Tunnel Updates

Three times per year, TBM: Tunnel Business Magazine recaps the status of major tunneling projects underway in the United States and Canada. Below is the Tunnel Update that appeared in the February 2022 issue of the print edition.

Joint Water Pollution Control Plant Effluent Outfall Tunnel Dragados USA

The Los Angeles County Sanitation Districts (Sanitation Districts) are undertaking the $630.5 million Joint Water Pollution Control Plant Effluent Outfall Tunnel project (Project). The project involves constructing a tunnel approximately 7 miles long and 21.5 ft in excavated diameter (18 ft in internal diameter) to convey disinfected, secondary-treated effluent from the Sanitation Districts’ Joint Water Pollution Control Plant (JWPCP) located in the City of Carson, California, to an existing ocean discharge system at Royal Palms Beach in San Pedro in the City of Los Angeles. The tunnel is being constructed beginning at the JWPCP Shaft Site (entry shaft) and ending at Royal Palms Beach (exit shaft). The alignment will vary in depth from approximately 50-ft to 450-ft below the ground surface. The entire tunnel alignment will be below the groundwater table with pressures ranging from 1 to 9 bar. As part of the scope, a 14-ft diameter cast-in-place concrete connection will be constructed to convey the treated effluent from an existing force main to the JWPCP Shaft. Other notable Project features include an approximately 60-ft diameter and 113-ft deep drop shaft, a junction structure and two valve structures at the JWPCP and a manifold structure at Royal Palms Beach.

Tunneling will go through two very distinct ground conditions. The first half of the tunnel will be through soft ground with depths up to 110 ft. The second half of the tunnel will be through hard rock with depths up to 450 ft where the tunnel will be subjected to intense ground squeezing conditions due to the overburden pressure.

Work at the JWPCP Shaft Site started in the summer of 2019. Construction of the access shaft slurry wall excavation support system was completed in December 2019. Excavation of the shaft in dry and wet conditions, which was followed by shaft tremie slab construction and dewatering, was completed August 2020. Open cut construction of the 14-ft diameter cast-in-place concrete Connection A from the proposed Junction Structure No. 1 to the JWPCP Shaft was substantially completed in October 2020. Jet grouting activities for the tail tunnel, starter tunnel, and three safe havens were completed in May 2021. Excavation of the starter and tail tunnels was completed in May 2021. The Contractor is using a Herrenknecht slurry TBM, which arrived onsite in late 2020. The TBM has been named "Rachel" in honor of Rachel Carson, who authored the book Silent Spring that was credited with sparking the global environmental movement. Fabrication of test precast concrete segments at the Traylor Bros. Inc. Littlerock, California, facility began in April 2021. Tunnel mining began in September 2021 and is anticipated to be completed by mid-2024. The first hyperbaric intervention for TBM cutterhead inspection and maintenance was successfully completed in January 2022.

Lead Design Consultant: Parsons; Tunnel Design Consultant: McMillan Jacobs Associates; Tunnel Construction Management Consultant: Mott MacDonald; Listed Major Subcontractors for Dragados – Excavation and Structures: W.A. Rasic Construction Company, Inc.; Jet Grouting and Support of Excavation: Malcolm Drilling Company, Inc.

Project Personnel: Los Angeles County Sanitation Districts – Construction Management Section: Ignacio Murillo, Section Head; Russell Vakharia, Resident Engineer/Construction Manager; Sewer Design Section: Anthony Howard, Section Head; Oscar Morales, Supervising Engineer; Yoonkee Min, Senior Engineer. Parsons – Danson Kelii, Project Manager. McMillan Jacobs Associates – John Stolz, Lead Tunnel Design Consultant. Mott MacDonald – Daniel McMaster, Lead Tunnel Construction Management Consultant. BabEng – Allen Jensson, Lead Tunnel Engineer. Dragados – John Kennedy, Vice President of Southern California Operations; Claudio Cimiotti, Project Manager; John Truong, Deputy Project Manager; Nicholas Karlin, Project Engineer.

Silicon Valley Clean Water Gravity Pipeline Project Barnard Bessac Joint Venture (BBJV)

This $206.7 million project for Silicon Valley Clean Water (SVCW) includes 17,500 lf of tunnel with two independent tunnel drives and 4 shafts (2 Retrieval Shafts, 2 Tie-In Shafts). The tunnel diameter is 16.2-ft OD with depths ranging from 30-ft to 60-ft below ground. The geology comprises medium to stiff clay with layers of sand and silty sand geology. Crews are using EPB tunneling methods with a second pass liner inside the tunnel consisting of 10-ft and 11-ft fiberglass reinforced polymer (FRP) pipe. Construction NTP was issued in November 2018, with an estimated substantial completion date of July 2022.

The project is 90% complete. BBJV continues to achieve new milestones including: completion of the 10-ft-dia. FRP pipe install in Tunnel Drive 1; completion of the 6-ft-dia FRP pipe within the San Carlos Adit; completion of annular cellular grouting of the FRP pipe in the downstream half of Tunnel Drive 2; and after dealing with the global shipping sagas that many of us our becoming all too familiar with these days, completion of the final deliveries of the 10-ft-dia. x 24-ft-long FRP "tee" for the Bair Island drop structure which is a critical tie-in component. Remaining work includes installation of FRP pipe in the upstream half of Tunnel Drive 2 which was scheduled to be complete during the first week of February 2022 and is the last remaining section of FRP pipe to be installed in the tunnel. BBJV's subcontractor Pacific International Grout Co. (PIGCo) is approximately 50% complete with installation of low-density cellular concrete (LDCC) on the project. The cellular concrete is injected on 100-ft intervals into the annulus between the extrados of the FRP pipe and the intrados of the precast concrete segmental tunnel liner in both Tunnel Drives.

In addition, crews installed the remaining San Carlos branch of the FRP pipeline within the adit. This section of FRP pipe consisted of a 25-ft-long section and connects the main pipeline to the San Carlos drop structure. BBJV crews lowered five pieces of FRP pipe (6 ft-dia. x 5-ft long) one by one down the 50-ft-deep San Carlos Shaft. The San Carlos adit pipe sections were coupled together inside of a steel casing pipe, which had previously been pipe-jacked into place and served as the adit SOE.

A unique challenge associated with this project was ensuring the FRP pipe did not float during cellular concrete operations. Securing the 10 ft-dia and 11-ft-dia FRP pipe within the tunnel to ensure was identified as a project risk, which received a significant amount of detail during design. As such, BBJV designed and installed a screw jack system that secured each piece of FRP pipe in six individual locations per piece of pipe. The screw jack system allowed for continuous tension to be applied against the pipe, and ultimately resisted the buoyancy forces realized during the cellular concrete operation.

Additionally, unique fiberglass laminations were required at the two critical tie-in locations where pre-fabricated sections of the FRP pipe, specifically a WYE connection and a TEE connection, met the inlet structure piping and drop structures, also made of FRP material. The WYE connection has been completed to date and the TEE connection lamination is scheduled for Q2 2022.

Engineer: Arup; Construction Manager: Tanner Pacific; Major Subcontractors: Drill Tech Drilling and Shoring; Blue Iron Shoring; Malcolm Drilling; PIGCO; TBM Manufacturer: Herrenknecht; Precast segment supplier: Traylor Shea Precast; FRP Supplier: Future Pipe Industries; FRP logistics company: Infrastructure Solutions LLC.; Specialty Equipment Manufacture: Kelley Engineered Equipment, LLC.

Project Personnel: Project Manager: Jack Sucilsky; General Superintendent: Mike Hanley; Assistant Project Manager: Allison Strid; Field Superintendents: Ben Weldin and Matt Jackson.

Mountain Tunnel Improvements Project Michels Tunneling

The $139 million project for the San Francisco Public Utilities Commission (SFPUC) is in the central Sierra Mountain Range near the town of Groveland in Tuolumne County. The existing tunnel begins at Early Intake Reservoir on the Tuolumne River and extends approximately 19 miles west to the Priest Reservoir, near the town of Groveland.

The scope of the work includes: existing tunnel interior repair and modification work within the 19 mile tunnel length which includes; concrete lining repairs, contact grouting, pressure grouting, approximately 5,000 lf of new concrete invert paving, demolition of existing bulkheads and installation of new bulkheads, bulkhead improvements and debris removal. Construction of new tunnel improvements which includes a new Flow Control Facility (FCF) which is comprised of a 55 ft diameter, 150-ft deep new shaft, bypass tunnels and connections with the existing tunnel; the construction of new portal, 1,000 ft long adit, tie-in of the adit to the existing tunnel, construction of a new access shaft with a new connecting adit, new siphon extension of about 300 ft with an inclined shaft connecting to the existing tunnel and installation of approximately 1,500 ft of steel pipe lining.

The 150-ft deep and 55-ft internal diameter FCF shaft will be constructed primarily in a schist formation. The FCF bypass tunnels, which are horseshoe shape with varying dimensions, will also be constructed in schist. The 1,000-ft long horseshoe shape adit will constructed in both diorite and schist. The 100-ft deep and 17-ft internal diameter access shaft and bypass tunnel siphon extensions will be constructed in diorite. It is expected that drill and blast will be the construction method for all underground construction.

The project is approximately 15% complete. FCF shaft excavation has progressed to about 50 ft. The adit portal has almost been completed with construction of 50-ft high walls. The 1,000-ft long adit excavation is expected to begin in the first quarter of 2022. Other adit access roads and slope stabilizations are progressing at a good rate. The first 60-day Mountain Tunnel shutdown began in January and the first round of work commenced inside the tunnel while continuing construction on the outside of the tunnel. Final completion is expected by December 2026.

Lead Design Consultant is McMillen Jacobs Associates, SFPUC Construction Management Bureau is the construction manager, construction management and construction inspection provided by AECOM; Major coordination with Hetch Hetchy Water and Power, Ted Allen; Major Michels subcontractors include Apex Rockfall Mitigation, Kroner Environmental, Schrader Mechanical, Cody Builders Supply, Renesco Inc. and Mach8Bio

Personnel: SFPUC – Regional Project Manager: Randy Anderson; Project Engineer: Joseph Buitrago; Regional Construction Manager: Jerry Malone; Resident Engineer: Fredrick "Paco" Larsen; Public Outreach: Betsy Lauppe Rhodes; McMillen Jacobs and Associates – Project Manager: Jennifer Sketchley, Associate; Design Project Manager: Renee Fippin, Principal: Tunnel Engineer: Glenn Boyce, Principal; AECOM – Contract Manager: Steven Tidwell, Vice President; Lead Inspectors: Thomas (Bud) Degrio, Kevin Bolle, Mark Leonard, James Brown and Jon Wolfe; Safety Manager: Rick Cavil; Michels Tunneling – Project Manager: Ed Whitman; Project Engineer: David McCallum; Project Superintendent, Ron Klinghagen.

North East Boundary Tunnel (NEBT) Salini Impregilo Healy JV (SIH JV)

The $579.9 million Design & Build project for DC Water involves the design and construction of Division J of the DC Clean Rivers Project called North East Boundary Tunnel (NEBT). The project includes the construction of 26,700 ft of tunnel with 23 ft inner diameter from 60 to 140 ft below grade. The tunnel is excavated using an Herrenknecht EPB TBM (Earth Pressure Balance Tunnel Boring Machine). The first section of the NEBT is excavated in a clay soil and the second part of the tunnel is in a sandy layer. Mix face conditions were expected for most of the tunnel alignment. The project also includes the construction of 7 shafts, ranging from 20 feet to 55 ft diameter, and supported by unreinforced slurry walls or secant piles and lined using Cast in Place concrete. There are also 6 adits to be excavated using the Sequential Excavation Method (SEM) in ground previously improved through either jet grouting or ground freezing techniques. Finally, a 700 ft length of Diversion Sewer with 10 ft of internal finished diameter will be constructed using an EPB (Earth Pressure Balance) TBM (Tunnel Boring Machine) in clay soil which it will be lined with HOBAS pipes installed using the pipe jacking tunneling method.

As of December 2021, 80% of the works were completed. The tunnel excavation was completed in April 2021, the TBM disassembly in June 2021. The tunnel cleanup operations have been completed and the tunnel segment final reparation works are ongoing. The excavation of all the seven drop shaft is already completed as well as the final concrete Cast In Place (CIP) liner. The construction of the hydraulic structures inside the shaft are ongoing in almost half of the project drop shafts. 66% of the Adit construction works have been completed while most of the final connections between adits and NEBT tunnel still need to be performed. The ground freezing system implemented for the excavation of one adit of the project is currently ongoing and the excavation activities will start as soon as the temperatures reach the designed values. Regarding the diversion facilities to be constructed on the surface (Near Surface Structures), the support of excavation system and the ground improvement have been fully completed while the excavation and the permanent structures construction are ongoing in most of the construction sites. The 10-ft diameter TBM arrived on site last June 2021 and started the excavation of the 700-ft Diversion Sewer in August 2021. The drive was completed at the end of October 2021 and a total of thirty-eight (38) HOBAS pipes 20’ long have been used to construct this tunnel. Final completion is expected by March 30, 2023.

Unique aspects of the project include: Ground improvement using freezing technique to allow adit excavation in a very dense urban area of Washington, D.C.; Ground improvement under existing utilities using Jet Grout Elliptical columns; Hybrid ground improvement system using freezing and jet grouting method to allow the Adit construction in one of the construction sites; Final TBM breakthrough into shaft filled with water; and Unreinforced slurry walls used as support of excavation for the drop shaft construction.

Designer: Brierley Associates; Major Subcontractors: Treviicos, Corman Kokosing, Keller-North America, EnTech Engineering; TBM Manufacturer: Herrenknecht.

Personnel: Owner – DC Water Clean Rivers Project: Carlton Ray (Vice President), Jeff Peterson (Construction Manager); Designer – Brierley Associates: Jeremiah Jezersky (Design Manager); Contractor – Salini Impregilo Healy Joint Venture (SIH JV): Daniele Nebbia (Vice President of Tunneling Operations); Fabio Ciciotti (Project Director); Andrea Sesenna (Project Manager); Flaviano Solesin (Tunnel Construction Manager); Gianluca Pianezze (Sites Construction Manager); Pietro Banov (Design-Build Coordinator).

McCook Reservoir, Des Plaines Inflow Tunnel Walsh Construction Company II, LLC

Work on this $107.77 million project for the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) includes approximately 5,850 lf of tunnel, 20-ft concrete lined finished diameter, approximate tunnel depth of 280 ft, one 12-ft diameter construction shaft, and one 45-ft diameter gate shaft. The tunnel was excavated all through bedrock with the use of a drill & blast method.

The project is approximately 92% complete. Major milestones completed include excavation of construction & gate shaft, excavation and lining of 20-ft diameter tunnel, and connection to Stage 1 of the McCook Reservoir with subsequent tunnel plug when the reservoir became live in 2017. In addition, the two 22-ft x 21-ft steel gates & hydraulic cylinders to control water within the tunnel when it becomes live have been delivered to the site and are currently installed. Gates are now operational and the Contractor has made the connection into the existing live 33-ft tunnel on the North end. The Contractor is currently completing concrete lining work at the north end connection. The Contractor was scheduled to remove the plug on the south end (reservoir side) at the end of January 2022 which will allow flow from the north end to be connected to the existing McCook Reservoir. Final completion is expected in spring 2022.

Unique features of the project include the time constraint of having the south end of the tunnel connected to Stage 1 of the reservoir before the reservoir came on-line at the end of 2017. The other unique feature will be connecting the north end of the proposed tunnel to an existing live 33-ft tunnel that collects combined sewage for the Chicagoland area.

Tunnel & Gate Designer was Black and Veatch Corporation. The mining company in charge for excavation of Stage 1 of the McCook Reservoir was Vulcan Materials (Vulcan & Walsh needed to coordinate their work when the proposed tunnel was connecting into the reservoir). Major subcontractors were Linita Design & Manufacturing Group, Pagoda & Electric Construction Inc., Truck King Hauling, Terrell Materials Corporation, Atlantic Painting Company and Steppo Supply & Construction Inc.

Personnel: MWRDGC: Kevin Fitzpatrick (Design Project Manager), Patrick Jensen (Design Engineer), Carmen Scalise (Construction Project Manager), Tim Nolan (Resident Engineer). Black and Veatch: Faruk Oksuz (Project Director), Cary Hirner (Project Manager) and Mark White (Engineering Manager). Walsh: Mark Fournier (Project Manager), Erik Schneider (Technical Engineer).

Three Rivers Protection and Overflow Reduction Tunnel Project (3RPORT) Salini Impregilo Lane JV

The $188 million Design-Bid-Build project for Fort Wayne City Utilities consists of approximately 24,500 LF of tunnel, 200 to 240 ft deep, excavated by a Herrenknecht slurry TBM, segmentally lined with a 16 ft finished inside diameter. There are three large diameter shafts, ranging from 29 to 69 ft diameter supported through the overburden with a slurry wall, with drill-and-blast excavation through rock. There are 13 small diameter drop and vent shafts, ranging from 2 to 8 ft, excavated by blind-bore drilling, and lined with ductile iron and centrifugally cast fiberglass reinforced polymer mortar pipe. Approximately 720 LF of adits will be driven using drill-and-blast method to connect the TBM tunnel to the drop and vent shafts. The TBM tunnel and adits will be excavated primarily through limestone of the Wabash Formation with anticipated high groundwater inflow in the range of 5,000 gpm to 10,000 gpm at 6.5 bar pressure.

Through the end of December 2021, the project is 78% complete. TBM excavation is completed, the shields of the machine have been buried, and the trailing gear has been removed. The underground adit and deaeration chambers are underway, with pre-excavation grouting and drill-and-blast excavation activities in progress. These adits and chambers will ultimately receive a FRP lining and cast-in-place connection to the main tunnel. The Retrieval Shaft cast-in-place concrete liner is completed; an internal drop shaft and cast-in-place connection structure remain to be performed. The Pump Shaft cast-in-place concrete liner is underway as the base slab has been completed and the liner wall lifts are in progress. The Working Shaft cast-in-place liner remains to be performed. Final completion is expected in May 2023.

Tunnel Designer: Black & Veatch; Construction Manager: Jacobs; Major Subcontractors: CSI Tunnel Systems, Keller – North America, Hardman Construction, Bunn Inc., F.A. Wilhelm Construction, Service Electric; TBM Manufacturer: Herrenknecht.

Personnel: Owner / City of Fort Wayne: Mike Kiester (Manager, City Utilities Engineering); Tunnel Designer / Black & Veatch: Leo Gentile (Senior Project Manager), Matthew Pierce (Project Manager); Construction Manager / Jacobs: Todd Webster (Construction Contract Manager); Contractor / Salini Impregilo Lane JV: Daniele Nebbia (Vice President of Tunneling Operations), Lance Waddell (Project Manager).

White River Tunnel, Lower Pogues Run Tunnel Shea-Kiewit JV

The White River Tunnel is a 30,600-ft, 20-ft, 2-in diameter bored tunnel with an 18-ft finished concrete lining (approximately 250 ft deep). There are two bifurcations in the final alignment and seven CSO connecting structures/deaeration chambers and adits. The Lower Pogues Run Tunnel is a 10,200-ft, 20-ft, 2-in bored tunnel with an 18-ft finished concrete lining, which bifurcates from the White River Tunnel alignment, and includes two CSO connecting structures/deaeration chambers and adits. The work is for Citizens Energy Group's DigIndy project, which is a CSO reduction program including six deep rock tunnels totaling over 28 miles.

Final preparations are underway to commission both tunnels. Ongoing activities include testing of mechanical equipment and instrumentation at each of the drop shaft sites, as well as final grouting of the drop and vent shafts. Contact grouting is also ongoing within the adits and mainline tunnel. In addition, the contractor finished installing a fiber optic network within the tunnel that connects each of the drop shaft sites to both of Citizens’ advanced wastewater treatment plants. Plant personnel can remotely monitor conditions in the tunnel system and operate mechanical gates at each of the drop shaft sites to control tunnel filling.

Personnel – Construction PM: Christian Heinz, P.E.; Assistant Project Manager/ Project Engineer: Percy Townsend; Safety Manager: Kyle Shickles; Field Engineers: Eric Haacke, Zack Heinrich, Kendall Gadd, Chris Monahan, Max Engen. Inspection PM: Sam Cain, P.E. (AECOM). Owner: Citizens Energy Group – Manager, DigIndy Capital Program: Mike Miller, P.E.; Tunnel Construction Supervisor: John Morgan.

Fall Creek Tunnel Shea-Kiewit JV

The Fall Creek Tunnel is a 20,244-ft, 20-ft, 2-in diameter bored tunnel with an 18-ft finished concrete lining (approximately 250 ft deep). There are ten CSO connecting structures/deaeration chambers and adits. The work is for Citizens Energy Group's DigIndy project, which is a CSO reduction program including six deep rock tunnels totaling over 28 miles.

Mining commenced in September 2019 and was completed on April 1, 2020. The Fall Creek Tunnel has nine adits totaling over 5,200 feet and adit excavation is 100% complete. Drop and vent shaft and adit lining is ongoing. Tunnel concrete lining operations commenced in January 2021. Based on the terms of a federal consent decree, the Fall Creek Tunnel must be operational by the end of 2025.

Key Project Personnel – Construction PM: Christian Heinz, P.E.; Assistant Project Manager/ Project Engineer: Percy Townsend; Safety Manager: Kyle Shickles; Field Engineers: Eric Haacke, Zack Heinrich, Kendall Gadd, Chris Monahan, Max Engen. Inspection PM: Sam Cain, P.E. (AECOM). Owner: Citizens Energy Group – Manager, DigIndy Capital Program: Mike Miller, P.E.; Tunnel Construction Supervisor: John Morgan.

Pleasant Run Tunnel Shea-Kiewit JV

The Pleasant Run Tunnel is a 41,472-ft, 20-ft, 2-in diameter bored tunnel with an 18-ft finished concrete lining (approximately 250 ft deep). There are eight CSO connecting structures/deaeration chambers and adits. The work is for Citizens Energy Group's DigIndy project, which is a CSO reduction program including six deep rock tunnels totaling over 28 miles.

Mining commenced in May 2021, and in November 2021 the TBM mined through the 30-foot diameter intermediate shaft approximately 20,000 feet into the alignment. Due to the number of curves in the tunnel alignment, tunneling and muck handling operations will be relocated to the intermediate shaft in order to maximize efficiency of the horizontal conveyor belt system. TBM mining is planned to restart in March 2022. Once complete, the entire 28-mile DigIndy system will have utilized a single Robbins main beam TBM. In addition to 28 miles of hard rock mining, the TBM will have been backed up over nine miles allowing the elimination of multiple launch and retrieval shafts. Based on the terms of a federal consent decree, the Pleasant Run Tunnel must be operational by the end of 2025.

Key Project Personnel – Construction PM: Christian Heinz, P.E.; Assistant Project Manager/ Project Engineer: Percy Townsend; Safety Manager: Kyle Shickles; Field Engineers: Eric Haacke, Zack Heinrich, Kendall Gadd, Chris Monahan, Max Engen. Inspection PM: Sam Cain, P.E. (AECOM). Owner: Citizens Energy Group – Manager, DigIndy Capital Program: Mike Miller, P.E.; Tunnel Construction Supervisor: John Morgan.

Ohio River Tunnel Shea-Traylor JV

The Ohio River Tunnel for the Louisville and Jefferson County Metropolitan Sewer District (MSD) was given NTP on Nov. 8, 2017, and is scheduled to reach Final Completion around summer 2022. The tunnel length is 21,300 ft; Diameter: 22 ft excavated; 20 ft finished; Tunnel depth – 200 ft; Number of shafts – 6. Ground conditions include limestone and dolomite rock, potential fault zones, and potential natural gas zones in the rock.

TBM excavation of the entire tunnel has been completed, with a hole-through date of Sept. 22, 2020. The TBM along with all its trailing decks and appurtenances have been removed from the Retrieval Shaft/Drop Shaft DS06. Gas was encountered only once during tunnel excavation. No groundwater inflow nor any fault zones were encountered during tunnel excavation. Concrete lining of the Tunnel Bifurcation and tail tunnel is complete.

Construction of five out of the six shafts are complete. S-T JV will start working on the Retrieval Shaft/Drop Shaft DS06 after completion of tunnel lining. All adits connecting drop shafts to the main tunnel are complete. Drop Shafts DS01 and DS02 surface structures construction are complete. Along the mainline tunnel, 19,000 ft of the 20,400 ft has been concrete lined as of January 2022. Contact grouting of the tunnel lining is approximately 60% complete.

S-T JV is currently working on lining the Working Shaft; constructing the surface structures for Drop Shafts DS03, DS04, and DS05; concrete lining the mainline tunnel; and contact grouting the tunnel liner.

Tunnel Designer: Black & Veatch; Construction Manager: Black & Veatch; Major Subcontractors: Platt Construction, Steppo Supply, T.E.M., CTL Engineering, Harmon Steel; TBM Manufacturer: Robbins.

Personnel: Greg Powell: MSD Construction Manager; Jacob Mathis: MSD Project Manager; Jonathan Steflik: Black & Veatch Design Project Manager; Mark Bradford: Black & Veatch Design Tunnel Lead; Pete Boysen: Black & Veatch Sr. Construction Manager; Alston Noronha: Black & Veatch Construction Manager; Shemek Oginski: S-T JV Project Manager; Jesse Salai: S-T JV Operations Manager.

Deer Creek Sanitary Tunnel (Clayton Road to RDP) (11731-015.1) SAK Construction

This is a $147.8 million project for the Metropolitan St. Louis Sewer District located in the cities of Shrewsbury, Maplewood, Brentwood, Richmond Heights, Webster Groves, Ladue within St. Louis County.NTP given on Sept. 4, 2017. Substantial completion of the tunnel was achieved in December 2021. Final completion of the tunnel and dewatering pump station is scheduled for November 2022. The tunnel dewatering pump station is currently being constructed under a separate contract.

The project includes 22,800 lf of 19-ft diameter tunnel with 5 drop shafts. The average depth is 120 ft. The project is 99% complete. Excavation of the 40-ft diameter pump station wet well shaft, two 40-ft diameter pump station dry well shafts, and one 35-ft diameter retrieval shaft have been completed. The tunnel excavation was completed on Jan. 28, 2020. The 12-in. thick cast-in-place concrete liner has been completed in the tunnel. Excavation has been completed at each of the five drop shafts and construction of the diversion structures and deaeration chambers are in various stages of completion at each of the five sites.The contractor utilized a horizontal conveyor to convey muck from the TBM heading to the working shaft, a vertical conveyor to convey material from the shaft to grade, and a stacker conveyor to convey the material into a stockpile for removal by truck. Two-pass construction is utilized, with rock dowels and mesh placed as initial support until the excavation was completed, followed by installation of the 12-in. thick cast-in-place concrete liner.

Parties Affiliated with the Project: PARSONS Water and Infrastructure, Inc. (Tunnel Designer); Black & Veatch Corporation (Construction Manager); SAK Construction, LLC (Contractor); Goodwin Brothers Construction Co. (Subcontractor – Near Surface and Surface Construction); Robbins (TBM Manufacturer).

Personnel: SAK – Project Manager; Brent Duncan. Project Engineer; Project Controls; Tom O’Sullivan. Tunnel Division Safety Manager; Jack Lynch. Safety Manager; Cedric Bransford. General Project Supt.; Terry Beesley. Concrete Superintendent; Shayne Peck. Design Project Manager – Nancy Matteoni, Black & Veatch; Construction Manager – Clay Haynes; Metropolitan St. Louis Sewer District – Design Project Manager – Jeff Smith; Metropolitan St. Louis Sewer District- Construction Project Manager – Dan Nichols.

Jefferson Barracks Tunnel SAK Construction

This $63.3 million project for the Metropolitan St. Louis Sewer District includes approximately 17,800 lf of 11-ft excavated diameter tunnel, and installation of a 7-ft diameter fiberglass reinforced polymer mortar carrier pipe and fiber optic conduits in the tunnel.

The tunnel is located adjacent to the Mississippi River, extending southwardly from the Lemay Wastewater Treatment Plant, and is intended to replace an aging system of pump stations, force mains and shallow sewers that convey wastewater to the treatment plant. The tunnel is located approximately 140 to 215 ft below the ground surface in limestone bedrock. Construction is by a main beam TBM launched from an 88-ft diameter shaft. This shaft will serve as the location for a pump station to be constructed under a separate contract. A pre-excavation grouting program was conducted at the launch shaft to minimize inflow from any karstic features which might be encountered during shaft excavation. The TBM will be removed via a 22-ft diameter shaft at the upstream terminus of the tunnel. In addition to the launch and retrieval shaft, there are 14 bored shafts for drop pipes, vent pipes, and fiber optic conduits from the surface to tunnel depth. These shafts pass through a karstic zone located below the level of the Mississippi River. Consequently, these shafts were blind bored.

In May 2019, a karst feature was encountered which caused tunneling work to be suspended after mining about 7,100 feet of tunnel with the 11-foot diameter TBM. In July 2020 after additional investigations, SAK began work to recover the 11-foot diameter TBM. Construction of a 205-ft deep recovery shaft about 200 feet in front of the TBM followed by excavating a tunnel back to the TBM which required hand mining through the karst feature in front of the TBM was completed. The TBM was recovered in late July 2021.A larger, 13.5-foot diameter TBM with the capability of probing and grouting through its face is currently being refurbished by Robbins. Arrival of the new TBM was anticipated to begin late January 2022. The new TBM will be launched from the recovery shaft with tunneling anticipated to resume mid-March 2022. Completion of the entire project is currently anticipated to be at the end of 2023. The Contractor is currently working on construction of the intake structures, base slab and lining of the termination shaft, strengthening the track within the tunnel in preparation for the heavier equipment required for the larger TBM and site preparation to receive the new TBM. Final completion is expected by October 2023.

Karst was identified at the most important geotechnical issue for the project as the bluffs along the Mississippi River are riddled with caves and karstic crevices. The presence of karst influenced the vertical alignment of the tunnel and impacted the design and construction of shafts that pass through the karstic zone.

Tunnel Designer: Jacobs Engineering Group; Construction Manager: Shannon & Wilson; Major Construction Subcontractors: Case Foundation (shafts), ACT (pre-excavation grouting), Williams Tunneling (tunnel construction and carrier pipe installation), Goodwin Brothers Construction (intake construction). TBM Refurbishment: Robbins.

Personnel: Patricia Pride, Project Manager, Metropolitan St. Louis Sewer District; Ray Scherrer, CM Program Manager, Metropolitan St. Louis Sewer District; William Haag, Design Project Manager, Jacobs Engineering Group; Andrew Bursey, Lead Tunnel Designer, Jacobs Engineering Group; Thomas Abkemeier, CM Project Manager, Shannon & Wilson, Inc.; David Donovan, Resident Project Representative, Shannon & Wilson, Inc.; Dan Swidrak, Project Manager, SAK Construction; Terry Beesley, General Project Supt.; Jack Bragg, Project Superintendent, SAK Construction; Jack Lynch, Tunnel Division Safety Manager, SAK Construction; Zach Meyer, Safety Manager, SAK Construction.

Lower Meramec Tunnel (11746) SAK Construction LLC

This is a $174 million project for the Metropolitan St. Louis Sewer District (MSD) comprising 35,903 ft (6.8 miles) of 11-ft excavated diameter, 8-ft inside diameter, 78 to 286 ft deep sanitary sewer tunnel which is expected to be mined utilizing a TBM entirely within limestone, shale and dolomite rock with two required construction shafts and six drop structures. The project is approximately 9% complete. The Contractor has completed drilling the drop and vent shafts, installed secant piles at the termination TBM retrieval shaft and completed excavation of the tail and starter tunnels. The Contractor has begun excavation of the termination TBM retrieval shaft and installation of the upper portion of the concrete lining at the starter shaft.

This project is an extension of the previously constructed Baumgartner Tunnel Project which was 20,200 ft long with an excavated 12.5-ft diameter. Bedrock conditions anticipated to be encountered consist of the Warsaw Formation and the Burlington-Keokuk Limestone. The Warsaw Formation is composed primarily of limestone and shale with small amounts of chert whereas the Burlington-Keokuk Limestone includes limestone and abrasive chert which, in places, composes up to 40% to 60% of the rock mass.

Tunnel Designer is WSP as a subconsultant to HDR Engineering, Inc. The Construction Manager for the project is Black & Veatch.

Personnel: Metropolitan St. Louis Sewer District – Design Project Manager: Jerry Jung; Construction Project Manager: Ray Scherrer. Design Project Manager: Doug Hickey, HDR. Tunnel Design Engineer: Everett Litton, WSP. Construction Manager: John Deeken, Black & Veatch. SAK – Project Manager; Brent Duncan. Project Engineer; Spencer Miller. Project Controls; Tom O’Sullivan. Tunnel Division Safety Manager; Jack Lynch. Safety Manager; Cedric Bransford. General Project Supt.; Terry Beesley. Project Superintendent; Shayne Peck.

Shoreline Storage Tunnel McNally/Kiewit SST JV

The Shoreline Storage Tunnel, a $201.58 million project for the Northeast Ohio Regional Sewer District, will enable the District to meet specific combined sewer overflow (CSO) control requirements of Control Measure 7 as identified in Appendix l of the Consent Decree. When constructed and operating with the future Shoreline Consolidation Sewer project, the Shoreline Tunnel System will reduce CSO by an estimated 350 million gallons annually from 12 permitted CSO locations that are direct tributaries to Lake Erie. NTP was issued on July 19, 2021, with a duration of 1,770 days.

The project includes the construction of the following:

This is the Sewer District's first large diameter soft ground tunnel.

A related project, the Shoreline Consolidation Sewer, is 5,100 LF of 6-ft diameter soft ground tunnel to connect to upstream end of Shoreline Storage Tunnel (Kokosing Industrial, Inc. is prime contractor).

Design: McMillen Jacobs Associates. TBM Manufacturer: Herrenknecht. Anticipated Subcontractors: Nicholson Construction, Mersino Dewatering, Karma Materials, Northstar Contracting, 330 Williams Landscaping LLC, 7NT Enterprises LLC, Valley City Supply, Mack Concrete, Chieftain Trucking & Excavating, DiGioia Suburban Excavating LLC, Petty Group LLC, Cook Paving & Construction Co. Inc., Marra Service Inc., VIP Electric, Great Lakes Pipeline Services, Mars Electric Company Inc.

Project Personnel: Jack McKeigan, Construction Coordinator, NEORSD; Bob Auber, Construction Manager, NEORSD; Ryan Sullivan, Construction Supervisor, NEORSD; Chris Lynagh, Contractor, McNally/Kiewit SST JV; Ian Danielson, RPR & Designer, McMillen Jacobs Associates; Rick Vincent, Design Manager, NEORSD; Charles Huse, Project Manager, NEORSD.

Westerly Storage Tunnel Jay Dee Obayashi JV

Jay Dee Obayashi JV is building this $135 million project for the Northeast Ohio Regional Sewer District (NEORSD) as part of the Project Clean Lake CSO abatement program. It includes 2 miles of 25-ft finished diameter tunnel, approximately 200 to 250 ft deep. Recent activities include:

The Westerly Storage Tunnel will be online/activated when the Westerly Tunnel Dewatering Pump Station is complete in 2023.

Tunnel Designer: Stantec Mott MacDonald Westerly JV; Construction Manager: Owner managed (NEORSD); Major Subcontractors: DiGioia-Suburban Excavating (open cut and misc. site work), Nicholson Construction Company (Shaft SOE), Marra Services Inc. (shaft excavation at two sites), Northstar Contracting Inc (concrete structures); TBM Manufacturer: Lovsuns.

Project Personnel: Project Sponsor (Jay Dee Obayashi JV): John T. DiPonio; Project Manager (Jay Dee Obayashi JV): Nate Long; Project Engineer (Jay Dee Obayashi JV): Lisa Smiley; General Superintendent (Jay Dee Obayashi JV): Phil Rhodes; Jack MacKeigan, Construction Coordinator (NEORSD); Bob Auber, Construction Manager (NEORSD); Buck Depew, Construction Supervisor (NEORSD); Rick Vincent, Design Manager (NEORSD); Steve Janosko, Project Manager (NEORSD); Ben DiFiore, RPR & Designer (Mott MacDonald).

Deputy Director of Engineering & Construction (NEORSD): Doug Gabriel; Construction Manager (NEORSD): Robert Auber; Senior Construction Supervisor (NEORSD): Richard Depew.

Integrated Pipeline Project – Sections 19-1 and 19-2 IPL Partners

The Integrated Pipeline Project – Sections 19-1 and 19-2 is a $21 million project for the Tarrant Regional Water District. NTP was issued Oct. 19, 2021, with an estimated completion of Jan. 12, 2023.The project comprises 2,000 lf of 10-ft excavated diameter with 10 different tunnels crossing TXDOT roads each with launch and receiving shafts (20 shafts) at shallow depths (under 40 ft). Excavation is expected to be through sands and clays using a boom-in-shield Tunneling machine. To date crews have completed 38% of tunnel footage and completed five of the 10 tunnel crossings.

Designers: HDR Engineering and BGE Inc.; CM: Caledonia Construction Management; TBM Manufacturer: Custom fabricated machine by Southland Contracting Inc.

Project Personnel: IPL Partners Operations Manager: Kent Vest; IPL Partners Project Manager: Jose Jimenez; IPL Partners Project Engineer: Hossein Mirenayat; IPL Partners Superintendents: Rod Fisher and Rick Leever.

Mill Creek/Peaks Branch/State Thomas Drainage Relief Tunnel Project Southland/Mole Joint Venture

The Mill Creek/Peaks Branch/State Thomas Drainage Relief Tunnel Project for the City of Dallas is a $206.7 million job that consists of: 26,385 lf of tunnel (32-ft, 6in. excavated diameter, 30-ft finished diameter); 8 Intake Shafts (ranging from 120 vf to 200 vf depth); 6 lateral tunnels excavated by roadheader or excavators/breakers; and a dewatering station. The project is being built with a Main Beam TBM through Austin chalk.

Crews have completed excavation of 7 shafts with 1 shaft remaining (shafts range from 22 to 35 ft diameter and 110 to 190 ft deep). There are a total of 8 Shafts on project (5 Intake Shafts, 1 Outfall Shaft, 1 Dewatering Station Shaft, and 1 Access Shaft).

To date, 19,500 lf of tunnel excavation has been completed with the Main Beam TBM (10,000LF at 37-ft, 7-in. and 9,500LF at 32-ft, 6in.). Currently the TBM is mining at 32-ft, 6-in. diameter with 6,500LF remaining.

The lining is a 15-in. thick cast-in-place final concrete liner. There are 6 working sites within city environment with tunneling under city infrastructure (including State Highways, Light Rail Tunnels/Surface Tracks, Rail Roads). The project is expected to be complete in March 2023.

Owner: City of Dallas; Lead Designer: HALFF; Tunnel Designer: COWI; CM: Black and Veatch; TBM Manufacturer: The Robbins Company; Contractor: Southland Mole JV (Southland Contracting & Mole Constructors); Subcontractor: Oscar Renda Contracting Inc.; Contractor Design Engineer: Aldea Services.

Personnel: SMJV Operations Manager: Kent Vest; SMJV Senior Project Manager: Quang D. Tran, P.E.; SMJV Project Manager: Nick Jencopale; SMJV QC Manager: Matt Jackson; SMJV General Superintendent: Mike Clingon; SMJV Senior Project Engineer: Jose Ortiz, P.E.; SMJV Field Engineers: Jason Lipp/Kade Conner.

Ship Canal Water Quality project LANE Construction

The $255 million Ship Canal Water Quality Project (SCWQP) Storage Tunnel Contract for Seattle Public Utilities (SPU) is comprised of 13,939 lf of 18-ft, 10-in. ID segmentally lined tunnel using a 21.5-ft diameter pressurized face tunnel boring machine (TBM) with tunnel depths ranging from 35 to 85 ft to top of tunnel, and a conveyance pipe casing under the Ship Canal installed via a curved microtunnel drive, 646 lf and 94-in. diameter.

There are five shaft sites: one slurry wall shaft at the West Shaft site in Ballard (tunnel launch site); three secant pile shafts at the Fremont site, Queen Anne site, and East Shaft site in Wallingford (tunnel exit shaft); and one drilled shaft using a steel casing at the East Ballard site. Anticipated ground conditions along the tunnel alignment consist of a highly variable mix of glacially over-consolidated soils.

The construction project is 45% complete (as of the end of December 2021). All five shafts are complete and both tunnel boring machines launched. The 21.5-ft diameter TBM, ("Mudhoney"), has completed approximately 1,000 ft (7%) of the tunnel drive that begins at the Ballard neighborhood eastward along the north side of the Ship Canal toward the Wallingford neighborhood. The 10-ft diameter MTBM will complete its journey from Fremont southward under the Ship Canal toward the Queen Anne neighborhood by end of May 2022. Additionally, during this period crews will install conveyance pipe and below grade vaults.The TBM was successfully launched using a ‘steel bell’ structure to simulate regular EPB TBM tunneling conditions at the face and around the entire tunneling envelop before breaking out of slurry wall and into glacial deposited ground, instead of any soil improvement at the launch shaft.

The TBM launch drive is longer than typical launches using umbilicials. The launch drive using umbilicials was 830 ft which is the longest in the history of LANE construction. The launch drive was completed on October 2021. The launch set up also includes temporary gantries and conveyor belt. The machine is currently undergoing final assembly and commissioning as of December 2021.

The final setup includes muck cars, rotary dump, car passer and car mover which will be used for the mucking operations in the final configuration. Final project completion is expected in August 2023.

Tunnel Designer: McMillen Jacobs Associates; Construction Manager: Jacobs Engineering; TBM Manufacturer: Herrenknecht. Major Subcontractors: Shaft Construction – Malcolm Drilling Co.; Microtunneling – Northwest Boring Co. Inc..; Mechanical and Concrete Structures – Prospect Construction Inc.; Electrical – Chau Electric; Trucking – Grady Excavating Inc.; Segments: CSI.

Personnel: Owner (SPU): Keith Ward: SCWQP Executive; Cynthia Blazina: SCWQP Construction Manager; Stephanie Secord: SCWQP Project Manager; Roger Mitchell: SCWQP Supervising Resident Engineer. Lane Construction: Daniele Nebbia: Vice President of Tunneling Operations; Project Director: Fabrizio Fara; Technical manager: Basilio Giurgola ; Construction Managers: Raffaele Aliberti, Alessandro Marini.

Kemano T2 Tunnel Project – Upstream Works Barnard Constructors of Canada, LP

This project for Rio Tinto is located in Kemano, BC, 74 km southwest of Kitimat. NTP was issued July 1, 2020; with an estimated completion in 2022.

Construction for the 16-km-long KT2 began in the early 1990s. The project is currently in its final phase, which involves excavation of 7.6 km of new tunnel and refurbishment of an 8.4 km portion of the second tunnel that was constructed in the 1990s. In July 2020, Barnard Constructors of Canada, LP was awarded the Upstream Works portion of the Kemano T2 Tunnel Project to construct the remaining approximately 4 km of the 7.6 km new tunnel. The tunnel is being excavated by a 6.56-diameter Herrenknecht single-shield hard rock TBM and includes installation of precast concrete tunnel lining.

Barnard's scope of the project is approximately 88% complete and on Oct. 11, 2021, the TBM holed through into the T2 Intake Stub Tunnel built in the 1950s at the Tahtsa Lake Intake. Since hole-through crews have been working to disassemble the Herrenknecht tunnel boring machine (TBM), removing gantries, dismantling the cutterhead and removing it through the intake gate slot shaft with a 14-ft x 3-ft opening and proof grouting the PCTL tunnel.

In January, crews completed proof grouting of the tunnel, installed a new independent rail spur specifically for TBM gantry, bridge, erector and main drive removal back through the new tunnel, and removed the California switch and MineARC refuge chambers to allow these large TBM components to be removed from the tunnel.

With the gantries removed, the Barnard team is preparing for the last stages: removal of the cutterhead main drive and cleaning of the tunnel. All rail and temporary utilities must be removed, and the tunnel cleaned to allow the shotcrete transition from the bored PCTL tunnel to the drill and blast cast-in-place concrete modified horseshoe T2 Intake Stub Tunnel prior to watering up.

Engineer – Hatch Ltd.; TBM manufacturer and Technicians – Herrenknecht.

Project Personnel: Owner: Rio Tinto: Alex Jones – Project Manager, Gregory "Alf" Garnett – Underground Area Manager. EPCM: Hatch: Riley McMillan – Lead Field Engineer, Luis Corgo – Deputy Underground Area Manager, Shawn Tucker – Deputy Underground Area Manager, Daniel Jezek – Lead Underground Engineer and Engineer of Record, Gary Kramer – Engineer of Record. Barnard: Project Managers: Jimmy McGauley, Ryan Eitutis; General Superintendents – Patrick Finn, Tom McDowell. Lead Engineers: Matthew Whittle, Michael Zenker. Construction Superintendents – Matthew Ulizio, Ross McLean, Craig Arnes, Mike Gilbertson, Govar Hayder, Chad MacDonnell, Maurizio Matta. Field Engineers – Brett Campbell, Michael Delaney, Guillermo Charles-Barrera, Michael Karl, Josh Richard, Andrew Rafuse, John Doerr, Brent Chalker.

Second Narrows Water Supply Tunnel, Burrard Inlet Crossing Traylor-Aecon General Partnership

The Second Narrows Water Supply Tunnel for the Greater Vancouver Water District (Metro Vancouver) is a $286 million project that will improve reliability and increase capacity for Metro Vancouver to deliver drinking water throughout the Vancouver area. Notice to Proceed was issued Jan. 15, 2019, and final completion is expected in the fall of 2023.

Project consists of two shafts (18mØ x 68m and 10mØ x 110m) on either side of the Burrard Inlet that are connected by 1,100 m of 5.8m ID, 6.7m excavated diameter segmentally lined tunnel that was constructed with a mix shield TBM at face pressure up to 7 bar with allowance for hyperbaric interventions via saturation diving. Ground improvement includes a safe haven constructed using ground freezing 425 m into the drive. Three permanent water mains (2 @ 2.438m, 1 @ 1.524 m) will be installed within the tunnel, up both shafts and into large underground valve chambers atop each shaft.

The TBM holed through at the South shaft in September 2021 and machine retrieval was complete by November 2021. Tunnel cleaning and invert concrete placement were complete in early December 2021 in advance of production pipe installation and welding that started in January 2022 and will continue through the spring.

Excavation and shoring for the south valve chamber is well underway with concrete construction, mechanical work and site retaining wall to begin in February 2022. Pre-clearing for the sheet pile shoring at the North valve chamber is also underway to be followed by sheet pile installation,excavation and tremie concrete placement through the summer of 2022.

Major Subcontractors: Herrenknecht (TBM manufacturer); Schauenburg (slurry treatment plant provider); Malcolm-Petrifond JV (slurry wall); Keller North America (ground freezing); Ballard Marine Construction (hyperbaric services); Northwest Pipe (pipe supplier); MSE Precast (precast segment supplier); Jewel Holdings Ltd. (pipe welding and lining repair); Henry Foundation Drilling (valve chamber shoring); Southwest Contracting Ltd. (civil works).

Owner: Metro Vancouver (PM: Mark Qian); Tunnel Designer: McMillen Jacobs (Andrew McGlenn); Construction Manager: Mott MacDonald/Jacobs (CM: Ian Whitehead, DCM: Ken Rosenberg); Contractor: Matt Burdick, Joe Waller, Erica Frederickson, Brian McInnes.

Stage 2 LRT Project – O-Train East and West Extension Project East-West Connectors (EWC)

The Stage 2 Confederation Line east and west extensions project is a $2.57 billion (CAD) design-build-finance project for the City of Ottawa being built by East-West Connectors (EWC), joint venture comprised of Kiewit, Eurovia and VINCI (KEV).

The west extension includes two cut-and-cover tunnels:

Construction of the Parkway Tunnel began in 2020. Before it could begin, traffic was shifted, and underground utilities were relocated. Work is being staged to minimize impacts on pedestrians, cyclists, and local traffic; requiring five temporary bridges installed to maintain connectivity during construction.Excavation began at the top surface level, and support walls are being installed as the tunnel gets deeper. Once excavation and construction of the concrete tunnel structure is complete, localized backfill and restoration of the surface will begin.

As of January 2022, excavation of the Parkway tunnel is progressing well. Approximately 218,000 cubic meters or 44% of the total quantity, has been excavated, and 80% of the pile drilling has been completed, as well as 100% of slurry wall installed along the Sir John A. Macdonald Parkway. 98 percent of support of excavation (SOE) piles have been installed at Pinecrest/Connaught.

The Parkway tunnel will travel under federally owned lands and a City of Ottawa park in order to preserve recreational opportunities and community linkages. When construction is complete on the Parkway tunnel, Byron Linear Park will be enhanced to include more trees, less pavement, more public art, and additional plaza space for local events.

The Connaught Tunnel will travel under a residential neighborhood. Overall, the Stage 2 LRT O-Train East and West extensions is a signature project in Canada's national capital, funded by three levels of government. There is close, ongoing collaboration with all stakeholders and the public, as building a large infrastructure project in an urban environment can be disruptive.

Excavation is facilitated by the various use of SOE, depending on the ground conditions encountered. Types of SOE include slurry walls, secant pile walls and soldier piling and lagging.

The estimated date of completion is 2025.

Key Facts and Statistics

Design engineering services are being provided by WSP Canada and Hatch Ltd.

Personnel: Chris Loeffler, Senior Vice President and Project Director, Kiewit Infrastructure Corporation; Gwyon Nelson, Project Director, Kiewit Eurovia Vinci.

Stage 2 LRT Project – O-Train South Extension Project TransitNEXT

The $1.6 billion Stage 2 Trillium Line extension is being built by TransitNEXT, a wholly owned subsidiary of SNC-Lavalin, for the City of Ottawa. The Dows Lake Tunnel is a critical piece of infrastructure along the Trillium Line alignment. Originally built and owned by Canadian Pacific Railway (CPR), it opened for operation in 1964 as a rail tunnel to accommodate freight trains. The tunnel was converted for use by OC Transpo in 2001 for the O-Train.

As part of the South Extension Project, TransitNEXT will address several historical challenges through design and construction of the tunnel's upgrades, including:

Prior to construction, detailed inspections of the Dows Lake Tunnel were conducted. A virtual 3D Building Information Model (BIM) of the entire tunnel including the pump house was created to ensure a well-coordinated design and avoid issues during construction.

The length of the tunnel is 578 m with 23 reinforced concrete box segments separated by expansion joints. The height of the tunnel is approximately 6.7 m from the top of the rail. The width of the tunnel is approximately 5.1 m.

Rehabilitation of the Dow's Lake Tunnel is nearing completion as crews conclude waterproofing of tunnel expansion joints, concrete repair, and additional steel reinforcement. Work is currently underway to upgrade the drainage system and modernize the tunnel ventilation system, trackwork, standpipe system, communication systems, and emergency walkway to align with National Fire Protection Association (NFPA) -130 standards. TransitNEXT is currently installing brackets for the power supply to the tunnel ventilation system. Tunnel work is estimated to be completed in the fall of 2022.

Southland | Astaldi Joint Venture

The $300 million Ashbridges Bay Treatment Plant Outfall project for the City of Toronto consists of a 16-m diameter shaft, 85 m deep; 3.5 km of 8-m diameter TBM excavated tunnel; 7-m ID Precast Concrete segmental lining; and 50 of 1-m diameter risers from tunnel (marine work). The expected ground is Georgian Bay shale.

The project is currently 70% complete. Shaft excavation is complete for tunnel activities. The 8-m diameter segmental tunnel is over 90% complete. Offshore Risers installation is complete. The 50 off-shore risers installed in Lake Ontario are connected to the TBM excavated tunnel from within the precast segmental lining.

Consultant & Designer: Hatch with Jacob & Baird; Major Subcontractors: Johnson Bros. Corp (Off-shore work including Riser installation).

Personnel: Contractor: Southland | Astaldi JV; Project Director (Kent Vest); Project Manager (Joe Savage); Deputy Project Manager (Francisco Urrutia); General Superintendent (Curtis Bahten); Underground Superintendent (Jeff Reagan).