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 2021 issue of the print edition.

Joint Water Pollution Control Plant Effluent Outfall Tunnel Dragados USA

NTP for this $630 million project for the Los Angeles County Sanitation Districts was issued April 8, 2019, with 1,953 working days to complete the work and an estimated completion date of December 2026. The outfall project, which will serve the sanitation needs of approximately 5 million people in 73 cities in the Los Angeles area, is part of the Sanitation Districts’ Clearwater Program, which includes the the construction of a tunnel approximately 7 miles long and 21.5 ft in excavated diameter (18 ft ID) to convey disinfected, secondary-treated effluent from the Sanitation Districts’ Joint Water Pollution Control Plant (JWPCP) located in the City of Carson to an existing ocean discharge system at Royal Palms Beach in San Pedro in the City of Los Angeles.

The tunnel will provide better seismic resiliency, provide additional capacity for population growth and storm events, and will provide redundancy for the two existing tunnels that were constructed in 1937 and 1958, and which have not been inspected in nearly 60 years. The tunnel will be constructed by a slurry single pass TBM beginning at the JWPCP Shaft Site (entry shaft) and ending at Royal Palms Beach (exit shaft). The tunnel alignment will vary in depth from approximately 50- 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 proposed 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.

The tunnel lining will consist of bolted and gasketed precast concrete segments. Tunneling will go through splays of the Palos Verdes Fault Zone where 16-ft diameter steel liner will be used within the 18-ft diameter concrete segments to accommodate displacement from seismic events at two locations. When in operation, the tunnel will be under hydrostatic pressure. In the first half of the alignment, internal pressure will exceed the external pressure and post-tensioning of the concrete segmental liner will be necessary. To offset the “hoop stress” developed from internal pressure, a post-tensioning system consisting of internal steel tendons along the circumference of the concrete liner was specified. This post tensioning design is unique and has only been used a few times in the world, but never before in North America. In the second half of the alignment, the hard rock around the tunnel will offset the internal pressure, and post-tensioning will not be required.

Work at the JWPCP Shaft Site started in summer 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. Jet grouting activities for the tail tunnel, starter tunnel, and three safe havens is ongoing with an anticipated completion date of early 2021. 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. The Contractor will be 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.

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.

Key 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 – Rene Reichl, 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.

The Mountain Tunnel for the San Francisco Public Utilities Commission is a critical lifeline asset through which the SFPUC conveys 85% of its water from the Hetch Hetchy Reservoir within Yosemite National Park in the Sierra Mountains to 2.7 million wholesale and retail customers in the San Francisco Bay Area. The existing tunnel is 18.9 miles long, including 11.5 miles of 12.5-ft diameter concrete lined section and 7.4 miles of unlined, approximately 14-ft diameter section in granitic rock.

The objectives of the Mountain Tunnel Improvements are to rehabilitate the tunnel and make improvements to extend the useful life of this asset for the next 100 years. The scope of work includes: concrete lining repairs, contact grouting, approximately 5,000 lf of concrete invert paving, a new tunnel portal and 1,000 lf by 14-ft diameter adit tunnel at Priest Portal, two new shafts of 100-ft and 150-ft depth and connector tunnel sections to the existing tunnel, two 72-in. control valves plus four 72-in. insolation valves, an approximately 700-ft by 14-ft diameter bypass tunnel extension of South Fork Siphon below the Tuolumne River, approximately 1,500 lf of steel pipe tunnel lining, adit bulkhead improvements at Early Intake, construction staging areas for spoils fill sites and office trailers, access road/slope stabilization for safer access, water treatment plants for construction water discharge, environmental permit compliance, and other site improvements and site restoration. Since most of the excavations and even some slope stabilization will occur in hard rock, it is anticipated that controlled detonation will be used in addition to mechanical excavation methods.

The Design and Bid/Award phases were completed and Michels Tunnel was awarded the $138.9 million construction contract on Oct. 13, 2020. NTP construction was anticipated in early January 2021 and groundbreaking in February 2021. Completion is expected by December 2026.

This project will require five winter season tunnel outages of 60 to 100 days duration each in order to do the repairs and other work inside the tunnel, and to construct the tie-ins connections between the existing tunnel and the new improvements. The new tunnel adit and new shaft housing the flow control valves at Priest Portal, and the new siphon extension at South Fork will require tie-ins.

McMillan Jacobs Associates was the tunnel designer of record. The construction manager will be the SFPUC’s Construction Management Bureau with supplemental resident engineer, construction management and inspection staffing provided by AECOM. Major Michels subcontractors include Apex Rockfall Mitigation, Kroner Environmental, Schrader Mechanical, Cody Builders Supply, Geostructural Engineering, Inc., and Renesco, Inc.

Key Project Personnel: SFPUC – Regional Project Manager: David Tsztoo, PE; Regional Project Engineer: Tedman Lee, PE ; Project Engineer: Joseph Buitrago, PE (acting); Regional Construction Manager: Jerry Malone. McMillan Jacobs – Project Manager: Rene Fippin, Principal, PE, GE; Project Mgr.(Constr.): Jennifer Sketchley, PE; Tunnel Engineer: Glenn Boyce, Principal, PE, GE; AECOM – Contract Manager: Steven Tidwell, Vice President; Resident Engineer: Bob Mues; Lead Inspector: Thomas (Bud) DeGrio. Michels Tunneling – Project Sponsor: Jim Stevens, Project Manager, Ed Whitman, Project Engineer, Dave McCallum, Project Superintendent, Ron Klinghagen, Tunnel Superintendent, Jason Keys.

Regional Connector Transit Project Regional Connector Constructors (Skanska-Traylor JV)

The Regional Connector Transit Project is in the heart of downtown Los Angeles in a congested urban environment where construction encounters numerous challenges and requires coordination with multiple third parties. The Regional Connector Transit Project will connect three operating rails systems, the Metro A (Blue) and E (Expo) lines on the West and the L Line (Gold) on the East. When complete, transit riders will no longer need multiple transfers and can travel north-south and east-west on the same system. Significant progress is expected in 2021 in anticipation of the construction completion in the summer and opening to the public in the fall of 2022.

The tunneling portion of the $1.8 billion Regional Connector Transit Project for the Los Angeles County Metropolitan Transportation Authority involved 5,795 ft of 21-ft diameter twin tunnels. The ground conditions range from alluvium soils to clayey siltstone of the Fernando formation with the groundwater table generally above the tunnel alignment. Pressure balance tunneling utilizing an EPB TBM was required, along with precast concrete segments with double gaskets as the tunnel lining system. The tunnel depth (cover) ranges from 25 ft to approximately 120 ft and crosses below the existing Metro Red Line heavy rail tunnels with less than 7 ft of clearance. The Regional Connector includes approximately 2,100 ft of cut-and-cover and retained cut guideway, a 300 ft crossover cavern excavated by Sequential Excavation Method (SEM) techniques, and three cut-and-cover subway stations. The bored tunnels were excavated by one TBM concurrently with the construction of the three stations, requiring coordination between the cut-and-cover operations and TBM tunnel excavation. The bored tunnels were successfully completed on time in January 2018 with the SEM cavern excavation completed in March 2019.

Structural concrete at the three underground stations and cut-and-cover guideways throughout the project is significantly advanced and will be completed during the 2nd quarter 2021. With provisions being incorporated into the Historic Broadway Station to accommodate the overbuild of a mid-rise commercial structure, station construction will extend through the end of 2021. Backfilling of the 1,400 ft of the cut-and-cover tunnel structure along Flower Street is advancing in preparation for street reconstruction, which will extend through the end of 2021.

Presently, the focus throughout the alignment continues to be on the installation of trackwork. The placement of two track crossovers; the first in the SEM crossover cavern and the second in the Wye structure where the project connects to the existing L Line (Gold), is scheduled to continue through the 1st quarter 2021. While this connection is made, a segment of the operating L Line has been taken out of service with transit passengers being shuttled around the outage on transit busses. As trackwork installation advances, emphasis will turn to systems installation, vertical circulation and architectural finishes. A significant investment has also been made to incorporate public artwork into the station architecture.

Contractor testing of installed systems is scheduled to begin late this year which will be followed by turnover of the facilities to Metro Operations for operator training and testing period. The completion of the Regional Connector will require significant changes in how LA Metro operates its light rail system as three existing lines are integrated into two systems. Preparations are already underway in anticipation of these operational changes. Overall, the project is progressing on schedule and is scheduled to begin revenue operations during the 3rd quarter 2022.

Other parties affiliated with the project – Tunnel Designer for the Contractor: Mott McDonald; Preliminary design was completed by CPJV (AECOM/ WSP), which is also performing design services during construction, and Metro’s Construction Management Consultant is Arcadis.

Key Project Personnel – Metro Project Executives: Gary Baker, Project Manager; Michael Harrington, Engineering Manager; Sy Morales, Construction Manager; Metro Design Consultants: (AECOM/WSP), William Hansmire, Tunnel Design Manger; Metro Construction Management Consultants: (Arcadis), Jaydeep Pendse, CMSS Manager; Contractor Project Executives (Regional Connector Contractors RCC): (Skanska) Mike Aparicio, Mike Smithson, Greg Zwiep, Justin Waguespack; (Traylor), Christophe Bragard.

Westside Purple Line Extension Section 1 Skanska/Traylor/Shea JV

The Westside Purple Line Extension Project is a 9-mile long project that consists of three Sections. Section 1 is a 3.92-mile long subway alignment with three stations being constructed under Wilshire Boulevard in gassy ground and tar sands with prehistoric fossil deposits.

NTP for the $1.636 million design-build contract was issued on Jan. 12, 2015, with service expected in 2023. The twin Herrenknecht EPB TBMs have completed the second stretch of tunneling from Wilshire/La Brea to Wilshire/Fairfax through the tar sands. Elsie and Soyeon, the Section 1 TBMs, are currently tunneling to the west under Wilshire Boulevard and should be arriving at Wilshire/La Cienega Station in June. 10 of the 23 crosspassages have been excavated. Permanent rail activities are planned to start April 1.

The scope of work includes 17,900 ft of twin-bore tunnel: Reach 1 is 9,600 lf between Wilshire/La Brea Station and Wilshire/Western TBM retrieval shaft; Reach 2 is 4,400 lf between Wilshire/La Brea and Wilshire/Fairfax Stations; and Reach 3 is 3,300 lf between Wilshire/Fairfax and Wilshire/La Cienega Stations. There is also 600 lf of tail track at Wilshire/La Cienega Station.

The tunnel is 18-ft, 10-in. in diameter with 12-in. thick precast concrete lining. Depth varies from 40 ft and 100 ft. The alignment includes three stations and the western retrieval shaft and 23 cross passages. Cross-passages are planned to be mined by the sequential excavation method using variety of localized ground support systems.

Tunnel Designer: PTG/CH2M; Construction Manager: WEST JV (Stantec/Jacobs Engineering/AECOM); Major Subcontractors – TBM Manufacturer: Herrenknecht; Precast: Traylor Precast; Support of Excavation/Piles: Condon Johnson; Jet Grouting: Malcolm Drilling; Geotechnical instrumentation: Group Delta; Dewatering: Moretrench; Standpipe: Link Nielsen.

Silicon Valley Clean Water Gravity Pipeline project Barnard Bessac Joint Venture

This is a $206.7 million progressive design-build project for the Silicon Valley Joint Powers Authority. Construction NTP was issued in November 2018, with an estimated substantial completion date of July 2022.

The project comprises 17,400 linear ft of tunnel with two independent tunnel drives with 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. The geology comprises medium to stiff clay with layers of sand and silty sand geology. Crews are using EPB tunneling and will install a second pass liner with 10-ft and 11-ft GFRP pipe.

To date, the project is 65% percent complete, including completion of the first tunnel drive (5,200-ft). Other recent activities include:

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

Key Project Personnel: Project Manager: Jack Sucilsky; General Superintendent: Mike Hanley; Assistant Project Manager: Glenn Strid; Superintendent: Mike Gilbertson.

PAR 1232 Second Creek Interceptor Bradshaw Construction Corporation

Bradshaw Construction Corporation will soon begin work on the PAR 1232 Second Creek Interceptor project in Denver. The wastewater interceptor will include eight trenchless crossings totaling over 4,100 lf, which Bradshaw will perform by microtunneling. Tunnel crossings will range from 48-in. steel casing to 73.5-in. steel casing, with drive lengths reaching 1,500 lf on the longest crossing. FRP from 30 to 60 in. will be installed and backfilled once tunneling operations are completed. The tunnels will be installed out of steel sheeted shafts, installed by Lawrence Construction Company. The project geology will consist of multiple mix face conditions with claystone overlaid by coarse and fine alluvium, underneath the water table. Tunnels will pass underneath roads, highways, UPRR and BNSF tracks. The project members include the Metro Wastewater Reclamation District (Owner), HDR Engineering Inc. (Engineer), Garney Construction (CMAR), and Bradshaw Construction Corporation working as tunneling subcontractor.

Project Information: Jordan Bradshaw – Project Manager; Jordan.bradshaw@bradshawcc.com.

Thornton Water Project Bradshaw Construction Corporation

Bradshaw Construction Corporation is currently installing two rib-and-board tunnels for the Thornton Water Project in Johnstown. The 68-in. OD tunnels (235 lf and 250 lf) are being installed behind an Akkerman 540C conventional TBM. Tunnel geology consists of uniform claystone, with the tunnels passing underneath the Little Thompson River and Cache La Poudre River. 42-in. welded steel pipe will be installed after tunneling is completed to facilitate the raw water transmission line. The tunnels are being constructed out of 26-in. ID secant piles shafts, and recoverd in 18-in. ID secant pile shafts, installed by Schnabel Engineering. The project members include the City of Thornton (Owner), Burns & McDonnell (Engineer) and Scott Contracting, Inc. (General Contractor), with Bradshaw Construction Corporation working as tunneling subcontractor.

Project Information: Jordan Bradshaw – Project Manager; Jordan.bradshaw@bradshawcc.com.

Upper North Oconee – Phase 2B Trunk Sewer Replacement Bradshaw Construction Corporation

Bradshaw Construction Corporation has begun construction in Athens-Clarke County for re-alignment of the gravity sewer line. Bradshaw has completed the first tunnel drive spanning 116 ft under the Athens Line Railroad, in which 60-in. steel casing was jacked behind a Herrenknecht AVN 1200 MTBM. The second tunnel will require two separate tunneling methods due to a transition in ground conditions. A NATM starter tunnel was excavated out of the shaft 48 lf until the heading transitioned into competent rock, where a rock head TBM manufactured by Robbins will take over and mine approximately 1,100 ft through competent rock. The rock TBM will curve under a busy section of Georgia SR 10, and be recovered in a liner plate recovery tunnel and maneuvered into the receiving pit. After both tunnels are complete, 36-in. ductile iron gravity sewer pipe will be installed and backfilled. Ground conditions are anticipated to transition between partially weather rock and granite. The project is scheduled to be completed in March 2021. Project members include Athens-Clarke County (Owner), Garney Construction (General Contractor). and Bradshaw Construction Corporation working as the tunneling subcontractor.

Project Information: Chris Flanagan – Project Manager; CFlanagan@bradshawcc.com.

Niles Avenue Sewer Improvements Bradshaw Construction Corporation

Bradshaw Construction Corporation has just completed work on a project in the suburbs of NW Atlanta for the Department of Watershed Management to realign an existing 15-in. sewer line. BCC installed four liner plate shafts ranging in size and geology, and 1,857 lf of 18-in. ductile iron sewer pipe by trenchless means in difficult geotechnical conditions that warranted both the use of a Robbins Rockhead Double Shielded TBM and a Herrenknecht MTBM.

The Robbins TBM mined through a 1,000-ft radius curve in a bald rock tunnel spanning a total distance of 713 lf. BCC also completed mining the first MTBM tunnel simultaneously, which spanned a distance of 346 lf in mixed ground conditions. The last tunnel, 701 lf, combined the use of both tunnel boring machines. The MTBM was launched 415 lf one direction into wet silty clay, while the Robbins TBM launched in the opposite direction to receive the MTBM within the rock portion of the drive. The Robbins machine reached the face of the MTBM and was backed up into the shaft, allowing the MTBM to be jacked the remainder of the way. The 18-in. DI pipe was installed, and CJ Geo was utilized for backfill grouting. Construction was completed December 2020. Project members included The City of Atlanta (Owner), Garney Construction (General Contractor), and Bradshaw Construction as the shaft and tunneling subcontractor.

Project Information: Chris Flanagan – Project Manager; CFlanagan@bradshawcc.com.

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.

Mining commenced in September 2016 from a 35-ft diameter shaft that was previously constructed as the retrieval shaft for the Deep Rock Tunnel Connector alignment. After successfully mining the Lower Pogues Run Tunnel, the TBM was backed up and successfully relaunched within the White River Tunnel. The TBM holed through at the White River Tunnel Retrieval Shaft on April 10, 2019, completing close to 41,000 ft of mining. As of December 2020, all adits and deaeration chambers have been drilled and shot, for a total of approximately 2,000 ft of excavation. Additionally, concrete lining operations are ongoing in both tunnels. Based on the terms of a federal consent decree, the White River and Lower Pogues Run Tunnels must be operational by the end of 2021.

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.; 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 10 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 from a 30-ft diameter shaft that was previously constructed as the retrieval shaft for the White River Tunnel alignment. After successfully mining the White River Tunnel, the TBM mined through the shaft and underwent a minor refurbishment. Mining was completed on April 1, 2020. The tunnel terminated approximately 2,400 ft past the retrieval shaft location. The TBM was backed up and parked downstream of the shaft, and the remainder of the shaft was shot down to the invert. The TBM has been retrieved and transported to the site of the Pleasant Run Tunnel launch shaft, where it is undergoing refurbishment before mining the final leg of the DigIndy system. The Fall Creek Tunnel has over 5,200 ft of adits, and adit excavation is ongoing. 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.; 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.

Slurry wall installation for the launch shaft occurred in the Summer 2019. The launch shaft has been excavated to the invert elevation, and the contractor has started excavation of the 500-ft long starter tunnel. The TBM completed mining the Fall Creek Tunnel in April 2020 and was delivered to the Pleasant Run launch shaft site where it is undergoing refurbishment prior to reassembly underground. Mining is anticipated to commence in March 2021. 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.; 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 issued NTP Nov. 8, 2017, and is scheduled to reach Substantial Completion by May 2021 (Final Completion: Spring 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. S-T JV has completed construction of the Drop Shaft DS01 surface structure, shaft, and adit connection to the main tunnel.

Currently, S-T JV is working on concrete lining for the starter tunnel. Construction of the surface structure at Drop Shaft DS02 is ongoing. At Drop Shaft DS04, S-T JV is installing the drop and vent pipes within the excavated shaft, while concurrently backfilling around them. Drill-and-blast excavation of the adits for Drop Shafts DS03 and DS05 is ongoing.

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

Key Project 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.

Shady Grove Sewer Extension Tunnel Bradshaw Construction Corporation

Bradshaw Construction Corporation recently completed construction on a sewer extension project for a new development in Derwood. The 48-in. RCP, 190-lf tunnel was installed behind a Herrenknecht AVN-1200 MTBM underneath Crabbs Branch Way. Tunnel geology consisted of rock with UCS ranging up to 27 ksi. The tunnel passed underneath the highway and sensitive utilities. After tunneling was completed, 16-in. DIP was installed and backfilled. The project members include EYA Developers (Owner) and W.F. Wilson (General Contractor), with Bradshaw Construction Corporation working as tunneling subcontractor. Project Information: Jordan Bradshaw – Project Manager; Jordan.bradshaw@bradshawcc.com.

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

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 is scheduled for Nov. 30, 2021, and final completion of the tunnel and dewatering pump station is scheduled for Sept. 9, 2022.

The project includes 22,800 lf of 19-ft diameter tunnel with 5 drop shafts. The average depth is 120 ft. The project is 88% 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 installed in 15,800 ft of 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).

Key Project Personnel: SAK – Project Manager; Brent Duncan. Project Engineer; Dan Swidrak. Tunnel Engineer; Heath Groom. Project Controls; Tom O’Sullivan. Tunnel Division Safety Manager; Jack Lynch. Safety Manager; Cedric Bransford. General Project Supt.; Terry Beesley. Project Superintendent; Frank Lynch. 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 LLC

This $63.3 million project for the Metropolitan St. Louis Sewer District consists of the construction of approximately 17,800 lf of 11-ft excavated diameter tunnel, and the installation of a 7-ft diameter FRP carrier pipe and fiber optic conduits in the tunnel. NTP was issued March 1, 2017. Estimated completion is early 2023.

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.

As of December 2019, excavation of the launch and retrieval shafts has been completed, and 7,100 ft of the tunnel had been mined. Tunneling work was suspended in December of 2019 following the TBM encountering a karst feature while mining. In July 2020 after additional investigation the contractor constructed a 205-ft deep recovery shaft and began excavating through the karst feature. It is anticipated that the contractor will have completed the excavation through the karst feature by April 2021. Completion of the entire project is currently anticipated to be in early 2023.

Karst was 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 and shaft construction and carrier pipe installation), Goodwin Brothers Construction (intake construction). TBM Manufacturer: Robbins.

Key Project 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, Vice President, Shannon & Wilson, Inc. SAK – PM; KC Hildenbrand. PM Dan Swidrak. General Project Supt.; Terry Beesley. Project Superintendent; Jeff Belt. Tunnel Superintendent; Jackie Bragg. Tunnel Division Safety Manager; Jack Lynch. Safety Manager; Ken Vandergeest.

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 14.5-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. Project will start mobilization of shaft sites in early February 2021.

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.

Key Project 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; Heath Groom. Project Controls; Tom O’Sullivan. Tunnel Division Safety Manager; Jack Lynch. Safety Manager; Cedric Bransford. General Project Supt.; Terry Beesley. Project Superintendent; Shayne Peck.

Maline Creek CSO Storage Facility SAK/Goodwin Joint Venture

This $82.8 million project consists of the construction of a 28-ft finished diameter concrete-lined cavern, approximately 2,700 ft long, and a 40-ft diameter 12.5-million gallon per day submersible pump station. The purpose of the cavern is to store wet weather flows from combined sewers that otherwise would have overflowed to Maline Creek. The stored flow will be pumped from the cavern back to the sewer system and treatment plant when capacity becomes available after the storm. Besides the pump station shaft, which served as the access shaft during cavern mining, there are eight bored shafts associated with drop and vent pipes. The cavern was constructed by drill and blast methods and is located approximately 140 ft below grade in limestone bedrock.

The project achieved substantial completion on Sept. 10, 2020. The storage facility and associated pump station have undergone start-up and demonstration testing.

The project is located close to the floodwall, which provides flood protection to the City of St. Louis. A 6-ft adit from the main cavern crosses beneath the floodwall. Construction of the cavern and adit near and under the floodwall required close coordination with the U.S. Army Corps of Engineers and special monitoring of the floodwall.

Tunnel Designer: Jacobs Engineering Group. Construction Manager: Black & Veatch Corporation. Major Construction Subcontractors: Williams Tunneling (tunnel and shaft construction), XL Contracting (near surface sewers).

Key Project Personnel: Patricia Pride, Project Manager, Metropolitan St. Louis Sewer District; Ray Scherrer, CM Program Manager, Metropolitan St. Louis Sewer District; David Ahlemeyer, Design Project Manager, Jacobs Engineering Group; Andrew Bursey, Lead Tunnel Designer, Jacobs Engineering Group; Colin Sessions, Designer – Lining and Intake Design, Jacobs Engineering Group; Jon Reader, Project Manager, SAK/Goodwin Joint Venture; Doug Wachsnicht, Project Executive, SAK/Goodwin Joint Venture; Kevin Nelson, Construction Manager, Black & Veatch Corporation; John Deeken, Resident Project Representative, Black & Veatch Corporation. Project Coordinator; Loren Goins. Asst. Construction Manager; Spencer Miller. General Project Supt.; Terry Beesley. Project Superintend; Shayne Peck. Tunnel Division Safety Manager; Jack Lynch.

Schoharie Reservoir Low Level Outlet Southland / Renda JV

This is a $142.6 million project for the NYC DEP. NTP was issued June 29, 2015. Estimated date of completion is April 2022.

Both 9.5-ft microtunnels are complete: the 1,225-ft land leg drive and the 950-ft water leg drive with wet retrieval from the bottom of reservoir at a depth of 160 ft. An unplanned extensive rebuild of the machine was required between the two drives due to significant wear of both internal and external parts. Both line and grade were within tolerance for both tunnel drives. Wet retrieval required an adjustment to the original planned operation necessitating field adjustments to the means and methods.

The shaft has been concrete lined to near the top and the wheel mounted roller gate frames installed and dry fit. Work on the concrete gate guides that extend from the bottom of the shaft to the maintenance floor 140 ft above is near complete. Once complete, shoring will be installed and the maintenance and hoist floor cast followed by the remainder of the circular building aboveground. The concrete for electrical enclosure adjacent to the gate shaft is complete and the masons will start the bluestone cladding in the spring.

After retrieval, the adaptor was cut off the Permalok pipe by divers and the 90-degree elbow and intake set and welded onto the tunnel pipe by way of a buttstrap connection. The underwater cofferdam was then filled with tremie concrete to just below the bellmouth and a plug installed so that the tunnel could be dewatered. A 25-ft tall 12-sided inlet screen made of 316 stainless steel was then positioned over the intake with 1 ft below the top of the bellmouth and tremie concrete placed to lock it in place. A hatch at the top will allow for removal of the plug at the end of the project and also allow for installation of the plug in the future for maintenance and inspection. All marine equipment has been removed from the reservoir and demobilized.

After removal of the marine equipment from the reservoir, the temporary sheeting for the marine staging area was removed and stacked rip rap placed along the bank leading up to the East Overlook area. The East Overlook will be a visitor center open to the public for viewing and history of the dam. Footers and walls have been placed for the majority of the retaining walls and the interpretive center. Masonry work will begin shortly along with piers for the pedestrian bridge and additional architectural finishes. Civil work including two bio-retention cells, storm drains and other permanent erosion control have been installed. Bridge erection, sidewalks and paving will follow.

The valve chamber building, a 3-story cast in place building with slabs up to 10-ft thick and walls up to 6-ft thick utilizing colored concrete and an aggressive formliner to match the face of the dam, is more than 70 percent complete with both 78-in. knife gate valves, ultrasonic flow meters and cone valves in place. The embedded stainless steel plates are installed in the hood structure with minor welding remaining before installation of the dissipator baffle plates. 90% of the building concrete has been poured. Once the shell is complete, the remainder of the mechanical and electrical systems will be installed followed by the architectural finishes.

The wing walls used to protect the building from high flows are complete along with the walers, 33 tiebacks and majority of concrete encasement. Most of the concrete used on the project is colored and textured to mimic natural stone.

The RCC berm has been covered with topsoil and seeded. Permanent erosion control features have also been installed in this area as well. The remainder of the stream restoration will be next spring following the end of the Bald Eagle breeding season.

Other Major Parties Affiliated with the Project: DEP AM, Emory Chase; Project Designer (Gannett Fleming/Hazen Sawyer), Everette Knight; Resident Engineer (AECOM), Patrick Hoosier; MTBM Manufacturer, Herrenknecht.

Key Project Personnel: SRJV Project Manager, Chris Davis; Project Engineers, Tim Bray, Joe Janke, Ammar Fallaha, Christy Ellis; Superintendent, Douglass Somers; Safety Manager, Jose Perdomo.

Dairy Branch Tributary Bradshaw Construction Corporation

Bradshaw Construction Corporation has begun construction on sanitary sewer tunnels in Charlotte. The 2,399 ft by 60-in. steel casing tunnel will be installed behind a Herrenknecht AVN-1200 MTBM for a 36-in. PVC sanitary sewer. Subsurface conditions consist of granitic rock ranging from 25 kpsi to 38 kpsi and alluvial deposits. Construction started November 2020. The project members include Charlotte Water (Owner), STV Engineers Inc. (Engineer), B.R.S. Inc. (General Contractor) and Bradshaw Construction performing as tunneling subcontractor.

Project Information: Matthew Webb – Project Manager; mwebb@bradshawcc.com.

Little Sugar Creek Tributary to Central Business District Bradshaw Construction Corporation

Bradshaw Construction Corporation has started construction on one-pass sanitary sewer tunnels in Charlotte. The 3,587 ft by 48-in. reinforced concrete pipe tunnel will be installed behind a Herrenknecht AVN-1200 MTBM. Subsurface conditions consist of granitic rock ranging from 9 kpsi to 30 kpsi and alluvial deposits. Construction began September 2020. The project members include Charlotte Water (Owner), WSP USA (Engineer), Sanders Utility Construction Co. Inc. (General Contractor) and Bradshaw Construction performing as tunneling subcontractor.

Project Information: Matthew Webb – Project Manager; mwebb@bradshawcc.com.

Doan Valley Tunnel Project McNally/Kiewit DVT JV

This is a $142.3 million project that is part of the Northeast Ohio Regional Sewer District’s (NEORSD) Project Clean Lake. NTP was issued July 10, 2017, with Substantial Completion scheduled for November 2021.

The job features two conveyance tunnels (WCT and MLKCT) with an 8.5-ft finished diameter for a total length of 9,400 lf, mined with a 12-ft diameter Robbins Main Beam TBM. The tunnels are being completed in two passes: Rib and lagging as initial support; Precast concrete pipe as final liner. Tunnel depth ranges between 30 and 100 ft below grade.

The main tunnel (DVT) is 18-ft finished diameter for 10,000 lf length, mined with a 20.75-ft dia.

Herrenknecht Single Shield Hard Rock TBM. It is being completed in one pass: universal ring, 5+1 segments (fiber reinforced). Tunnel invert depth is between 50 and 100 ft below grade. The project is intercepting pre-existing brick sewers up to 3ft above the tunnel crown.

There are also seven shafts between 23 and 55 ft diameter; 30 to 100 ft deep.

The geology consists primarily Chagrin Shale bedrock for all three tunnels, except for a short reach at the very end of the WCT drive, in Cleveland Shale. Both Chagrin and Cleveland shales rock masses are characterized by low UCS (up to 2,800), clay-filled bedding joints, weathered interbeds, and tendency for slaking.

Milestones reached to date include:

Designer: McMillen/Jacobs Associates – Wade Trim; Construction Manager (NEORSD): Bob Auber; Construction Supervisor (NEORSD): Karrie Buxton; Major Subcontracts: CSI-Forterra (18’ ID precast concrete segments); Northstar (Concrete Structures); BASF (DVT annular grout and ground conditioning); PIG (cellular grout); Jennmar (steel ribs); Nothern Concrete Pipe (8.5’ ID precast pipes).

Key Project Personnel: Chris Lynagh – Project Manager McNally/Kiewit DVT JV; Joe Teter – General Superintended McNally/Kiewit DVT JV; Collin Schroeder – Shaft/Structures Engineer McNally/Kiewit DVT JV; Adam Hornbeck – Superintendent/Walker McNally/Kiewit DVT JV; Lance Jackson – Project Engineer McNally/Kiewit DVT JV; Brian Negrea – Tunnel Engineer McNally/Kiewit DVT JV; Mark Kaletta – Equipment Superintendent McNally/Kiewit DVT JV; Jeff Acor – Chief Surveyor McNally/Kiewit DVT JV; Matt Szaraz – QHSE Manager McNally/Kiewit DVT JV.

ODOT 209007 USR 35-8.76 Jackson County Turn-Key Tunneling Inc.

This is $1.2 million job for ODOT that was needed when a 15-ft diameter sink hole developed on the North Bound shoulder of US 35 and water was being retained and threatened to flood a 30-acre parcel. ODOT assessed the situation and determined that an unknown 96-in. corrugated metal pipe (CMP) had corroded to the point of failure and collapsed. ODOT immediately installed an emergency bypass pumping operation to lower the water level but they knew that a big rain event would cause substantial flooding.

Turn – Key met with ODOT and determined that a 24-ft diameter liner plate access shaft would be large enough to swallow the existing sink hole and provide a working area for pipe cleanout and relining if necessary. Once the shaft was completed, Turn – Key tunneled out the failed culvert and replaced with 2-flange tunnel liner plate for a total of 60 lf. Turn – Key then cleaned out the remaining 357 lf of the existing CMP and determined that several areas had failed and either needed to be individually repaired or the entire project relined. ODOT requested a price comparison and decided it would be best suited to reline the existing with 72-in. Duromaxx pipe. The pipe is being relined currently, with expected completion by Feb. 14. FK Engineering was involved on the design/engineering.

Project Personnel: Brian Froehlich PE, Project Engineer – Turn-Key Tunneling Inc.; Elliott Baum, Project Coordinator – Turn – Key Tunneling Inc.; Gary Ison, Superintendent – Turn-Key Tunneling Inc.; Zach Schaff PE, Project Engineer – ODOT.

12th Street Pump Station Turn-Key Tunneling Inc.

This is an $851,400 project for the City of Portsmouth that includes the construction of 33 vf of 20-fft diameter liner plate shaft; 85 lf of 60-in. liner plate tunnel; and 248 lf of 42-in. Snap-Tite slipline. Crews are using urethane grout for ground stabilization and LSM for shaft backfill.

The 20-ft diameter access shaft is completed, along with the urethane grouting to fill voids outside of the existing CMP. The tunnel back to the sluice gate has been completed and the Snap-Tite carrier pipe has been installed. Major items have been completed and the project will be completed in short order.

The project is needed due to a failing storm sewer that had collapsed adjacent to an existing Pump Station that caused major surface settlement and the loss of the parking lot to the station. Turn – Key Tunneling was contacted to determine if a trenchless solution could be found to repair the sewer. After examining the project limitations, it was agreed that the best way to complete the repair was to move away from the existing station and install a 20-ft diameter access shaft over top of the failing pipe, hand mine the failed section out and then install a new pipe inside the new tunnel/existing CMP. The access shaft location was unfortunately directly below a section of Norfolk and Southern’s railroad tracks. This track was removed and replaced in order to complete the repair. The 20-ft diameter vertical shaft extended to a depth of 33 ft deep.

Turn – Key tunneled from the shaft back to the pump station, and relined existing pipe from the shaft to a sluice gate approximately 250 ft away located under an Army Corps of Engineers levee. Timeframe for completion was constrained due to the river level rising in winter and the coordination with the railroad. Wood PLC is the engineer.

Project Personnel: Elliot Baum, Project Manager – Turn-Key Tunneling; Gary Ison, Superintendent – Turn-Key Tunneling; Richard Isaac PE, Project Engineer – Wood PLC; Richard Duncan PE, Owners Representative – City of Portsmouth.

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

This is a $21 million job for the Tarrant Regional Water District comprising 2,000 lf of 9-ft, 5-in. excavated diameter tunnel in 10 different tunnels crossing TXDOT roads each with launch and receiving shafts (20 shafts). Depths are shallow under 40 ft through sands and clays using a Boom-in-Shield Tunneling machine. NTP was issued Oct. 19, 2020. Estimated completion is Dec. 23, 2021. The project is approximately 15% complete. Crews are Currently tunneling at one of the 10 crossings.

Owner: Tarrant Regional Water District; Designers: HDR Engineering and BGE Inc.; CM: Caledonia Construction Management; TBM Manufacturer: Custom fabricated machine by Southland Contracting, Inc.

Key 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.

Joes Creek Interceptor Southland Contracting Inc.

The Joes Creek Interceptor is a $15.8 million project for the City of Dallas involving 8,370 lf of 60-in. excavated diameter tunnel that will house 36-in. HOBAS carrier pipe. There are 20 shafts (ranging from 21 to 48 vf in depth). Ground conditions include sand, sand with gravel, sandstone, sandy clay, shaley clay, and shale (Eagle Ford). NTP was issued Jan. 28, 2019. Estimated completion is December 2021.

Crews are using three tunnel methods: 60-in. Herrenknecht Microtunnel Boring Machine (76% of job); 60-in. double-shield, open faced, rigid, steering-shoe guided TBM (designed and fabricated by Southland Holdings) (23% of job); and 54-in. casing by jacking and hand mining (1% of job).

All 21 shafts have been excavated, and 16 of 17 tunnels completed to date, with the 17th drive in process (733 ft of 933 ft completed, averaging 80 ft/shift). Crews are installing carrier pipe and manholes, and backfilling shafts as they go. 19 of 21 shafts are in high-traffic streets of Dallas.

Of note, the contractor successfully completed 1,256 lf 60-in. microtunnel drive within 1/16 in. of centerline through drastically changing soil conditions.

Owner: City of Dallas; Lead Designer: Hazen and Sawyer; CM: City of Dallas; TBM Manufacturer: Southland Contracting, Herrenknecht.

Key Project Personnel: SCI Operations Manager: Kent Vest; SCI Project Manager: Elliott Fuller; SCI Senior Engineer: Fareed Imoro; SCI General Superintendent: Homero Lugo.

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

This is a $206.7 million job for the City of Dallas comprising 26,385 lf of tunnel, 32-ft, 6-in. (30-ft finished diameter) with eight intake shafts (ranging from 120 to 200 vf depth) and six lateral tunnels excavated by roadheader or excavators/breakers. The tunnel is being driven through Austin chalk by a Main Beam Robbins TBM. Estimated completion date is March 4, 2023.

Crews have completed excavation of five shafts and currently excavating two shafts ranging from 22 to 35-ft diameter and 110 to 190 ft deep. Approximately 9,000lf of tunnel excavation has been completed with the Main Beam TBM. Crews are currently converting the TBM diameter from 37 ft, 7 in. to 32 ft, 6 in. within the tunnel. The approximately 17,000 lf of remaining tunnel will be completed with the smaller diameter.

The liner is 15-in. cast-in-place concrete. There are six working sites within the city environment with tunneling under city infrastructure (including state highways, light rail tunnels/surface tracks, rail roads).

Owner: City of Dallas; Lead Designer: HALFF; Tunnel Designer: COWI; CM: Black and Veatch; TBM Manufacturer: Robbins; Subcontractor: Oscar Renda Constructing Inc.

Key Project 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.

Integrated Pipeline Project 108” Pipeline – Trinity River Tunnel IPL Partners

This is a $48.5 million project for the Tarrant Regional Water District comprising 4,400 lf of 15-ft, 7-in. excavated diameter (13-ft, 10-in. finished diameter) with three shafts (ranging from 60 vf to 150 vf in depth) using an open face TBM with hydraulic jacks and concrete segmental lining.

The project is 91% completed. Tunnel excavation has been completed and crews are currently grouting the annulus.

The concrete segments were cast on site using the contractor’s segment forms. Tunneling included a river crossing of approximately 700 ft underneath the Trinity River with 50 ft or less of ground cover. Tunneling was completed at a grade of 6.6% through highly weathered mudstone with various faults. Estimated date of completion is March 8, 2021.

Owner: Tarrant Regional Water District; Lead Designer: Parsons; Tunnel Designer: Parsons/Stiver Engineering; CM: Freese and Nichols Inc. TBM Manufacturer: Custom fabricated machine by Southland Contracting Inc.

Key Project Personnel: IPL Partners Operations Manager: Kent Vest; IPL Partners Project Manager: Jose Jimenez; IPL Partners Project Engineer: Hossein Mirenayat; IPL Partners Superintendents: Otilio Ramos.

Bois D’Arc Treated Water Pipeline Segment E Tunnel Southland Contracting / Oscar Renda Contracting JV (SRJV)

This is a $12.4 million job for the North Texas Municipal Water District consisting of 2,534 lf of 118-in. excavated diameter tunnel. The tunnel consists of 4-flange liner plate and will house 84-in. steel carrier pipe. There are two shafts – Launch shaft: 30-ft clear diameter with 4-flange liner plate and ring beams in overburden; and a receiving shaft: 25-ft, 9in. clear diameter with 4-flange liner plate and ring beams in overburden.

The tunnel will be driven through Austin chalk with a double shielded, open faced, gripper type machine with articulated steering. NTP was issued May 25, 2020. Estimated completion is May 2021.

Tunneling was completed on Jan. 6, 2021. Crews are currently disassembling machine and cleaning the tunnel. Next crews will install welded steel pipe (WSP), grout tunnel/carrier pipe annulus, install vertical pipe, and backfill shafts. An SCI-owned portable batch plant is setup onsite for annular backfill grouting with cellular grout.

Tunneling was completed under the East Fork of Trinity River and BNSF Railroad lines in a remote area.

Owner: North Texas Municipal Water District. Lead Designer: HDR. Tunnel Designer: Stiver Engineering. CM: Freese & Nichols. General Contractor/Program Manager: Garney Construction Inc. TBM Manufacturer: Southland Contracting (Bruce Richardson). Tunnel Contractor: Southland Contracting Inc.

Key Project Personnel: SRJV Operations Manager: Kent Vest; SRJV Project Manager: Elliott Fuller; SRJV Senior Project Engineer: Fareed Imoro; SRJV General Superintendent: Clay Griffith; SRJV Superintendent: Genaro Ramos; SRJV Superintendent: Nick Sambrato.

30- & 33-in. North Kuehler Interceptor Replacement – No. 2 Bradshaw Construction Corporation

Bradshaw Construction Corporation has mobilized to install three tunnels for New Braunfels Utilities as part of the North Kuehler Interceptor Replacement projects. All three will be installed by microtunneling, utilizing a Herrenknecht AVN 800, to pipe jack 43-in. steel casing for 30- and 33-in. fiberglass sewer carrier pipes. Tunnel geology consists of granular and cohesive alluvium in the vicinity of the Comal River, twice crossing UPRR tracks as well as through the Wurstfest Festival Grounds. The project members include the New Braunfels Utilities (Owner), Freese and Nichols, Brierley Associates (Engineers), Pesado Construction (General Contractor) and Bradshaw as the tunnel subcontractor.

Project Information: Ryan Purdue – Project Engineer; rpurdue@bradshawcc.com.

W-6 Upper Segment: HWY 90 to SW Military Drive Sewer Main Project SAK Construction LLC

This $169 million project for the San Antonio Water System (SAWS) was issued NTP on July 13, 2020, and has a completion date of July 13, 2023. It involves 29,000 lf of 60-, 78-, and 104-in. gravity sewer main via tunneling and short segments of open cut, as well as the construction of access shafts for construction and permanent structures with depths ranging from 40 to 140 ft deep, and including the abandonment of existing 48- and 54-in. gravity sewer mains.

As of December 2020, SAK has completed the rebuild of both Lovat TBMs for the project. The first is excavating the tunnel, and the second was to begin excavation in January 2021.

The job requires coordination with Lackland Air Force Base, JBSA-Lackland Medina Training Annex, City of San Antonio, Texas Department of Transportation, and Nelson W. Wolf Municipal Stadium. Work areas are in 100- and 500-year flood plans.

Design: Kimley-Horn & Associates; Tunnel Design: Brierly Associates; Construction Manager: CAS and Black and Veatch; Open Cut & Structures: D Guerra Construction; Tunnel Pipe Backfill: Pacific International Grout; Microtunneling: BRH Garver

Key Project Personnel: PM: Ross Webb; Asst. Project Manager: Loren Goens; Project Engineer: Cody Edwards; Field Engineer: Kenneth Knollmeyer; Project Superintendent: Frank Lynch; Tunnel Division Safety Manager: Jack Lynch; Safety Manager: Haley Stegman.

Dittmar Rosslyn Project Turn – Key Tunneling Inc.

This is a $3.349 million project for Dittmar Building Company that involves: Furnish & install (4) working shafts (A-18-ft diameter, B-15-ft diameter, C-16-ft diameter, D-16-ft diameter); Furnish & install 60-in. diameter tunnel with 36-in. diameter ductile iron carrier pipe & grout backfill (3 Runs: 109, 320, and 34 ft); Manholes (4 ea.) including connections of one 12-in. local sanitary and two 8-in. local sanitary lines via open-cut method; Bypass pumping, dewatering, & design assistance.

Three of the four working shafts have been completed. Tunnels 1-3, including an underground interconnect, have been completed. Tunnel 4 is 60% complete. Pipe and manhole delivery was expected to begin Jan. 18, 2021.

This was the first time Turn – Key tunneled a 320-ft tunnel from both ends at the same time and met in the middle. Interconnect tolerance of 0.25 ft was met well within the design parameters and the liner plates were welded together at the joint. The installation of 4 shafts at various depths was done in live traffic with little to no traffic impacts. Crews excavated a 40-ft shaft next to an existing brick manhole and the only entrance into an apartment complex without impeding or disturbing either to create space for a new manhole and a connection point for a new sanitary system.

Project Personnel: Kyle Woodbury, The Dittmar Company; Brian Froehlich, President: Turn – Key Tunneling Inc.; Chris Allen, Estimator: Turn – Key Tunneling Inc.; Chris Leonard, Project Manager: Turn – Key Tunneling Inc.; James Froehlich, Superintendent: Turn – Key Tunneling Inc.

Ship Canal Water Quality Project The Lane Construction Company

The $254.9 million Ship Canal Water Quality Project (SCWQP) for Seattle Public Utilities (SPU) comprises 13,939 lf of 18-ft, 10-in. ID segmentally lined tunnel using a pressurized face Tunnel Boring Machine (TBM). Tunnel depth ranges from 35 to 85 ft to top of tunnel. The project also includes 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 project is 25% complete (at end of 2020). Crews have mobilized to all five shaft sites, and have completed the slurry wall, excavation, and base slab at the West Shaft site as well as installation of the secant pile walls at the Fremont and Queen Anne sites. Over the next six months, crews will construct the interior walls of the West Shaft in Ballard and prepare to launch the 22-ft diameter Tunnel Boring Machine next summer. Additionally, crews will excavate the Fremont shaft and prepare to launch the 8-ft diameter Microtunnel Boring Machine (MTBM) next summer, and continue shaft construction, pipe installation work, and vault construction at each of the three other sites.

When completed, the tunnel will capture and temporarily store more than 29 million gallons of untreated stormwater and sewage until the treatment plant is ready for it. The tunnel will improve water quality regionally by keeping more than 75 million gallons of polluted stormwater (from rain) and sewage on average each year from flowing into the Lake Washington Ship Canal, Salmon Bay, and Lake Union.

The project is a joint effort between two agencies: Seattle Public Utilities (Lead) and King County Wastewater Treatment Division. Both Agencies are under Consent Decree with the US EPA and DOJ, and the Washington State Department of Ecology to have the SCWQP in service by the end of 2025. The Storage Tunnel is the second of five projects in the SCWQP. There are three subsequent projects to connect the new storage facility to the local sewer systems to complete the SCWQP.

NTP was issued De. 26, 2019. Completion is expected by July 19, 2023.

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

Personnel: Owner: Seattle Public Utilities: Keith Ward – Project Executive; Cynthia Blazina – Construction Manager; Alan Lord – Program Manager; Eleanor Jackson – Design Manager; Stephanie Secord – Project Manager. Construction Management: Jacobs Engineering: Greg Colzani – Tunnel Construction Management Leader; Roger Mitchell – Supervising Resident Engineer. Design: McMillen Jacobs Associates: Jeremy Johnson – Design Manager; Dan Dreyfus – Tunnel Design Lead. Contractor: The Lane Construction Company: Daniele Nebbia – Project Director; Fabrizio Fara – Project Manager; Kevin Murray – Construction Manager; Glen Frank – Technical Manager.

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

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

The project consists of two shafts (18 m OD x 68 m and 10 m OD x 110 m) on either side of the Burrard inlet that are connected by 1,100 m of 5.8 m ID, 6.7 m excavated diameter segmentally lined tunnel that will be constructed with a mix shield TBM. Ground improvement includes a safe haven constructed using ground freezing 400 m into the drive. Three permanent water mains (2 @ 2.438 m, 1 @ 1.524 m) will be installed within the tunnel, up both shafts and into large underground valve chambers atop each shaft.

Geology consists of permeable and variable soft ground containing a high percentage of cobbles and boulders with a transition to weak rock over the final 300 m of the drive. Face pressures of up to 7 bar are anticipated and hyperbaric intervention via saturation diving is planned.

South shaft is now 85 m deep and excavation scheduled to be complete in Q1 2021. TBM successfully launched in September 2020 in short mode and reached the first stop for installing additional trailing gear in late October. Phase 2 TBM launch and the start of ground freezing for the safe haven were both slated for early January 2021.

Personnel: Owner: Metro Vancouver (PM: Allen Mitchell, DPM: Mark Qian); Tunnel Designer: McMillen Jacobs (Andrew McGlenn); Construction Manager: Mott MacDonald (CM: Richard Brydon, DCM: Ian Whitehead); Contractor: Matt Burdick, Andrew Rule, Erica Bailey, Bill Crider; 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).

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

This project for the City of Ottawa is being built by TransitNEXT, a wholly-owned subsidiary of SNC-Lavalin, which is the prime contractor. The estimated date of completion is 2022.

The Dows Lake Tunnel is a critical piece of infrastructure providing a north-south connection along the former Trillium Line. 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, the TransitNEXT team is working with the City of Ottawa and its partners to address several historical challenges through design and construction of the tunnel’s upgrades: Improving the water infiltration management system at expansion joints by performing joint repairs.

Upgrading and providing maintenance of the drainage system including the installation of a new pump system and ensuring the adequacy of the existing drainage system capacity.

Upgrades and modernization of the tunnel ventilation system, trackwork, standpipe system, communication systems, and emergency walkway to align with National Fire Protection Association (NFPA) -130 standards.

Length of tunnel: 578 m in length with 23 reinforced concrete box segments separated by expansion joints Height of tunnel: approximately 6.7 m high from the top of the rail

Width of tunnel: approximately 5.1 m wide

Prior to construction getting underway, 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 design and construction teams are also collaborating on an ongoing basis with the maintenance team to assess and formulate preferred solutions in the virtual space, before construction.

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

This 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). Estimated date of completion is 2025.

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

The Parkway cut-and-cover tunnel construction began in 2020. Before it could begin, traffic was shifted, and underground utilities were relocated. Work is staged to minimize impacts on pedestrians, cyclists, and local traffic.

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.

By the end of 2020, excavation of the Parkway tunnel was already well underway: approximately 30,000 cubic meters or 10% of the total quantity, has been excavated, 60% of the pile drilling has been completed and 15,000 m of piles have been drilled along Byron Avenue.

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 support of excavation (SOE) depending on the ground conditions encountered. Types of SOE include slurry walls, secant pile walls and soldier piling and lagging.

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

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

Ashbridges Bay Treatment Plant Outfall Project Southland | Astaldi Joint Venture

This $300 million project for the City of Toronto was issued NTP in January 2019 with an estimated completion date of January 2024. The project comprises a 16-m diameter shaft, 85 m deep; 3.5 km of 8-m diameter TBM excavated tunnel; 7m ID precast concrete segmental lining; 50 of 1-m diameter risers from tunnel (marine work). The anticipated ground is Georgian Bay shale.

The project is currently 30% complete. Construction activities and milestones include: Shaft excavation complete for tunnel activities; 107-m long starter tunnel excavated; 8-m diameter TBM assembled in starter tunnel along with all backup (expected to commence TBM excavation in January 2021); riser installations ongoing.

50 off-shore risers are to be installed in Lake Ontario and connected to the TBM excavated tunnel from within the precast segmental lining.

Consultant & Designer: Hatch with Jacob & Baird; Major Subcontractors: Keller (Secant Piles), Johnson Brother (Off-shore work included Riser installation).

Key Project Personnel – Contractor: Southland | Astaldi JV; Project Manager (Joe Savage); Deputy Project Manager (Francisco Urrutia); Technical Manager (Khaled El-Kalawi); General Superintendent (Curtis Bahten).

Coxwell Bypass Tunnel Project North Tunnel Constructors ULC

The $378 million Coxwell Bypass Tunnel (CBT) for the City of Toronto is being built by North Tunnel Constructors ULC, a JV comprising Jay Dee Canada, Michels Canada, and C&M McNally Tunnel Constructors. NTP was Aug. 7, 2018, and completion is estimated by March 8, 2024.

The scope of the CBT project includes construction of approximately 10.5 km of 6.3 m finished diameter rock tunnel, five (4@20, 1@22 m diameter) storage shafts that are 50-56 m deep and 11 tunnel connection drop shafts, along with associated deaeration and adit tunnels.

The CBT is anticipated to be excavated entirely through shale bedrock of the Georgian Bay Formation, at approximately 50 m deep. Most of the tunnel alignment runs parallel to a buried bedrock valley. The CBT crosses this valley in two locations with the bedrock cover less than 6 m. The contract required a TBM capable of operation in both open and closed mode due to concerns in a 1.1 km length of tunnel with reduced rock cover above the crown of the tunnel with potential to encounter mixed face conditions with saturated, unconsolidated soils in the crown of the tunnel in this stretch. A dual mode TBM (Open and EPB capable of operating with active pressure of 6 bar) was designed and manufactured by Lovsuns for the excavation of CBT tunnel.

The project is currently 40% complete.

Excavation of 1.1 km of low cover tunnel has been completed. Four out of 5 large shafts have been excavated. Eight out of 11 drop shafts/air shafts have been excavated and lined.

Special/unique Features of the Job: Tunneling with a dual mode TBM through a buried valley, utilization of precast segments with two-component grouting in swelling shale of the Georgian Bay formation, re-use of rock excavated in the tunnel as lakefill for a future WWTP expansion project, significant volume of contaminated and deleterious material in shaft and site work, shaft drilling and site work in crowded, congested and high-profile neighborhoods.

Engineering Design and Construction Management: Black & Veatch Canada in association with R.V. Anderson Associates Limited. Major Subcontractors: GFL Infrastructure Group Inc., York Environmental Solutions LTD., D’Orazio Infrastructure Group. TBM Manufacturer: Lovsuns.

Key Project Personnel: City of Toronto – Manager: Jackie Kennedy. Project Lead: Robert Mayberry. Designer/Construction Management – Lead Tunnel Engineer: David Day; Construction Manager: Daniel Cressman; Resident Engineer: Vireak Hinh. Contractor/North Tunnel Constructors ULC – Project Sponsor: Abdul-Ghani “AG” Mekkaoui; Project Manager: Ehsan Alavi.