2024 North American Microtunneling Job Log
Below is a look at some of the recently completed and ongoing microtunneling projects across North America from the 2024 North American Microtunneling Industry Review.
The need for improved infrastructure across North America is strong, and getting stronger as existing utility systems age. Public demand for minimally invasive construction techniques is high, while more and more public discussion revolves around the topic of infrastructure investment. At some point, funding needs to be committed to rebuilding our infrastructure, and microtunneling is well-positioned to complete the work, particularly in tight urban areas.
To submit your project to the Microtunneling Job Log, email Jim Rush, editorial consultant for Trenchless Technology magazine, at jrush@benjaminmedia.com.
UNITED STATES
CALIFORNIA
Perris
Perris Valley Pipeline Interstate
215 Crossing
JW Fowler Co.
The microtunnel portion of this $59.5 million project for the Metropolitan Water District of Southern California included 2,862 ft of 120-in. steel casing in drives of 931, 1,334 and 597 ft using a Herrenknecht AVN 2000 D. The soil conditions were mixed face with dense to very dense granular soils and blow counts of 16 to 50+.
This project was the largest diameter microtunnel JW Fowler has ever installed at 123-in. diameter. The District held a contest for local school children to write an essay explaining their choice of a name for the machine. A local third-grader submitted Rachel Carson, widely known as the founder of the modern environmental movement. The student and her classmates were invited to the media event prior to the machine launch where the name was unveiled.
The project is approximately 70 percent complete. It began in February 2023 and is expected to end in January 2025. Parsons is the engineer.
COLORADO
Boulder
Boulder Main Sewer Improvements
BTrenchless
This $12 million project for the City of Boulder comprised two microtunnels bored out of a common launch shaft. Drive lengths were 400 lf and 1,500 lf with 60-in. diameter steel casing and 42-in. Hobas carrier pipe for sanitary sewer. Depth was 30 ft to invert. The tunnels go through siltstone bedrock.
Watertight shafts were needed due to a project requirement that prohibited dewatering along the tunnel alignment. Launch and reception pits were constructed as secant pile shafts – 33-ft clear internal diameter at the launch shaft and 20 ft for the reception shaft.
Construction of secant pile shafts began in January 2024. Microtunneling setup began in May. BTrenchless was expecting completion of the 400 lf tunnel in June with both tunnels projected to be completed by October.
Crews are using an Akkerman SL60 MTBM with a mixed ground DCH, MT875K jack grame and AZ100 guide laser. HDR and GEI are the engineers.
Denver
First Creek Interceptor
BTrenchless
The 1,284-ft tunnel was completed in a single drive using 60-in. Permalok Casing. The MTBM alignment traversed beneath the Green Valley Ranch Golf Club for 1,284 ft, reaching depths between 20 and 32 ft and was 15 ft below the groundwater table. The soil conditions primarily consisted of coarse alluvium with a relative density ranging from very loose to medium dense.
Several additions were made to the microtunneling plan due to the drive length: Intermediate Jacking Stations were installed every 400-ft and an Akkerman AZ-100 Total Guidance system was used to maintain line and grade. The AZ-100 is a self-surveying azimuth-based system designed for long-distance and curved pipe jacking.
The $5.5 million project was started in early October 2023 and completed mid-November 2023. Crews used an Akkerman SL60 MTBM. The owner was the City of Aurora. HDR and GEI were the engineers.
GEORGIA
Social Circle
A. Scott Emmons WRF Phase II
Utility Tunnels Project
Strack Inc.
Strack used the microtunneling method to install a 410-ft long, 86-in. diameter steel casing as part of a project for the A. Scott Emmons Water Reclamation Facility for the Newton County Water and Sewerage Authority. GWES was the design consultant. Legacy Water Group was the design builder.
Strack used an Unclemole Super TCS system procured through Iseki Microtunnelling in the United Kingdom.
Trinity supplied the steel casing. Derrick/Clean Slurry Technologies provided separation equipment. Kilduff Underground Engineering provided engineering support for Strack.
NEBRASKA
Omaha
Copper Creek Interceptor Relocation
Super Excavators Inc.
This $5.5 million project for the City of Omaha involved constructing three tunnel drives, each 526 lf, originating from a single shaft. The pipe diameters were 42, 48 and 66 in. of FRP. The ground conditions encountered during the project were predominantly clay.
The Project was completed June 2024. Crews used an Akkerman SL-36C, SL-51C and SL-60C for microtunneling. The engineer was Benesch.
NORTH CAROLINA
Charlotte
Upper Little Sugar Creek Trunk
Sewer Improvements
Bradshaw Construction Corp.
Bradshaw Construction Corporation has started construction on one pass sanitary sewer tunnels in Charlotte, NC. The 2,272-ft by 72-in. reinforced concrete pipe tunnel will be installed behind a Herrenknecht AVN-1800 MTBM along curved alignments. Subsurface conditions consist of partially weathered rock and alluvial deposits. The second tunnel on the project has been redesigned to incorporate a 10-ft x 10-ft horseshoe drill-and-blast to mitigate exposure to hard granitic rock. Construction began November 2021 and was completed February 2024. The project members include Charlotte Water (Owner), Kimley & Horn (Engineer) Sanders Utility Construction Co., Inc. (General Contractor) and Bradshaw Construction performing as tunneling subcontractor.
Raleigh
West Neuse Interceptor Improvements
Bradshaw Construction Corp.
Bradshaw Construction Corporation has started construction on two pass sanitary sewer tunnels in Raleigh, NC. The 580-ft by 87.5-in. steel casing to allow for the installation of proposed 66-in. sanitary sewer will be installed behind a Herrenknecht AVN-1800 MTBM. Subsurface conditions consist of granitic rock. Construction began March 2023 and finished in March 2024. The project members include Raleigh Water (Owner), Black & Veatch (Engineer) JF Wilkerson Contracting Co. Inc. (General Contractor) and Bradshaw Construction performing as tunneling subcontractor.
OHIO
Columbus
Lower Olentangy Tunnel
Granite Construction
The LOT main tunnel will require construction of approximately 17,000 ft of 12-ft diameter tunnel at an average depth of 50 feet. This portion will be mined with a Herrenknecht tunnel boring machine and constructed of precast concrete segments. There are three main shafts (large manholes and other structures to provide access and tunnel controls) along LOT at Tuttle Park north of Lane Avenue, at Gowdy Field near Third Avenue & Olentangy River Road, and at Vine Street.
A 90-in. diameter microtunnel will also be constructed to relieve the OSIS near Second Avenue. The microtunnel will begin at the 2nd Avenue and Perry Street intersection and flow west into LOT at the Gowdy Field Shaft.
A 36-in. relief sewer will also be constructed to relieve a DSR in Third Avenue into LOT. This DSR is on the Kinnear Subtrunk Sewer which serves the Fifth by Northwest Blueprint area.
The LOT project was bid during the Summer of 2020. Construction began in early 2021 and is expected to be completed in September 2026.
Crews completed 1-mile long South run in November 2023. The TBM was relocated to launch shaft and assembled for re-launch of the 2.5-mile long North run January 2024. Mining was projected to be complete by December 2024.
OREGON
Portland
Bull Run Filtration Pipelines CM/GC
JW Fowler Co.
The microtunnel portion of this $26.5 project for the City of Portland includes a single 467-ft drive of 80-in. concrete pipe. The soil conditions include firm to stiff clay and silt with medium to high stickiness.
The pressure waterline will be installed via single pass C300 pipe, eliminating the need for the typical two pass method. Crews will be using a Herrenknecht AVN1500T MTBM. The contracting team is Bull Run Conveyance Partners, a joint venture of MWH Constructors and JW Fowler Co., with Fowler serving as the microtunneling subcontractor. Jacobs is the engineer.
The project is expected to be complete by October 2025.
PENNSYLVANIA
Harrisburg
Harrisburg International Airport
Cargo Apron Expansion Project
Michels
This $30 million project consisted of twin 550-ft drives to install 60-in. RCP casing, a 35-ft long by 42-ft wide by 18-ft deep jacking shaft adjacent to the Susquehanna River, and a 21-ft long by 42-ft wide by 17-ft deep reception shaft.
Constraints included working only during non-operational airport hours, and a 1-ft clearance between the crown of the tunnel and an electrical duct bank. The was high potential for settlement with only 10 ft of over between the tunnel and the runway.
The owner was the Susquehanna Area Regional Airport Authority (SARAA). The engineer was AECOM. Michels was the microtunneling subcontractor the GC, Kinsley Construction. Viannini was the pipe supplier. Nicholson performed grouting. Kilduff Underground Engineering provided instrumentation and monitoring services.
TEXAS
Houston
Chelford City Diversion Package 2
Pate Garver LP
This project is part of the City of Houston’s consent decree with the EPA and will eliminate two lift stations. This is the third project in the Chelford City Diversion program, the microtunneling on each installed by the Pate Garver team.
Pate Garver is using and Akkerman SL 38 and Akkerman 308 with 21-in. Power Reamer on this project. It includes installation of 5,479 lf of 36-in. Hobas pipe in 15 drives, with the longest at 800ft. Soils include fat clay, sandy clay, and silty sand. Pate Garver is also installing 2,107 lf of 18-in. Logan clay pipe in 12 drives averaging 220 ft through silty sand and fat clay.
The value of the project is approximately $13 million. The City of Houston is the owner. LAN is the engineer.
Houston
Chelford City Diversion Package 3
Pate Garver LP
Pate Garver is installing 799 lf of 36-in. Permalok casing in a single drive in sandy/silty clay, and 5,540 lf of 24-in. Hobas in 19 drives, the longest 400ft, averaging 325 ft through in silt.
A project in the City of Houston’s Consent Decree with the EPA, this will eliminate two lift stations. This is the fourth project in the Chelford City Diversion program, the microtunneling on each installed by the Pate Garver team. At completion, the project will eliminate an existing lift station.
The owner is the City of Houston. The engineer is Parsons. Pate Garver is using an Iseki TCC 500, Akkerman 4800 with 28.5 PCH, and Akkerman SL 38. The project value is approximately $11 million.
The start date was June 2024; with completion expected in September 2025.
Houston
Easthaven WWTP Flow Diversion
Package 1
Pate Garver LP
Pate Garver is installing 6,293 lf of 60-in. Hobas pipe in 12 drives, the longest at 800 ft, through fat clay, sandy clay and silty sand using a Herrenjnecht AVN 1200 AB.
A project in the City of Houston’s Consent Decree with the EPA, this project is the downstream of three projects that eliminate lift stations and divert flow from an existing WWTP. The project requires non-driven water-tight shafts in locations where there is a potential for encountering petroleum-contaminated ground and/or groundwater in proximity to existing houses
The owner is the City of Houston. The engineer is IDS. The approximate value of the project is $19 million. NTP is expected in October 2024. Completion is expect in March 2026.
Houston
Facilities Consolidation: Flow Diversion from Tidwell Timbers Wastewater Treatment Plant to FWSD #23 Wastewater Treatment
HB Trenchless LLC
This $15 million project for the West Harris County Regional Water Authority (WHCRWA) consists of the abandonment of the Tidwell Timbers WWTP, demolition and flow diversion from the existing Tidwell Timbers Lift Station on the south side of Tidwell Road, construction of a new Tidwell Timbers Lift Station, and construction of a new force main and gravity sewer. Work is in progress for the installation of 3,137 ft of Hobas jacking pipe with the Herrenknecht AVN800 MTBM and 4,400 ft with the Akkerman GBM. There are a total of 16 liner plates installed with ground water lowering methods. The soils are predominantly clay and sand, mostly below the water table.
Challenges include control of flowing soils for shaft entrance and exits. Working areas are extremely tight in residential areas necessitating compact equipment set up and traffic management in order to mitigate inconvenience on residents.
The first AVN800 tunnel is underway and three drives have been completed with the Akkerman GBM. Final completion is expected by April 2025.
Houston
LSRR Package II – District 129
and District 237 Lift Station Diversions
Pate Garver LP
This approximately $3 million project for the City of Houston involved the installation of 2,084 lf of 15-in. Logan clay pipe and 436 lf of 12-in. Logan clay pipe using an Akkerman 308 with 15- and 18-in. Power Reamers.
A project in the City’s Consent Decree with the EPA, this project will eliminate two lift stations.
The engineer was IDS. The project was completed in September
Houston
Rehabilitation of JFK LS and
Abandonment & Flow Diversion
of JFK #2 L
Pate Garver LP
This $2.1 million project for the City of Houston involved the installation of 1,390 lf of 15-in. Logan clay pipe in five runs, with the longest at 400 ft. Pate Garver is using an Akkerman 4800 with 18-in. Power Reamer.
A project in the City’s Consent Decree with the EPA, this project eliminated a Lift Station located on the grounds of George Bush Intercontinental Airport (IAH).
The engineer is Arcadis. The prime contractor is Servox, LLC with Pate Garver, LP the microtunnel sub.
The project started January 9, 2024, and was completed April 30, 2024.
Houston
Surface Water Supply Project (SWDP) Segment B1/B2
HB Trenchless LLC
Segment B1 and B2 is total of 10.4 miles of 96-in. of Surface Water Supply Tunnels for West Harris County Regional Water Authority (WHCRWA). For the trenchless sections of this project in addition to using microtunneling methods, HB Trenchless deployed an EPB machine, Lovat, excavator shield and open face shields. The microtunnel sections, valued at ~$53 million, were four crossings using a Herrenknecht AVN2000AB System with an adapted soft ground cutter wheel for installation of 106-in. steel casing.
All four drives were carried out under the water table with two of the drives being a full face of sand and the other two with a mixed face of sand and clay. Some sandstone lenses were encountered leading to the necessity to modify the cutter wheel. Two drives were under busy arterial roads, with another under the UPRR railroad track. The final drive was the most challenging as this was tunneled beneath 10 lanes of traffic on Houston’s busy Beltway 8 Highway with about three times MTBM diameter of cover in a full face of sand.
All four microtunnels were completed in April 2024 with the remaining work expected to be completed later this year. Black & Veatch is the engineer.
Houston
WHCRWA – Segments A1 and A2
HB Trenchless, LLC
Segment A1 and A2 is total of 10.7 miles of 96-in. Surface Water Supply Tunnels. Similar to Project B1/B2, the trenchless sections of this project in addition to using microtunneling methods HB Trenchless will deploy an EPB machine, Lovat, excavator shield and open face Shields. The microtunnel sections, valued at ~$48 million, total four crossings using a Herrenknecht AVN2000AB System installation of 120-in. steel casing.
All four drives will be carried out under the water table with up to 25 ft of water pressure with depths ranging to 50 ft. One drive will be under a Bayou and one other will be under UPRR Railroad track. One the other drives there is a potential for gaseous conditions.
Shafts were under construction as of June and microtunneling was due to commence in July and scheduled to be completed by mid 2025. The remaining part of the work is scheduled to be completed by January 2026
West Harris County Regional Water Authority (WHCRWA) is the owner. AECOM and Brierley are the engineers.
Irving
Cottonwood & Hackberry Creek
Wastewater Interceptor Improvements
Super Excavators Inc.
This $27 million project for the City of Irving involved the construction of nine shafts, with diameters ranging from 18 to 32 ft and an average vertical depth of 27 ft, utilizing rib and lagging. Additionally, the project included the installation of seven tunnel drives, totaling approximately 4,668 lf, with 60-in. FRP. The ground conditions encountered on the project consisted of fat clay with clayey sand and silty sands.
A new milestone has been achieved in North America, setting the record for the longest continuous push using HOBAS pipe across all diameters. (2,090 lf)
The project is expected to be 100% completed by August 2024.
Crews used an Akkerman SL60C for microtunneling. Freese and Nichols was the engineer.
UTAH
Provo
Deer Creek Intake CM/GC
Project – Microtunnel
JW Fowler Co.
The microtunnel portion of this $7.9 million project for the Provo River Water Users Association included a single 800-ft drive of a 72-in. steel pipe from a launch portal through a 235-ft high earth fill dam. The MTBM will be recovered from a saddle located underwater via a barge and divers. The soil conditions included sandstone, quartzite, and limestone.
The rock microtunnel boring machine will be recovered from approximately 90-ft of water using divers and a barge on the surface of the reservoir. The job began in April 2023 and is approximately 50 percent complete. JW Fowler expects to complete the project by December 2024.
The engineer is AE2S. Granite Construction is the general contractor with JW Fowler Co. as the microtunneling subcontractor. Fowler is using a Herrenknecht AVN 1500 for tunneling.
WASHINGTON
Seattle
Ship Canal Water Quality Project
LANE Construction
The $255 million Ship Canal Water Quality Project (SCWQP) Storage Tunnel Contract for Seattle Public Utilities (SPU) is comprised of 13,939 lf of 18-ft, 10-in. ID segmentally lined tunnel using a 21.5-ft diameter pressurized face tunnel boring machine (TBM) with tunnel depths ranging from 35 to 85 ft to top of tunnel, and a conveyance pipe casing under the Ship Canal installed via a curved microtunnel drive, 646 lf and 94-in. diameter. The microtunnel was completed by Northwest Boring using a Herrenknecht MTBM.
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.
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 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. The Storage Tunnel is the second of four projects in the SCWQP. There are two subsequent projects to connect the new storage facility to the local sewer systems to complete the SCWQP.
Tunnel mining is completed. The 21.5-ft diameter TBM completed 13,947 ft of the tunnel drive that began in the Ballard neighborhood and traveled eastward along the north side of the Ship Canal to the Wallingford neighborhood. The 10-ft diameter MTBM also completed its journey from Fremont southward under the Ship Canal toward the Queen Anne neighborhood in March 2023. Crews then installed conveyance pipe and below grade vaults at four sites along the tunnel route.
Work on the tunnel project will continue through 2024. The overall SCWQP facility is expected to be put into service in 2027.
CANADA
BRITISH COLUMBIA
Kamloops
Jacko Lake Microtunnels – Drive 4
The Tunneling Company
This project for the Transmountain Expansion Pipeline comprises 1,173 m of tunneling (2,000 mm ID/2,500 mm OD) with an elevation change of 60 m over the alignment. The tunnel was built using RCJP with Jackcontrol in up to 200 MPa Basalt with transition zones of gravels, clays and sands. The Tunneling Company used a Herrenknecht AVN2000D MTBM.
Drive 4 on the Jacko Lake project is currently the longest microtunnel in Canada at 1,173 m. The tunnel alignment was complex with a continuous horizontal curve combined with 4 vertical curves which combined as 700 m R. The drive had an elevation change of 60 m over the alignment which contained a number of transition zones of hard Basalt rock with boulder laden gravels, clays and sands.
The project was further complicated by significant delays with The Tunneling Company taking over the drive from another microtunneling contractor and significant wildfires in the area. This led to challenges with skin friction control which required mitigation.
The project was completed at the end of December 2023.
