Tunnel Updates

CALIFORNIA
Laguna Beach 
Tunnel Stabilization and Sewer Pipeline Replacement Project Phase III 
Drill Tech Drilling & Shoring, Inc. 

Generally this $36.5 million project for the South Coast Water District consisted of the major rehabilitation of 9,738 lf of tunnel in Laguna Beach. The Water District maintains and operates an approximate 2-mile long tunnel that follows the bluffs of Laguna Beach between Three Arch Bay and Aliso Creek in Orange County, CA. 

The tunnel was originally constructed in the 1950s using drill and blast techniques with little support, with most of the existing tunnel either bald headed or timber supported. The tunnel condition was deteriorating and required extensive rehabilitation. 

The overall project was broken up into four individual phases. Drill Tech Drilling & Shoring Inc. (DTDS) was awarded all contract phases of rehabilitation work. Currently, DTDS is finalizing the completion of Phase III, which is the final phase of construction. 

This phase of tunnel work Involved the rehabilitation of 4,938 lf of tunnel, which is essentially new tunnel construction, as the old tunnel with active 24-in. sewer line was encased in reinforced concrete and a new 8-ft x 8-ft straight leg horseshoe shaped tunnel was constructed on top supported by steel sets and fiber-reinforced shotcrete. 

The new tunnel was constructed using an AM50 Roadheader supported by electric rail equipment. Rock encountered was exclusively San Onofre Breccia, which consists of siltstone and sandstone with interbedded gravels, cobbles, and boulder sized rocks. Interbedded rocks were of the Catalina Schist variety. 

After rehabilitation efforts, DTDS installed approximately 10,000 lf reinforced concrete invert and the same length of 24-in. C900 PVC pipe to replace the old pipe. DTDS then re-connected approximately 80 lateral connections, including the installation of several new lateral connections that were drilled from the tunnel to facilitate gravity flow into the new sewer pipe. Additionally, DTDS constructed an underground pump station at one of the adit structures to accommodate several homes that couldn’t convey sewage to the new tunnel via gravity. 

Other major features of work include: the rehabilitation of several adit structure entrances with architectural shotcrete, the realignment and abandonment of several sections of tunnel including backfill using cellular concrete that was pumped to distances up to 6,000 lf, slipline reinforcement of the old pipe using HDPE for potential future contingency purposes; and the DTDS design, procurement and installation of a permanent ventilation system for the final tunnel. 

The entire ~ 2 mile tunnel alignment construction was accessed via 20-ft diameter by 100-ft shaft on the easterly side of South Coast Highway in Laguna Beach. The entirety of the tunnel alignment was underneath 100s of multimillion dollar homes on the coastal bluffs. Extensive geotechnical and environmental monitoring program was used to satisfy community expectations and mitigate potential claims. 

This project was physically complete as of April 2024. DTDS was expecting final project completion approval from the District’s board by the end of September 2024. NTP was April 2020.

Tunnel Designer: Mott MacDonald; Construction Manager: Parsons; Key Project Personnel: Drill Tech Drilling & Shoring, Inc. – Project Manager: Derek McDonald, PE; Superintendent: Efrain Ortiz.

Los Angeles
D Line (Purple Line) Extension Transit Project

The Purple (D Line) Extension Project is a 9-mile long project being built by the Los Angeles County Metropolitan Transportation Authority (Metro) 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. It is being built by Skanska/Traylor/Shea JV under a $1.636 billion contract. 

The $1.37 billion Section 2 project includes 2.6 miles of twin bore tunnel and two new stations and is being built by Tutor Perini/O&G. 

Section 3 is a 2.6-mile extension being built by Frontier-Kemper/Tutor Perini JV under a $410 million contract for tunnel construction. Tutor Perini/O&G Joint Venture was awarded the Section 3 stations contract, which is valued at $1.4 billion and includes the construction of two new stations. 

On April 2, 2024, Metro announced that it has successfully completed all tunneling. This major construction milestone was accomplished safely in one of the densest and most geologically challenging urban corridors in the L.A. region and nation.

Contractors utilized the latest tunnel boring machine (TBM) technology to excavate approximately 40-60 ft per day to help complete tunneling for the project.

During its five years of tunneling, Metro faced and successfully overcame many technical challenges like gassy ground, tar sands and abandoned oil wells. Near the La Brea Tarpits, for example, Metro’s advanced TBMs made their way through tar sands, and used horizontal directional drillings to probe the earth so contractors could identify and remove potential objects before any TBM damage occurred. Metro also safely used the same methods to identify and avoid unmapped and abandoned oil wells underneath Beverly Hills High School.

Morgan Hill
Anderson Dam Tunnel Project
Flatiron West Construction, Inc.

This $46 million project for the Santa Clara Valley Water District comprises 1,600 lf of 18- 24-ft diameter horseshoe tunnel and a 90-ft deep shaft, generally 23 ft in diameter with varying geometry with depth to facilitate future pipe placement (Drill Tech designed this scope as design-build).

The geology included Santa Clara and Franciscan formations in the foothills east of Morgan Hill and US-101. Ground conditions in this area vary significantly due to multiple regional faults. Excavation was done by a mechanical roadheader supported by steel sets and reinforced shotcrete.

NTP was issued in November 2021, with tunnel school start in November 2022. The tunnel portion of project is 100% complete with one very minor soil nail scope remaining.

Tunnel initial liner (shotcrete and steel sets) was constructed on schedule despite significant ground condition changes from bid time, resulting in substantially more initial support than planned, including a 80-ft long row of 35 ea. canopy tubes from the shaft over the Transition Zone (which at its widest point is 40 ft wide with a relatively flat back).

The Transition Zone was also completed with a “two-pass” system, with significant design assist by Drill Tech to again help with the very wide 40-ft section of the tunnel as a “wye” splits off near the shaft. A temporary post was installed in the middle of the Transition Zone during the first pass, and then later removed (and the arch married up with the remaining portion of the arch) during the second pass mining the tunnel “wye.”

Tunnel Designer: AECOM; Construction Manager: COWI, Schnabel Engineering, JCK Underground; General Contractor: Flatiron West Construction, Inc. 

Personnel: Drill Tech Drilling and Shoring, Inc. – Project Manager: Alex Folchi. 

San Jose
VTA’s BART Silicon Valley Phase II Project
Kiewit/Shea/Traylor 

The Bay Area Rapid Transit (BART) Silicon Valley Phase II Extension (BSVII) Project is the second phase of VTA’s BART Silicon Valley Program to expand BART service into Santa Clara County. It is the largest single public infrastructure project ever constructed in Santa Clara County. The BSVII Project will extend the BART System from north San José through downtown San José to Santa Clara and is estimated to carry 54,600 passengers each weekday to destinations throughout the Bay Area by 2040. Completion of the project will finally “ring the bay” with frequent rail service. 

The scope of the BSVII Project includes 5 miles of tunnel, 53.2-ft outside diameter and 48-ft inside diameter, and three underground stations. A fourth station, Santa Clara Station, and the Newhall Yard and Maintenance Facility are located at-grade at the west end of the BSVII extension in Santa Clara.

In November 2023, VTA announced that the TBM has been ordered from Herrenknecht. The $76 million TBM for the project will be the third largest TBM ever built. The largest TBM, Tuen Mun-Chek Lap Kok in Hong Kong, was 57-ft, 10-in., and the SR 99 TBM in Seattle was 57-ft, 3-in. TBM manufacturing is expected to take about 18 months. 

The project will be constructed within a variety of alluvial deposits that extend from the ground surface to depths of 300 ft. The deposits consist of non-sequential, laterally variable, interbedded, and discontinuous fine-grained and coarse-grained soils. Fine-grained soils include silts and clays and coarse-grained soils include sands and gravels.

The tunnel alignment will vary in depth from approximately at grade to 160-ft below the ground surface. The entire tunnel alignment will be below the groundwater table with pressures ranging from 1 up to 4.5 bar.

Kiewit/Shea/Traylor joint venture was awarded the Stage 1 Pre Construction Services contract to complete an innovations phase, programming services, engineering design services, open book cost estimating, and schedule development. Bechtel Infrastructure Corp. was selected to provide construction management services. 

The station platforms will be housed within the bored tunnel at the Diridon, Downtown San José and 28th Street/Little Portugal stations. 

Project Parties: Kiewit Engineering Group – KIE, leads and manages design; Tunnel Designer: Arup; A joint venture of HNTB and WSP are providing program management services for the project and a Mott MacDonald/PGH Wong Engineering Inc. joint venture are providing General Engineering Services. Shannon & Wilson is the Geotechnical Engineer Consultant 

Personnel: Project Director: Mike Colpack; Deputy Project Director: Kari Larsen; Project Construction Manager: Dave Hazen; Underground Construction Manager: Christof Metzger; Tunnel Interior Build Out Manager: Shemek Oginski; TBM Manager: Dick McLane, Pre-Construction Manager: William Searles; Estimating Manager: Tony O’Donnell; Design Director: Eric Halvorson; Deputy Design Manager: Kimball Olsen; Lead Tunnel Engineer, Commercial Manager: Brett Campbell.

COLORADO
Denver
West Gates DIW Pond Expansion
Southland Contracting, Inc. 

This unique project addresses Denver International Airport’s (DEN) most significant environmental risk, the discharge of aircraft deicing fluid to receiving waters. Southland Contracting (SCI) is constructing critically needed DIW infrastructure to allow the airport and their airline partners to continue operating during winter weather in compliance with environmental regulations. The new construction will provide volume for the current DIW storage deficit, and the ongoing 39-gate Concourse Expansion Program. Additionally, this project provides for future Deice Pads Delta Sierra (DS) West, DS East Deice Pads Delta (D), and apron expansion DIW runoff and collection storage. 

The overall purpose of this roughly $75 million project is to replace the existing DIW Pond 002. The tunnel scope of work consists of six bores totaling 5,179 lf. Each drive varies by length and diameter to accommodate the active runway, taxiways, and maintenance roads they cross. 

Additional scopes of work include: 

Four (4) 5.4-million-gallon pond cells (total of 21.6 MG of storage) located on the West Airfield

4,400 lf of 72-in. & 90-in. FRP pipe to interconnect between existing Pond 002 and proposed Pond 002R

Diversion structures with gate valves

Pump Station with 4 pumps

1-million-gallon DIW storage tank

14-in. DIW force main to move collected DIW waters to the WADS Ponds or Lift Station No. 1 sanitary sewer system

Control facilities, along with needed infrastructure

Southland Contracting launched beneath Taxiway Whiskey Alpha (WA) / Bravo 4 (B4) in April 2023. A manned 60-in. diameter, Single Shield Tunnel Boring Machine (TBM) excavated the 1,465 lf run for two-pass installation. This tunnel was supported by a combination of steel casing and liner plate. This 60-in excavation was completed in the Fall of 2023, and all carrier pipe has been installed and grouted. 

While the WA/B4 tunnel was under construction, SCI’s second tunnel crew began setup and excavation for a 43-ft deep launch shaft in May 2023. The 38-ft diameter launch shaft is supported by steel rib and wood lagging for a single-pass installation. The 550 lf drive, northwest of Taxiway Charlie November (CN), was excavated using a manned 96-in. diameter Single Shield TBM. The single-pass installation was completed with direct jacked FRP pipe. A 45-ft diameter common reception shaft was installed and supported with steel beam and wood lagging. The common reception shaft connects waste flow from the 550 lf, single-pass installation, to the downstream 2,051 lf drive crossing beneath Runway 16 Lima / 34 Romeo (16L/34R). The 550-LF excavation was completed in November 2023.

Maverick was mobilized to Runway 16L/34R for a two-pass 2,051 lf drive in December 2023.  Maverick was a manned 132-in. diameter, Single Shield TBM. The 132-in. diameter tunnel will carry one 72-in. DIW drain line, two 32-in. DIW High Concentrate drain lines, one 8-in. Glycol Supply line, two 14-in. conveyance pipes, and four electrical and communication lines. This excavation is supported with steel ribs and channel lagging. The 45-ft diameter common reception shaft is 50-ft deep. Given the shallow depth at the launch location, trench boxes were used for the launch pit. TBM tunnel excavation began in January of 2024 and finished in August 2024.

The three remaining bores have been subcontracted to a local firm, Underground Infrastructure Technology (UIT). These bores range from 30 in. to 48 in. diameter and total 1,113 lf. UIT has completed two of the three bores. The final bore is scheduled for completion in October 2024. 

Status of Project:

Contract Execution: November 30, 2022

Notice to Proceed: March 1, 2023

Estimated Completion: Q1 2025

100% complete – 60-in. TBM excavation under Taxiway WA/B4

100% complete – 96-in. TBM excavation single pass

100% complete – 132-in. TBM excavation under Runway 16L/34R

100% complete – Excavation of all four pond cells

Lead Designer: Burns & McDonnel, Inc.; Tunnel Designer: Lithos Engineering, Inc.; TBM Manufacturer: Southland Contracting, Inc.; Contractor: Southland Contracting, Inc.; Subcontractor: Underground Infrastructure Technology, LLC. (UIT); Contractor Design Engineer: Kilduff Underground Engineering, Inc. 

Southland Personnel: Vice President: John Arciszewski; Project Manager: Maxwell Pauley; Tunnel Superintendent: Genaro Ramos.

DISTRICT OF COLUMBIA
Washington
Potomac River Tunnel
CBNA/Halmar JV

The $819 million contract is the largest ever awarded by the Authority. The 5.5-mile-long tunnel will control combined sewer overflows to the Potomac River, improving water quality in this critical natural resource. This work is part of the larger Clean Rivers Project, a $2.99 billion program to improve the water quality of the Anacostia and Potomac rivers and Rock Creek by increasing the capacity of the sewer system.

A joint venture of CBNA and Halmar was selected based on its lowest price proposal and second highest technical score, therefore providing the best value.

The 18-ft diameter tunnel will run deep underground beneath the Georgetown waterfront, along the edge of the National Mall and East Potomac Park, past Hains Point and connect by gravity to the existing Anacostia River Tunnel. Construction will require two tunnel boring machines. Starting from West Potomac Park, one machine will mine south through mostly soft ground, and another machine will head north to bore through rock.

Work on the project began with a ceremonial groundbreaking on May 21. Completion is expected in early 2030, in accordance with the schedule stipulated in the Consent Decree DC Water signed in 2005 with the U.S. Environmental Protection Agency, the Department of Justice, and the District of Columbia. Once the PRT is operational, it will reduce combined sewer overflows (CSOs) to the Potomac River by 93 percent in an average year of rainfall.

FLORIDA
Cutler Bay,
Cutler Flow Way Phase 2
Bradshaw Construction Corporation

Bradshaw Construction Corporation will soon begin construction on a job for South Florida Management District, situated on an ecologically sensitive worksite. The project consists of twin tunnels, spanning a total of 580 lf, under a Miami Dade County canal with minimal cover. Both tunnels will be mined out of a single 37-ft x 32-ft steel sheeted launch shaft utilizing 63-in. FRP Jacking Pipe behind a Herrenknecht AVN 1200 MTBM. Ground conditions are expected to be sand and limestone, all under the water table. The tunnels are scheduled to be completed in February 2025. Project members include South Florida Management District (Owner), North Star (Design Engineers), Central Civil Construction (General Contractor) and Bradshaw Construction Corporation working as the tunneling subcontractor.

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

INDIANA
Indianapolis
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.

All tunnel, shaft, adit, and deaeration chambers are 100% complete, and the Fall Creek Tunnel is now available for additional storage of CSO overflows from the four DigIndy Tunnel segments that have been previously commissioned.  Surface connections to CSO outfalls along the Fall Creek Tunnel alignment are ongoing. Based on the terms of a federal consent decree, the Fall Creek Tunnel must be operational by the end of 2025.

Personnel – Construction PM: Christian Heinz, P.E.; Inspection PM: Sam Cain, P.E. (AECOM); Owner: Citizens Energy Group – Manager, DigIndy Capital Program: Mike Miller, P.E.; Tunnel Construction Supervisor: John Morgan.

Indianapolis
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 was completed in August 2022. Drop shaft and vent shaft excavation and lining is complete. Adit and deaeration chamber excavation is complete, and crews have commenced lining and buildout. Tunnel concrete lining operations commenced in late April 2023 are approximately 98% complete. Surface connections are ongoing. Based on the terms of a federal consent decree, the Pleasant Run Tunnel must be operational by the end of 2025.

Personnel – Construction PM: Christian Heinz, P.E. ; Inspection PM: Sam Cain, P.E. (AECOM); Owner: Citizens Energy Group – Manager, DigIndy Capital Program: Mike Miller, P.E.; Tunnel Construction Supervisor: John Morgan.

MARYLAND
Baltimore
Frederick Douglass Tunnel

On April 3, Amtrak announced that it has awarded a “Delivery Partner” contract to ADVANCE – a joint venture between major infrastructure firms AECOM and Jacobs. The joint venture’s work will include design oversight, construction management, contract management and other administrative support, among other tasks, on this $6 billion to improve rail traffic through downtown Baltimore. The new tunnel replaces Civil War era tunnels that limited capacity and served as a bottleneck on the heavily travelled Northeast Corridor between New York and Washington, D.C.

The announcement follows soon after Amtrak awarded a CMAR contract to build the new Frederick Douglass Tunnel in February to Kiewit/Shea Joint Venture. And last fall, Amtrak awarded demolition contracts and a CMAR contract for the Program’s “Southern Approach,” which includes a new ADA-accessible West Baltimore MARC Station, replacing multiple bridges, and constructing tracks and other railroad infrastructure.

The Frederick Douglass Tunnel project includes two new high-capacity tunnel tubes, approximately 2 miles in length, designed for electrified Amtrak and MARC passenger trains.

MISSOURI
St. Louis
Lower Meramec Tunnel (11746)
SAK Construction LLC (Affholder)

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 73 % 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 termination shaft, tail tunnel, starter tunnel, and the adit to the Fenton dropshaft. The Contractor completed installation of the upper portion of the concrete lining at the starter shaft. The TBM was assembled and passed on site testing in April 2023. The TBM has mined approximately 32,500 feet to date, which is 91% of the 35,903 ft long tunnel.  The contractor has also hand mined four of the six drop shaft adits.  The TBM is expected to hole through in October 2024, and the carrier pipe is scheduled to be start installation in January 2025. Final completion is anticipated by Nov. 20, 2024.

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.

The Tunnel Designer is WSP as a subconsultant to HDR Engineering, Inc. The Construction Manager for the project is Black & Veatch. Major Subcontractors – Bates Construction, Williams Tunneling, J&J Boring; Hayward Baker; TBM Manufacturer – Robbins.

Personnel: Metropolitan St. Louis Sewer District – Design Project Manager: Jerry Jung; Construction Project Manager: Ray Scherrer. Tunnel Design Engineer: Everett Litton, WSP. Construction Manager: Clay Haynes, Black & Veatch: SAK – Project Manager: Jim Buckley. Project Engineer: Patrick Niemuth. Tunnel Division Safety Manager: Jack Lynch. Safety Manager: Matt Muscarella. General Project Superintendent: Shayne Peck. Project Superintendent: Steffan Peck.

OHIO
Akron
Northside Interceptor Tunnel (NIST)
Drill Tech Drilling & Shoring

Drill Tech Drilling & Shoring, Inc. successfully completed excavation of three separate tunnels on the Northside Interceptor Tunnel Project (NIST) under contract with Granite Construction Company. Drill Tech utilized a new Sandvik roadheader, model number MH 621 to excavate the three tunnels.

The Tunnel Overflow Conduit (TOC) consisted of a tunnel excavated from a launch portal to the Tunnel Diversion Structure (TDS) Shaft. The overall length of tunnel was 370 lf with excavated dimensions of 23.5 ft high by 22.5 ft wide (horseshoe). Tunnel support consisted of rock dowels, wire mesh, and shotcrete.

Once at the TDS Shaft, the roadheader was used to excavate a second TBM assembly chamber tunnel. This tunnel had an overall length of 350 lf with excavated dimensions and tunnel support similar to the TOC.

After completion of the TBM assembly chamber, the roadheader was repositioned within the TDS shaft to excavate a third tunnel identified as Rack 32. Overall length of this tunnel was 140 lf with excavated dimensions of 16 ft high by 14 ft wide. Support included rock dowels, wire mesh, and shotcrete.

NTP for this $6 million work was given on Feb. 19, 2024m with final completion achieved on Sept. 17.

The main project for the City of Akron is part of a CSO program. It comprises 6,660 lf of 16.5 ID segmentally lined rock tunnel. The overall project was award to Granite in 2023 with completion anticipated by July 2027. 

Tunnel & Shaft Designer: AECOM; General Contractor: Granite Construction Company.

Personnel: Drill Tech Drilling & Shoring, Inc. – Project Manager: Brent Duncan, PE; General Superintendent: Mike Belderrain; Project Engineer: Tyler Belderrain & Justin Bayer.

OKLAHOMA
Edmond
Arcadia Lake Water Treatment Plant (ALWTP) Intake and Low Lift Pump Station INT-01 Project
Southland Contracting / Oscar Renda Contracting JV

This $66.4 million project for the Edmond Public Works Authority comprises three wet retrieval type tunnels, which will serve as the intakes for the new City water supply system:

“Upper intake” is 150ft long, 16 ft below lake normal pool elevation 

“Middle intake” is 250ft long, 30 ft below lake normal pool elevation

“Lower intake” is 450 ft long, 40 ft below lake normal pool elevation

The project includes construction of a single shaft, 54-ft ID, 80 ft deep, from which all three tunnels will be launched. Shoring consists of secant piles, 80EA, 1-m diameter.

MTBM entry seals will be cast in 2-ft thick final concrete liner. Entry seals have 72-in. flanges, on which slide gates will be installed once tunneling is complete. Crews are jacking 60-in. Permalok jacking pipe (3/4-in. wall) behind a Herrenknecht AVN 1200. The MTBM includes an upskin kit with subsea recovery can and hard rock cutterhead. Ground conditions were expected to include sandstone, claystone and mudstone in undisturbed earth, and alluvial fill with lakebed. 

Tee screens with airburst system will be installed on end of HOBAS pipe. Five ea 150-hp to 300-hp vertical turbine pumps will sit on elevated slab over shaft, suction tubes (column pipes) will extend to floor of shaft with bowl assemblies 75 ft below pump room floor. The pump station will be encapsulated by precast building.

All three tunnels have been completed and slide gates installed. Ongoing are installation of all mechanical equipment including 10-in. air burst line, 3-in. SPD line, and 2-in. chemical lines are taking place in the Wet Well. 

Underground utilities are being installed around the Wet Well in anticipation of pump house foundation construction scheduled for October. Kicking off the foundation construction will be the installation 4 precast structural beams that span the width of the 50-ft shaft diameter in which the pump station will sit upon. The project was currently 57% complete at press time.

This represents the first Lake Tap Wet Retrieval in US using FRP Pipe.

NTP was issued in September 2022 with estimated completion by November 10, 2024. 

Owner: City of Edmond Public Works Authority; Owners’ CM / Engineering Manager: Carollo Engineers; Engineer of Record: Schnabel Engineering; General Contractor: Oscar Renda Contracting; Tunnel Contractor: Southland Contracting, Inc. TBM Manufacturer:  Herrenknecht, Southland Contracting

Personnel: SCI Project Manager: Matt Jackson; SCI Survey Manager: Fareed Imoro; ORC Project Engineer: Silvia Galindo; SRJV Superintendents: Julio Moya.

SOUTH CAROLINA
Columbia
Saluda River Force Main Extension
Bradshaw Construction Corporation

Bradshaw Construction Corporation has started construction on a two-pass sanitary sewer tunnel in Columbia. The 330-ft by 74.5-in. tunnel to allow for the installation of proposed 48-in. sanitary sewer will be installed behind a Robbins Rockhead Double Shielded Tunnel Boring Machine. Construction of a 26-ft liner plate launch shaft and the 330-ft of tunnel has been completed. A portion of the tunnel had to be constructed using drill and split methods due to historic ruins on the surface and a mixed face condition consisting of sand on top of granitic rock. Subsurface conditions consist of granitic rock. Construction began January 2024 and was completed September 2024. The project members include City of Columbia (Owner), Stantec (Engineer) McClam & Associates, Inc. (General Contractor) and Bradshaw Construction performing as tunneling subcontractor.

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

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

This $212.5 million project for the City of Dallas is scheduled for final completion in August 2026. Tunneling has been completed. Key elements of the project include: 

26,385 lf of tunnel

32-ft, 6-in. 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

Austin Chalk

Main Beam TBM

Dewatering Station

To date, crews have completed excavation of 8EA shafts ranging from 22 ft to 35 ft diameter and 110 ft to 190 ft deep. There are a total of eight shafts on project (5 Intake Shafts, 1 Outfall Shaft, 1 Dewatering Station Shaft, and 1 Access Shaft). Crews have completed excavation of six of seven lateral tunnels, with the final lateral tunnel near completion, ranging from 12.5 ft to 25 ft diameter and 50 ft to 500 ft in length. The 26,000 lf of tunnel excavation was completed with a Robbins Main Beam TBM (10,000 lf at 37-ft 7-in. and 16,000 lf at 32-ft, 6-in.).

Approximately 1 mile of 30-ft ID concrete tunnel lining has been completed. CIP lining is ongoing in multiple shafts and laterals.  

On the surface, the dewatering station foundation is complete. Excavation and cement stabilization; concrete pavement, sidewalks, driveways and restoration work continue on major thoroughfares. Final completion is expected by August 2026.

The highlight of the project is the fact the contractor two bored diameters, 32-ft, 6-in. and and 37-ft, 7-in. with the same TBM, They completed a mid-bore diameter change halfway through the tunnel, disassembling the cutterhead into individual pieces, refurbishing them, and then reassembling while removing spacers to reduce the overall diameter.

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 Vice President: John Arciszewski; SMJV Project Manager: Jennifer Matranga; SMJV Safety Manager: Stephen Jones; SMJV General Superintendent/PM: Jose Jimenez; SMJV General Superintendent: Mike Clingon; SMJV Project Engineers: Liany Marino.

VIRGINIA
Alexandria
RiverRenew Tunnel
Traylor-Shea

The RiverRenew Tunnel System Project includes a 2-mile-long, 12-ft-wide tunnel, shafts, and other sewer infrastructure that will help prevent about 130 million gallons of sewage from polluting the Potomac River, Hunting Creek, and Hooffs Run each year. Traylor-Shea was awarded a $454.4 million contract to complete the final design and construct the Tunnel System Project. The Traylor-Shea design-build team consists of Traylor Bros, Inc., and J.F. Shea Co., a joint venture, with support from Jacobs Engineering and Kokosing Construction Co.

The Herrenknecht tunnel boring machine (TBM) began mining on Nov. 1, 2022. AlexRenew reported in March that boring of the Waterfront Tunnel was completed. 

The project also includes the Hoofs Run Interceptor, that will be excavating using a Herrenknecht 76-in. MTBM. In May 2024, crews installed the final sections of the 72-in., 2,500-ft long interceptor. 

Designer: Jacobs Engineering; Construction Manager: Brown & Caldwell, JCK Underground, EPC; Major Subcontractors: Kokosing Industrial, Keller North America; TBM Manufacturer: Herrenknecht AG.

Loudoun County
Milestone Reservoir and Pump Station
Drill Tech Drilling & Shoring

Drill Tech Drilling & Shoring, Inc. has been awarded this unique project which will ultimately allow the owner, Loudoun Water, to temporarily store 1 billion gallons of raw water in an abandoned rock quarry prior to treatment.

Under contract with Clark Construction Group LLC, Drill Tech will excavate and support a large diameter shaft and three separate intake tunnels utilizing drill and blast methods. Excavation of two of the three intake tunnels will start from within the shaft and will terminate into the abandoned quarry. The third tunnel will be excavated from a ledge within the quarry.

The Pump Station Shaft, situated on a parcel at the confluence of Sycolin Creek and Goose Creek, will have an excavated diameter of 34 ft and a depth of 268 ft. Temporary shaft support will consist of rock dowels, steel mesh, and shotcrete.

When shaft excavation reaches El. 136, excavation of Tunnel A will begin. This tunnel will have a length of approximately 730 lf with excavated dimensions of 11 ft tall by 11 ft wide. Temporary tunnel support will consist of rock dowels and steel mesh. A 4 in. thick shotcrete liner will be installed as final support.

After completion of Tunnel A, shaft excavation will resume to El. 65.5 where Tunnel B will begin. This tunnel will have an approximate length of 815 linear feet. Excavated dimensions and tunnel support will be similar to Tunnel A.

Shaft excavation will again resume after completion of Tunnel B to the design depth of El. -25.5. At this point, a 2-ft thick cast in place reinforced concrete liner will be installed within the shaft using slip form methods. Once the liner is installed, a permanent concrete cover will be constructed over the shaft.

A third tunnel, Tunnel C, will be excavated from within the abandoned quarry and will meet the Pump Station Shaft at El. -5.5. Excavated dimensions and tunnel support will again be similar to Tunnels A and B.

Once all excavation is complete, steel pipe will be installed within Tunnel C and up through a 72-in. diameter raise bore shaft which will be excavated adjacent to the Pump Station Shaft.

The job includes: Dewatering and treatment of over 200 million gallons of water from the abandoned quarry; Scaling and rock fall support installed within the quarry above the three tunnel portals; and blasting near sensitive areas including the Washington & Old Dominion Trail.

The project is approximately 15% complete. The bid value of the project is $42,200,000. NTP was issued on March 30, 2024. Estimated completion is January 2026.

Tunnel & Shaft Designer: Arcadis; Construction Manager at Risk: Clark Construction Group, LLC; Geotechnical Instrumentation and Monitoring: Balter Company.

Personnel: Drill Tech Drilling & Shoring, Inc. – Project Executive: Brent Duncan, PE; Project Manager: Kyle White; General Superintendent: Mike Belderrain; Project Engineer: Tyler Belderrain.

Norfolk 
Hampton Roads Bridge-Tunnel
Hampton Roads Connector Partners

With a budget of more than $3.8 billion, the Hampton Roads Bridge-Tunnel (HRBT) Expansion project for the Virginia Department of Transportation is the largest highway construction project in the state’s history. The project involves widening the current four-lane segments along nearly 10 miles of the I-64 corridor in Norfolk and Hampton, with new twin tunnels across the harbor. The expansion will increase capacity, ease major congestion and enhance travel time reliability.

The new tunnels are being bored with a 46-ft diameter variable-density Herrenknecht TBM, 50 ft deeper than the existing tunnels. The project represents only the fourth TBM-bored highway tunnel in the United States (Port of Miami Tunnel, Seattle SR 99 Tunnel and the Parallel Thimble Shoal Tunnel in Virginia are the others), and the second largest TBM used in the country (behind SR 99). 

In addition to new tunnel construction, the project involves replacing/building bridge structures (five bridges to be replaced, 23 to be widened), replacing marine trestles and widening of the roadway from two to three lanes in each direction.

In early 2019, VDOT entered into a P3 design-build contract with Hampton Roads Connector Partners to build the project. Hampton Roads Connector Partners includes Dragados USA (lead contractor) and HDR and Mott MacDonald (lead designers). Also on the joint venture team are Flatiron Constructors, Vinci Construction and Dodin Campenon Bernard.

On April 17, 2024, the TBM reached the halfway point as it broke through the reception wall on North Island. Following the breakthrough, crews began the process of rotating the TBM on a turntable before launching it back toward South Island to complete the tunneling process. Final project completion is expected in 2027.

Norfolk
Parallel Thimble Shoal Tunnel
Dragados USA/Schiavone Construction

The $756 million project entails the construction of a 5,700-ft bored tunnel connecting two southbound trestles of the existing Chesapeake Bay Bridge and Tunnel, a 17.6-mile structure connecting the Norfolk/Virginia Beach areas to Virginia’s eastern shore which first opened to traffic on April 15, 1964. When complete, the new tunnel will carry two lanes of traffic southbound and the existing tunnel will carry two lanes of traffic northbound.

On Feb. 21, 2023, the 43.5-ft diameter TBM began its initial excavation at the tunnel’s headwall, marking the official start of tunneling for the Parallel Thimble Shoal Channel Tunnel. However, after mining 700 ft, the TBM was stopped after encountering an old, buried anchor in the seabed. 

From June 2023 to early December 2023, CTJV developed a plan that included the construction of a safe haven into which the TBM could be driven to allow for a maintenance intervention. This plan involved performing ground improvements of the soil in and around the cutterhead. These improvements were completed by injecting foam grout to seal the area around the cutterhead and between the cutterhead and the safe haven located in front of the TBM. This was all done to prevent any potential cave-ins, or blow-outs, at the cutterhead. By grouting the ground in front of the TBM, CTJV was able to pressurize the excavation chamber and prevent water and sand from flowing into the excavation chamber.

Bulkheads at the front of the TBM, with air-lock chambers, allowed workers to gain access to the cutterhead for inspection, remove any remaining anchor debris and replace any damaged tools. All of this work was completed underground, under the seabed, in front of the TBM.

Upon removal of the anchor pieces, CTJV then performed a full inspection of the cutterhead. It was determined that 389 of the 442 tools on the cutterhead required replacement. A total of 48 wear plates were also replaced.

On April 8, 2024, CTJV began tunneling once again. As of late April, CTJV is averaging a progression of 50+ feet each day and has completed more than 600 feet since resuming tunneling, with a total of more than 1,400 feet of tunnel liner installed, or approximately 25%, since tunneling began in February 2023.

The revised schedule forecasts project completion forecast for May 2027.

Occoquan
Occoquan River Crossing Transmission Main
Drill Tech Drilling & Shoring

Drill Tech Drilling & Shoring, Inc. successfully completed excavation of one large diameter shaft, two small diameter raise bore shafts, and one tunnel on the Occoquan River Crossing Transmission Main project under contract with Garney Construction.

The upper section of large shaft through overburden was excavated to a diameter of 27.5 ft and to a depth of 20 ft below grade. This section of shaft was supported with steel ring beams and wood lagging. Below this, shaft excavation continued through bedrock utilizing drill and blast methods. Excavated diameter was 24 ft with a vertical depth of 75 ft. The lower section of shaft was supported with rock dowels, welded wire mesh, straps, and shotcrete.

A 411-ft tunnel was then excavated beneath the Occoquan River; drill and blast methods were used to excavate this horseshoe-shaped tunnel to dimensions of 12 ft tall by 10 ft wide. Tunnel support consisted of rock dowels, welded wire mesh, and straps.

After completion of tunnel excavation, a 7 ft cutterhead was transported through the tunnel to facilitate excavation of two raise bore shafts on the opposite side of the river.

After completion of all excavations, 2-42-in. steel water pipes were hauled into the tunnel, positioned, and strapped down to the invert. Riser pipe installation was completed by the GC. Shaft and tunnel blasting was performed adjacent to a historic downtown district.

Drill Tech’s $6 million project was issued NTP in February 2023 and final completion was achieved in May 2024.

Owner: Fairfax Water; Tunnel & Shaft Designer: Hazen and Sawyer; General Contractor: Garney Construction; Major Subcontractors: Subterranean Boring, Inc.

Personnel: Drill Tech Drilling & Shoring, Inc. – Project Manager: Brent Duncan, PE; Superintendent: Charlie Majestic; Project Engineer: Kyle White.

Spotsylvania
Harrison Road Water Main Extension Project
Bradshaw Construction Corporation

Bradshaw Construction Corporation has recently begun construction on the Harrison Road Water Main Extension project in Spotsylvania. Bradshaw has installed a 33-ft x 22-ft elliptical launch shaft and is currently setting up microtunneling operations. The 542-ft x 60-in. steel casing tunnel will pass underneath I-95 to allow for installing 24-in. DI water main. The launch pit and tunnel begin in 12ksi gneiss, but after 100 ft the tunnel transitions to silty sand for the remainder of the drive. The MTBM will be recovered out of a 16-ft ID liner plate recovery shaft. The primary anticipated challenge will be navigating the mixed face/mixed reach conditions. The project members include the Spotsylvania County Utilities Department (Owner), RK&K (Engineer), W.C. Spratt, Inc. (GC), and Bradshaw Construction Corporation working as the tunneling subcontractor.  

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

WASHINGTON
Shelton
RM18-1806 NAVFAC Repair Railroad Culverts
Drill Tech Mining & Tunneling, Inc. 

The culverts are 235 and 160 ft in length, and are 20-ft wide by 15-ft high. Ground conditions are alluvium and glacial outwash soils. The culverts were constructed by mechanical excavation with milling attachments and canopy tube pre-support. Ground support included liner plate, steel sets, and shotcrete.

Work is nearing completion on the $11.5 million RM18-1806 Repair Railroad Culverts Project for NAVFAC Northwest. The project involves construction of two 20-ft wide by 15-ft tall fish passage culverts, 235 ft and 160 ft in length, beneath an active section of the Shelton-Bangor-Bremerton Rail Line with limited cover (30 and 50 ft for the respective tunnels) outside of Shelton, WA. 

The goal of the project is to replace existing 48-in. culverts with fish passable structures and improve fish passage in the area without impacting rail operations. Drill Tech Mining & Tunneling, Inc. (DTMT) was selected by Advanced Technology Construction as the design build tunneling subcontractor with a contract value of approximately $11.4M. 

Soft ground tunnel excavation was completed using mechanical methods, with ground conditions consisting of alluvium and glacial outwash type soils. Canopy tubes were installed for pre-excavation support and the tunnel support system consisted of liner plate with internal steel arches on 4-ft centers. The tunneling portion of the project included pre-excavation support (canopy tubes), tunnel excavation and support, contact grouting, tunnel shotcrete, and tunnel invert. 

As of press time the project was 90% complete.

Tunnel Designer: FK Engineering Associates & Drill Tech Mining & Tunneling; General Contractor: Advanced Technology Construction.

Personnel: Drill Tech Drilling & Shoring, Inc. – Project Manager: Ryan Carroll, PE; Superintendent: Mike Conner; Project Engineer: John Joyce.

CANANA
ONTARIO
Ottawa
Stage 2 LRT Project – Confederation Line East and West Extension Project
East-West Connectors (EWC)

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

The Stage 2 O-Train Expansion is a signature project in Canada’s national capital, funded by three levels of government. This project will provide the foundation for the National Capital Region’s growth and evolution through the twenty-first century. Stage 2 will improve transit trip times, reduce transfers and allow more customers to enjoy the capacity, convenience, accessibility and comfort of Ottawa’s O-Train network.

The O-Train West extension will deliver the following key benefits:

15 km of new rail and 11 new stations

Direct rail service to major destinations such as Tunney’s Pasture, Lincoln Fields, Algonquin College, and Bayshore Mall

New O-Train service to the communities of Island Park, Westboro, Laurentian, Woodroffe North, Woodpark, Lincoln Heights, Whitehaven, Queensway Terrace North, Bayshore, Iris, Centrepointe, and Lincoln Heights

The O-Train West extension includes two cut-and-cover tunnels:

The 3-km Parkway Tunnel will travel between Kichi Zìbì and Lincoln Fields stations.

The 270-m Connaught Tunnel will link Lincoln Fields and Queensview stations.

Construction of the Parkway Tunnel began in 2020 and was completed by the end of August 2024. Construction of the Connaught Tunnel began in 2021 and was 98% complete by the end of August 2024. The final section of the Connaught Tunnel will be completed by the end of 2024.

The completed Parkway Tunnel travels through federal lands and a City of Ottawa park (Byron Linear Park) to preserve recreational opportunities and community linkages. Work has begun to enhance the Byron Linear Park.

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

Personnel: Alex Saltarelli, Project Director, East-West Connectors GP.