elevated guide-way and two large
underground station boxes, one for the University District Station (UDS) and one for
the Roosevelt Station (RVS).
The geology of the N125 project is very similar to that of University Link in that the tun-
nels are constructed through glacially overridden fluvial and lacustrine deposits. The
two major differences are that N125 will encounter a large amount of glacial till and
till-like deposits and that N125 will encounter much more coarse-grained soils overall
than University Link. Figure 2 shows the geological profile of the project.
Figure 1. U230 University Link Light Rail Extension geological profile
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Wear of Cutting Tools on an EPB TBM Tunneling Through Glacial Soils 27
U230 and N125 Tunnel Boring Machines
A new HitZ TBM was fabricated by
Hitachi Zosen for use by JCM on the
Sound Transit U230 project. The TBM
fabrication was completed in 2011. The
Sound Transit U230 Project consisted of
twin-bored (northbound and southbound)
tunnels each with an approximate length
of 1200 meters from Capitol Hill Station
to Pine Street Stub Tunnel in Downtown
Seattle. The tunnels had an outside
diameter of 6.27 m and an inside diam-
eter of 5.74 m. The HitZ TBM completed
both tunnels, starting in 2011 and finish-
ing in 2012 (Figure 3).
JCM decided to refurbish this TBM and use it for the excavation of one of the twin tun-
nels in N125 project (see Figure 4 and Table 1).
CUTTING TOOL WEAR MEASUREMENT METHODS
Scrapers, precutters, and disc cutters were utilized in different sections along the
alignment of these two projects. A unique identification and measuring system was
developed to monitor the cutter wear. The scrapers were numbered from the center to
the periphery of the cutterhead, for each of the two sides of the spoke, left and right
(see Figure 5). E.g., scraper 53R is the third scraper on the right side of spoke 5. The
wear of scrapers was defined by the remaining length of the scraper protruding from
Figure 2. Northgate Link Light Rail Extension geological profile
Figure 3. Original machine in factory
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the spoke subtracted from the original length (see Figure 6a). The measurement was
taken at three points along the scraper, in the middle and on each side (see Figure 6b).
The same unique system of numbering was developed for precutters (see Figure 5).
The wear of pre-cutters was defined by the remaining length of the carbides sub-
tracted from their original length (see Figure 6c).
Two different types of precutters were used on the U230 project: low precutters and
high precutters. The main difference between the low and high precutters was their
welded position. Low precutters had a height of 110 mm and were welded into the cut-
terhead spoke while high precutters had the same initial height but were welded into the
interchangeable boxes (overall height from the spoke was 130 mm for high precutters).
Based on the experience gained through the U230 project, it was decided to use the
same height for all the precutters. The overall height of the precutters was increased
from 130 mm (from the spoke) in U230 to 170 mm (from the spoke) in N125 project.
Figure 4. Side view of the refurbished Northgate Link TBM design
Table 1. Specifications for the Refurbished North Link HitZ TBM
Hitachi Zosen
Excavation Diameter With Soft Ground Tools 6,640 mm
Cutterhead Type Bidirectional, mixed ground
Opening ratio 45%
Cutterhead drive Electric motors with VFD
Cutterhead power 720 kW (8×90 kW)
Cutterhead speed 0~2.2 rpm
Torque Cutterhead working torque 2970 kN-m
Thrust Trust jack stroke 2,300 mm
Maximum thrust 40,000 kN
Electrical Primary voltage 13,800V
Protection Class 1, Div 2
Conveyors Screw conveyor diameter 800 mm Shafted
Screw conveyor type Two stage, periphery drives, end discharge, and
shaft style auger with replaceable wear protection
on flights and casing
Speed 1.0~18.3 rpm
Torque 80 kNm
Back-up conveyor belt width 750 mm
Weights TBM weight (approx.) 320 tonnes
Back-up weight (approx.) 200 tonnes
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Wear of Cutting Tools on an EPB TBM Tunneling Through Glacial Soils 29
Figure 5. Numbering of scrapers, precutters, gauge cutters, and overcutters on the cutterhead

Figure 6. Side view of scraper with 100 mm protruding from spoke (a). Wear measurement locations for
precutters (b) and scrapers (c) depicted with red arrows.
(a)
(b) (c)
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