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.


Below is a look at some of the recently completed and ongoing microtunneling projects across North America. To submit your project to the Microtunneling Job Log, email Jim Rush, editor Trenchless Technology, at jrush@benjaminmedia.com.


UNITED STATES


ALABAMA


Jefferson Country


Cahaba Sludge Transfer Force Main

Super Excavators Inc.


Super Excavators was subcontracted to install 135 lf of 60-in. steel casing under John Hawkins Parkway, and 288 lf of 60-in. steel casing under Galleria Boulevard. Ground conditions consist of weathered sandstone and rock fill and are extremely challenging due to the presence of large rock fragments in the fill. Work is to be performed in a heavily congested area presenting very tight site constraints. Anticipated start is fall/winter 2019-2020. CH2M is the engineer for Jefferson County Environmental Services. Crews plan to use an Akkerman SL60 for this $1.5 million project.


CALIFORNIA


Healdsburg


Magnolia Force Main Relocation

Vadnais Trenchless Services


This project consists of a 310 lf microtunnel drive of 48-in. OD Permalok steel casing with three 16-in. fused PVC carrier pipes. Shafts will be between 25 and 30 ft deep and will likely be of watertight, sheet pile construction. The microtunnel will be installed in soils consisting primarily of sand and gravel. The tunnel will be approximately 15 to 18 ft below the groundwater table.


The alignment is in granular material (sand and gravel) below the creek bed, yielding a high frac-out risk and there is limited overhead space due to low, overhead powerlines. Crews will use an Iseki TCC1000. VTS mobilized on Sept. 3, 2019, and was 90% complete at end of September.


RELATED: Vadnais Trenchless Stays Focused on Microtunneling


Mission Viejo


Potable and Recycled Pipeline Replacements at I-5 and Oso Creek

Vadnais Trenchless Services


This project consists of one microtunnel drive totaling 410 lf of 72-in. OD Permalok steel casing. The steel casing will contain 20-in. FPVC potable water main encased in a 30-in. FPVC secondary casing and a 30-in. FPVC recycled water main encased in a 36-in. FPVC secondary casing. This project also contains a pilot tube auger bore totaling 120 lf of 30-in. welded steel casing. The steel casing will contain a 12-in. FPVC potable water line.


Shafts will be between 35 and 22 ft deep and will be water tight, sheet pile construction. The microtunnel and pilot tube auger bore will utilize one common receiving shaft. The common receiving shaft and PTAG jacking shaft is inside the Mission Viejo Country Club, which has taken extensive communication, planning and a joint effort by all stakeholders to maintain play at all times. The 72-in. microtunnel crosses I-5 underneath an overpass in close proximity to existing piles and with limited cover. Coordination with Caltrans has been imperative to keep the project on schedule.


VTS mobilized in September and is scheduled to be completed in June 2020. Crews are using an Iseki TC 1350 for this $6.99 million job.


Mission Viejo


Trampas Canyon Dam Outlet Tunnel

Sukut Construction


Kilduff Underground Engineering (KUE) was retained by the construction manager (Butier Construction) to provide support of an approximate 700-lf, 63-in. diameter microtunnel beneath an earth embankment dam in cemented sands. KUE reviewed contractor submittals, provided engineering support and performed construction oversight in the field. During construction, several issues arose during tunneling that KUE documented and provided guidance on. KUE’s efforts directly resulted in no claims being presented to the owner, Santa Margarita Water District, and the project being completed successfully.


Microtunneling, using an ISEKI Unclemole TCC 1350 ID, traversed the Santiago formation, which involves highly variable unconfined compressive strengths ranging from 20 psi to 4,100 psi. The project broke ground in mid-January 2019 and was completed in early June 2019.


San Jose


Fourth Street 84-in. Interceptor, Phase VI-A

Vadnais Trenchless Services


This $1.29 million project consists of a 354-lf microtunnel drive of 84-in. ID (101.5-in. OD) T-Lock lined RCP. Shafts for the microtunneling will be between 20 and 23 ft deep and will be of watertight, sheet pile construction. The microtunnel will be installed in soils consisting primarily of medium-stiff to stiff clay and some clay with sand. The tunnel will be approximately 10 ft below the groundwater table.


This is a design-build contract (Contractor: Steve P. Rados Inc.; Engineer: Stantec Consulting Services), which is unusual for microtunneling work. This tunnel will be installed beneath US101 approximately 0.5 miles east of San Jose International Airport. The cover beneath the freeway is extremely shallow, requiring variances from Caltrans. VTS is also utilizing a single pass installation to keep as much cover as possible, which is unusual for highway crossing

VTS mobilized on Sept. 3 and was 60% complete at the end of September. Crews are using an MTS 2430 MTBM.


Venice


Venice Dual Force Main

Vadnais Trenchless Services


This $88.89 million project involves the construction of a new 54-in. diameter force main sewer extending approximately 10,392 lf in length, which originates from a newly constructed manifold adjacent to an existing pumping plant. From the manifold the alignment proceeds east, then southeasterly and crosses beneath the Marina Del Rey and Ballona Creek channels, continues traveling south within Pacific Avenue and ends at the Coastal Interceptor/North Outfall Sewer (CIS/NOS) Junction structure.


The majority (~9,450 lf) of the new line will be constructed using microtunneling. Most of the microtunneling will be direct-jacked RCCP and approximately 2,800 lf of 80-in. Permalok casing with RCCP carrier will also be installed. The cut-and-cover construction method will be used for the remaining 900 lf.


Award on the project was made in February 2017 and physical work began in May 2017. The project was 55% complete at the end of September, and is scheduled to be complete by fall 2020. Crews are using an MTS 1500, MTS 1650 and MTS 1850.


Vista


V-1 West Vista Way Sewer Phase 1

Vadnais Trenchless Services


This project consists of two microtunnel drives totaling 675 lf of 42-in. OD Permalok steel casing with 15-in. PVC carrier pipe. Shafts for the microtunneling will be between 32 and 25 ft deep and will be beam and plate. The microtunnel will be installed in the Santiago formation consisting of weakly to moderately cemented sandstone and weakly to moderately indurated siltstone.


The tunnels are being installed from two different jacking pits with a common receiving pit. Both tunnels will be under heavily traveled roads and under high cover with limited work area and overhead powerlines. Work is scheduled to be performed in winter 2019 using an Iseki TCS 900.


Vista


Vista Village Dr. Sewer Improvements

TC Construction Co.


Kilduff Underground Engineering was retained by the construction manager to provide support of an approximate 387-lf, 36-in. diameter microtunnel beneath Interstate 78. KUE reviewed contractor submittals and provided recommendations and construction oversight in the field. The tunnel was advanced through heavily weathered granitic rock and soft alluvium.


Microtunneling was performed with a very limited footprint for staging the operation. Space restrictions resulted in mobilizing the separation plant 300 ft from the launch shaft. The project broke ground in November 2018 and was completed in July 2019. Crews used a Herrenknecht AVN700.


michels


COLORADO


Aurora


Fitzsimons-Peoria Stormwater Outfall

BTrenchless


This project includes a 30-ft diameter launch shaft (for both tunnels) constructed between May 1, 2019, and June 17, 2019; a 320-lf drive of 72-in. microtunnel (built between June 18, 2019, and Sept. 6, 2019) and a 148-lf drive of 48-in. microtunnel built between Sept. 9, 2019 and Oct. 4, 2019. BTrenchless used Akkerman Equipment: SL74 MTBM skinned to 75.5 in. OD for the 72-in. nominal Hobas pipe and an SL51 MTBM using the base skin for a 48-in. nominal Hobas pipe. Both drives used an 875K MT jacking frame.


Ground conditions included fill (consisting of sandy lean clay), Eolian deposits (consisting of loose to medium dense clayey sand and medium stiff to very stiff lean clay with sands), and Residuum – a completely weathered claystone and sandy claystone.


Commerce City


Suncor Commerce City Refinery

Underground Infrastructure Technologies


Kilduff Underground Engineering was retained by the contractor to provide CM support and manage microtunneling operations of an approximate 60-lf, 30-in. diameter MTBM at the Suncor Refinery. The installation passed beneath 54- and 42-in. live sewer lines with minimal cover in sandy gravel with cobbles. Contaminated and hazardous ground pushed this project from an auger bore to a microtunnel in order to reduce the workers’ exposure to the ground. The project was successfully completed over the course of three weeks in November and December 2018 using an Iseki Unclemole TCC 660 upsized to 780 mm OD.


CONNECTICUT


Wethersfield


Goff Brook Overflow Closure

Bradshaw Construction Corp.


Bradshaw is in the process of completing a 60-in. microtunneling/conventional TBM project for 30- and 48-in. FRP sanitary sewer installations. The first tunnel (650 ft) was installed by an Akkerman WM480. The second (420 ft), third (855 ft), fourth (152 ft) and fifth (450 ft) tunnels were completed behind a Herrenknecht AVN 1200. An additional drive of 48-in. RCP was added to the project by change order, and mining was completed this winter for this final crossing. This 510-ft drive was installed on a 1,168-ft radius curve. Ground conditions for microtunneling operations were predominantly siltstone, with occasional decomposed rock and dense alluvium.


ILLINOIS


Village of Oak Lawn


Water Transmission Main Bid Package 6A

Super Excavators Inc.


Super Excavators, working as a sub to general contractor Reliable Contracting, will install three microtunnel runs: the Cal-Sag Channel run (414 lf) will be mined in bedrock, while the Norfolk Southern Railroad crossing (310 lf) and the Tinley Creek crossing (755 lf) will be mined in the overlying soils. Bedrock consists of dolostone, while soils vary from clays, silts, sands and gravels. All three runs will be mined with a 90-in. OD Akkerman SL74 pushed by 88-in. OD Permalok pipe.


The Cal-Sag Channel consisting of bedrock will be mined with a specially made rock disc cutterhead. All three runs will be mined below the water table. CDM Smith is the engineer for the Village of Oak Lawn.


RELATED: Minimal Disturbance: Milestone Project Tests Capabilities of Microtunnelling


INDIANA


Fishers


INDOT Drainage Pipe Installation

Super Excavators Inc.


The City of Fishers is in the process of making improvements to SR 37, north of I-69. At-grade intersections will be redesigned as underpasses to allow for free flow of traffic on SR 37. The purpose of the drainage work is to create two off site drainage outfall storm sewers which will carry roadway drainage to the west of SR 37 to natural surface water bodies. Super Excavators and sister company SX Foundations Inc. are providing a $10 million subcontract to Midwest Mole to construct three secant shafts, and two 54-in. MTBM drives – a 1,970-lf run, and a 2,300-lf curved drive. Additional 1,050 lf and 660 lf microtunneling runs have been added to the contract.


Three 35- to 45-ft deep secant pile shafts were installed for the jacking and receiving of the 54-in. MTBM drives. Soils ranged from gravelly sand to clay with the watertable within 10 ft of the surface. The 1,970 lf and the 2,300 lf runs require only three shafts, reducing the impact to the public along the extremely busy 146th Street.


The $10.2 million job began in March 2019 and is scheduled for completion in February 2020. Crews are using an Akkerman SL60 MTBM for microtunneling.


MASSACHUSETTS


Cambridge


Port – PL6 Stormwater Storage Tank

Skanska Construction/SECA


To relieve excessive flooding in nearby neighborhoods, the Cambridge Department of Public Works constructed new sewers and storm water storage facilities. Many of these sewer lines were founded deep within mixed ground conditions consisting of silty sand and Boston blue clay. Kilduff Underground Engineering (KUE) was retained by the tunnel subcontractor, SECA, to analyze a 70-in. diameter tunnel extending 195 lf to be installed using a RASA 1600 MTBM, within 6 ft of an active subway line. The proposed alignment was accomplished within 10 mm of the proposed centerline which was flanked on both sides by high-rise buildings. KUE provided engineering submittals consisting of axial loading, settlement and disturbance analysis, and provided construction considerations for jacking the composite casing pipe.

Specialized MTBM equipment with reduced weight was used to facilitate tunneling through weight-of-hammer clay. The project was successfully completed over a four-month period beginning in November 2018 and finishing in February 2019


MARYLAND


Baltimore


Camden Street Drain Replacement

Bradshaw Construction Corp.


Bradshaw finished work on a project in a high-profile area of downtown Baltimore as the tunnel contractor working with Clark Construction’s design-build team. An existing storm drain is currently located in the invert of the CSX Transportation Howard Street Tunnel and is the cause of frequent flooding. This project replaces that 48-in. storm with a larger, deeper siphon drain that will eliminate the flooding and eventually allow for CSX to increase the size of the existing tunnel to gain freight capacity through the area. A total of three tunnels were mined out of a 55-ft deep shaft at the intersection of Camden Street and Howard Street, in the shadow of Oriole Park at Camden Yards.


From the 26-ft diameter shaft, three tunnels were completed, all starting at different elevations. The first is the Upper Adit Tunnel, 32 ft of 66-in. liner plate, hand-mined tunnel for a 48-in. FRP storm drain. The Upper Adit connects to the existing storm drain being replaced, bringing those flows back to the Camden Street Shaft.

The second tunnel is 68 ft of 48-in. liner plate, hand-mined tunnel for 18-in. PVC pipe, which will ultimately serve as the drain for the Howard Street Tunnel. A reinforced concrete intake structure was poured into place at the far end of the tunnel, which will ultimately be exposed from inside the CSX Transportation Howard Street Tunnel. The Lower Tunnel consisted of a two-pass microtunnel of 73.5-in. steel casing for a 60-in. FRP storm drain. The tunnel spanned 122 ft under Howard Street which finished at the footing of the Convention Center and will be the siphon that reconnects to the existing storm network. The subsurface conditions consisted of poorly graded sand with silt and gravel, which required extensive grouting prior to tunnel excavation.


MINNESOTA


Minneapolis


10th Avenue WM River Crossing

Bradshaw Construction Corp.


Bradshaw will soon begin construction on a microtunnel under the Mississippi River. The microtunnel will be 896 lf and the jacking pipe will be 60-in. steel casing. Subsurface conditions are expected to be weak sandstone.


NEW JERSEY


Piscataway


Western Transmission Main

SECA


Kilduff Underground Engineering was retained by the contractor to perform pre-con submittals consisting of axial loading, shaft design and ground behavior analysis. The project involved 4.5 miles of ductile iron pipe with an approximate 700 lf section installed via microtunneling. The project will provide critical backup water supply to neighboring counties and ensure resiliency in Middlesex County Utilities Authority’s water distribution system. The trenchless portion of this project broke ground in December 2018 and was completed in February 2019. The project as a whole is expected to be completed by 2020. Crews used a hybrid MTS 700.


New York - Gilboa


NEW YORK


Gilboa


Schoharie Reservoir Low Level Outlet

Southland/Renda JV


The New York City Department of Environmental Protection (DEP) retrieved the MTBM from the waters of Schoharie Reservoir, marking another milestone for the $400 million program to upgrade infrastructure and improve operational flexibility at the northernmost reservoir in the City’s water supply system. The MTBM was carefully lifted on July 10 from approximately 135 ft below the surface of the water. In January the machine finished excavating 2,118 lf of tunnels that will be used to release water downstream of the reservoir into Schoharie Creek.


The 9.5-ft diameter Herrenknecht MTBM began its work in 2017. The tunnel was excavated in two segments, both starting at a 185-ft deep shaft located alongside SR 990V. The first leg stretched 1,188 ft from the shaft to the eastern bank of Schoharie Creek. The second leg measured 930 ft from the shaft to the bottom of Schoharie Reservoir, where the MTBM excavated through the reservoir bottom on Jan. 19. After the winter ice melted, engineers set up a system of barges and lifts to remove the MTBM from the water. The entire tunneling effort was unique – it was one of the largest excavations ever by an MTBM that included a deep-water retrieval of the machine.


NORTH CAROLINA


Durham


Eno River Outfall

Bradshaw Construction Corp.


Bradshaw has completed the tunneling for this project, which consisted of a 260-lf microtunnel of 75.4-in. OD steel casing. Subsurface conditions ranged from silty sand to competent rock.


Greensboro


Young’s Mill Outfall

Bradshaw Construction Corp.


Bradshaw has completed tunnel construction on the Young’s Mill Outfall, which consisted of two microtunnels of 430 ft and 420 ft in length under roadways and an interstate highway. The jacking pipe was 60-in. welded steel casing with 36-in. DIP sewer. Subsurface conditions were expected to be mixed-face and mixed reach from silt to competent rock. The rock turned out to be very hard and abrasive.


Raleigh


Lower Walnut Creek

Bradshaw Construction Corp.


Bradshaw recently completed tunneling on a project in Raleigh consisting of a 460-lf microtunnel with 75.4-in. OD Hobas jacking pipe. Subsurface conditions were primarily silty sand and partially weathered rock.


RELATED: Trenchless Technology’s 2018 Microtunneling Job Log


OHIO


Cleveland


Doan Valley Relief & Consolidation Sewer

Super Excavators Inc.


Super Excavators performed a subcontract to Triad Engineering & Contracting to install Reach 3 of the DVRCS. This drive was approximately 1,132 lf of 72-in. ID reinforced concrete pipe. The contract also included construction of a 24-ft diameter ribs with sheet pile lagging launch shaft at approximately 43 vf (Triad provided receiving shaft). The GBR indicates potential for encountering flowing ground along this portion of the alignment. The majority of the alignment is in glaciolacustrine deposits which consist of silt and silty clays.


This $2.38 million project required the microtunnel run to be installed on a unique double curved alignment. A 199-lf curve on an 800-ft radius was installed coming out of the launch shaft, followed by 570 lf of straight tunnel, then another 297-lf curve on an 800-ft radius. An intermediate jacking station was installed, in case of high jacking loads, but was not utilized.


The job for the Northeast Ohio Regional Sewer District began in October 2018 and was completed in January 2019.


Columbus


Lockbourne Intermodal Subtrunk

Michels


Michels and Hobas Pipe USA recently achieved a major milestone with the successful completion last fall of the longest run of Hobas CCFRPM pipe. Michels used an Akkerman SL82P with face access to complete the record-setting 1,880-lf drive of 78-in. ID (81.9-in OD).


The drive was the sixth of nine total drives for the Lockbourne Intermodal Subtrunk Extension project for the City of Columbus. In total, Michels was to install 10,220 lf of pipe by microtunneling. The tunnel depth is 30 ft below ground at the launch site and ranges to 65 ft deep.


New Albany


Blacklick Creek Trunk Sewer

Ward & Burke


The first microtunnel drive has been successfully completed for the Blacklick Creek Trunk Sewer (BCTS), Aldea Services Inc. reported. The project consists of two curved microtunnel drives with lengths of 1,653 ft and 1,501 ft, one launch shaft, and two receiving pits. The drives are located from 20 ft to 38 ft below ground surface and are being excavated using a Herrenknecht (AVN 1200) slurry MTBM on a grade of 0.30%. The geology is predominantly in rock (Cuyahoga shale) with 5% to 10% of the drive length being in a fine-grained till and coarse-grained till material (glacial soils), below the water table.

Construction began on Feb. 4, 2019, with preparation of work areas, construction of jacking and receiving pits (reinforced concrete caisson shaft method), and installation of settlement monitoring points. Microtunneling construction of the first drive (MH-3 to MH-5) began on March 21, 2019, and was completed successfully on May 1, 2019. The total drive length from pit wall to pit wall was 1,653 ft and the average jacking force experienced was 148 tons (including the head), two inter-jacking stations (IJS) were installed but were not used.

Construction of the final drive (1,501 ft total length) began on May 14, 2019 and will incorporate compound curves with 820 ft and 1,640 ft radii, and a 400-ft straight section. The contractor plans to use a relatively new Herrenknecht technology called an “Anti-roll can” which will prevent rolling of the MTBM and increase production.


Painesville


Painesville Outfall

Ric-Man Construction


Ric-Man Construction Inc. achieved a new U.S. standard for longest microtunneled project by completing the 3,947-ft Painesville Raw Water Intake, according to Herrenknecht AG. Crews used a Herrenknecht AVN1500 to jack 60-in. RCP (10-ft lengths) under Lake Erie.


The drive broke the U.S. record of 3,000 ft of 84-in. pipe set by Kiewit Bilfinger Berger JV in 2008 as part of Portland, Oregon’s East Side CSO program. Terratest set the world record for the Altamira Landfall project in the Gulf of Mexico, which involved a 7,369-ft drive of 10.5-ft diameter pipe.


Tunneling was performed from a 67-ft deep shaft. The tunnel alignment was approximately 25 ft below the bottom of Lake Erie. Ric-Man tunneled through full-face shale and a mixed face of shale and clay.


OKLAHOMA


Byng


Atoka Pipeline

Vadnais Trenchless Services


The Atoka Pipeline Raw Water Transmission Line is a $29 million project for the Oklahoma City Water Utilities Trust. Vadnais’ crossing project involves furnishing and installing approximately 2,920 lf of 84-in. diameter RCP and approximately 2,850 lf of 72-in. diameter RCP by microtunneling with installation of 72- and 60-in. steel carrier pipe for raw water transmission. The slopes on the two 84-in. drives are 8.5% and 7.3% and on the two 72-in. drives are 8.5% and 7.3%. The entire tunnel alignments is below the groundwater table.


This project also consists of two deep jacking shafts of 125 vf and two shallow reception shafts of 18 vf. The two jacking shafts will be constructed by a combination of 34-ft ID secant piles shaft up to 65 vf and liner plate the rest, with an overlap of 6 ft.


Start date is August 21, 2019 and end date is June 3, 2021.


Oklahoma City


Sanitary Sewer Project SC-0950

Vadnais Trenchless Services


This project consists of three microtunnel crossings of 540 lf of 88-in. ID steel casing at the I-35 crossing, approximately 195 lf of 88-in. ID steel casing at the BNSF Rail crossing and approximately 170 lf of 88-in. ID steel casing at the BNSF Rail Bridge crossing. VTS will be installing the steel casing in 40-ft lengths via the slurry microtunneling method. Shafts for the microtunneling will be built by the GC. The geotechnical report and the borings indicate that the tunnel alignment will encounter low density rock. The tunnel alignments are approximately 2 to 4 ft below the groundwater table.

The job is scheduled to start in Q1 2020. Crews will use an MTS 1850 MTBM.


Tulsa


TMUA-W 08-18 Cherokee Waterline

Vadnais Trenchless Services


This project consists of two microtunnel crossings of 537 lf at Bird Creek and 160 lf at Flat Rock Creek using 68-in. OD Permalok steel casing with 48-in. PCCP carrier. Watertight shafts will be built by the GC, likely using sheet piles. The geotechnical report and borings indicate that the tunnel alignment will encounter low density rock.

The $1.6 million job is scheduled to start Q1 2020. Crews will use an MTS 1500.


City of Aurora Fitzsimons-Peoria Project


PENNSYLVANIA


Midland


Midland Water Intake

JRCRUZ Corp.


This job for the Borough of Midland consisted of a single 470-lf drive to install 45.5-in. diameter Permalok steel pipe. Ground conditions were conglomerated rock at the shaft and cobbles/boulders and river deposits when the machine was advanced into the Ohio River for a wet recovery.


The project included a deep sunken caisson shaft that was 115 ft deep and 50 ft below the groundwater table. The microtunnel was required to pass beneath a Norfolk Southern Railway. Water from the tunnel and shaft are pumped via 100-ft long vertical turbine pumps to the Midland Water Treatment Plant. The project began in April 2017 and was completed in June 2019 using a Herrenknecht AVN 800.


TEXAS


Houston


Abandonment and Flow Diversion of Interwood M.U.D. 266, and Vickery Lift Stations

Vadnais Trenchless Services


This $14.9 million project for the City of Houston consists of furnishing and installing approximately 4,700 lf of 30-in. diameter sanitary sewer and approximately 3,700 lf of 42-in. diameter sanitary sewer by trenchless method with associated manholes. It is expected that two separate microtunneling crews will be necessary to meet the construction schedule. There will be eight jacking shafts and eight reception shafts of about 40-ft deep each.


VTS will use an Iseki TCC600 MTBM and an Iseki TCC900 MTBM. Start date is Oct. 11, 2019, and end date is April 2021.


Houston


Western Area Trunk Sewer

Super Excavators Inc.


The work for this $19 million project for the City of Houston Department of Aviation consists of approximately 6,110 lf of 24-in. sanitary sewer, 460 lf of 18-in. sanitary sewer, 130 lf of 8-in. sanitary sewer, 40 lf of 6-in. sanitary sewer, sanitary sewer manholes, associated items and appurtenances. Both open-cut and microtunneling, using an Akkerman SL60, will be utilized. Sewer line installation will cross 20 to 23 ft beneath two runways and five taxiways.


Installation requires a tunneling system that minimizes the occurrence of settlement on the surface of runway/taxiway, and will require a monitoring system that would provide an early detection of pavement settlement during tunneling operation. NTP is expected in early January 2020, with completion in spring 2021.


Liberty


Sanitary Sewer System Improvements Phase 1

Vadnais Trenchless Services


This project consists of 1,177 lf of 30-in. FRP microtunnel over three separate drives and 792 lf of 24-in. FRP over two drives. Shafts were built by the GC using conventional trench shoring boxes and slide rails. The microtunnel was installed in primarily sandy silts and clayey soils with lenses of sand. The tunnel is approximately 12 ft below the groundwater table.


The job was successfully completed on June 19, 2019. Crews used an Iseki TCC500 and Iseki TCC600 MTBM.


Waco


Transfer Lift Station Pkg 1

Vadnais Trenchless Services


This project consists of a single microtunnel drive of 517.65 lf of 84-in. welded steel casing with 66-in. FRP carrier. Shafts were built by the GC using watertight using sheet piles. The geology included fill and alluvial soils overlying the much older, Cretaceous-age bedrock of the Ozan formation. The tunnel was approximately 14 ft below the groundwater table.


This tunnel crosses Business Highway 77 along the shores/deposits of Brazos River. The GDR refers to the river deposits as Brazos River Alluvium or Terrace deposits. The $1.24 million job was successfully completed on Aug. 30, 2019. Tunneling was performed using an Iseki TCC1350.


VIRGINIA


Fredericksburg


Claiborne Run Sewer

Bradshaw Construction Corporation


Bradshaw recently completed microtunneling 190 ft of 60-in. steel casing under CSX tracks in Fredericksburg for a 42-in. DIP gravity sewer. The Stafford County DPU (Owner) contracted Timmons Group (Engineer) and W.C. Spratt Inc. (General Contractor) to construct the project, with Bradshaw being selected as microtunneling subcontractor. The 60-in. MTBM used was an AVN-1200 model developed by Herrenknecht. Tunnel depths ranged from 18 to 35 ft below the surface, with the alignment passing beneath the water table through clayey sands, silty sands and poorly graded sands. The tunnel was completed in December 2018.


Lynchburg


Liberty Univ. Vines Center Arena Tunnel

Bradshaw Construction Corp.


Bradshaw Construction Corp. recently completed installing one 72-in. FRP tunnel by microtunneling in Lynchburg, Virginia. The 250-ft tunnel was installed behind a Herrenknecht AVN-1500 underneath the Liberty University campus. Ground conditions consisted of mixed-face/mixed-reach rock transitioning to sandy clay. Weathered/fractured rock overlaid massive schist for the first 150 ft of tunneling, and rock gave way to sandy clay for the remaining 100 ft. The project was performed for CMA Associates (Owner) and Faulconer Construction Co. (General Contractor).


Norfolk


I-264 Storm Sewer Tunnels

Bradshaw Construction Corp.


Bradshaw completed installing two 60-in. RCP tunnels by microtunneling. The two tunnels (270 and 110 ft) were installed behind a Herrenknecht AVN-1500 underneath I-64, HRT tracks and Curlew Drive. Ground conditions consisted of sand, clay and obstruction-laden fill, with minimal ground cover. The project was performed for VDOT (Owner) and Tutor Perini Corp. (GC).


Richmond


Western Area Trunk Sewer

Bradshaw Construction Corporation


Bradshaw completed microtunneling 530 ft of 60-in. steel casing under I-64 for a 30-in. DIP gravity sewer. Henrico County (Owner) contracted AECOM (Engineer) and Gaston Brothers Utilities (GC) to construct the project, with Bradshaw selected as microtunneling subcontractor. The 60-in. MTBM used was a Herrenknecht AVN-1200. Depths ranged from 12 to 32 ft below the surface, with the alignment passing beneath the water table through a full face of sandstone, transitioning to clayey sand and gravel. The tunnel and pipe installation was completed in October 2018.


Virginia Beach


PRS Reliability Upgrades – Providence Rd.

Bradshaw Construction Corp.


Bradshaw will soon begin work on a 182-ft tunnel in Virginia Beach for a 42-in. FRP sewer installation. The 60-in. Permalok steel casing tunnel will be installed behind a Herrenknect AVN-1200. Ground conditions are expected to be poorly graded sand beneath the water table.


WISCONSIN


Waukesha


Greenmeadow Sanitary Interceptor Sewer

Super Excavators Inc.


The $18.4 million Greenmeadow project was developed by the City of Waukesha to provide reliable wastewater collection and conveyance to the area, and meet future demand requirements. The project includes the extension of an interceptor system from the Greenmeadow Pump Station to the Treatment Plant south of Fox River. Total scope includes construction of approximately 2,500 lf of 60-in. RCP (76-in. bore) with a 36-in. Hobas carrier pipe and annular space grouted. The tunnel will be installed in bedrock in two drives.


The job requires installation of two secant pile shafts in bedrock to 35 vf, with drill-and-blast excavation for an additional 30 vf for approximately 65 vf total, and one liner plate shaft in bedrock with drill-and-blast for deep excavation. The project also includes 6,700 lf of sanitary sewer interceptor by deep open-cut construction; 800 lf of 16- and 18-in. diameter double barrel siphon by HDD; 29 sanitary sewer manholes; 24 sanitary lateral replacements; two siphon structures; 5,000 lf of storm sewers; seven storm sewer manholes; five storm sewer catch basins; and 16,000 sq yd asphalt roadway rehabilitation.


The entirety of the tunneling for this project occurs in deep bedrock. The alignment includes one 1,900-ft radius curve. Tunneling was completed with an Akkerman SL74 with a rock disc cutterhead. Tunnel line and grade was maintained via the Akkerman AZ100 Total Guidance System. Tunneling passes below multiple public properties, and multiple existing utilities. Open-cut portions are also deep, at depths greater than 30 ft.


The project began in July 2018 and is currently at 85% completion.


RELATED: Tualatin River Project Extends the Capabilities of Microtunneling


South Surrey Interceptor Johnston Road sectionCANADA


BRITISH COLUMBIA


Vancouver


South Surrey Interceptor

Ward & Burke


The South Surrey Interceptor Johnston Road Section is a twinning needed to enhance capacity and environmental protection. Phase 2 of the section began in June 2018 and consists of approximately 800 m of 3,050-mm ID (3,600-mm OD) reinforced concrete gravity sewer beneath business parks and city streets, in bouldery ground and near several utilities.


Phase 2 was divided into four drives: 370 m, 110 m, 40 m and 285 m. Curved sections were in drives one and four. Crews used an upsized Herrenknecht AVN2500D 3.68-m diameter MTBM – the largest machine used to date in North America. The jacking pipe was designed by W&B and manufactured by Langley Concrete Group.


ONTARIO


Mississauga


Dixie Road and QEW Crossing

CRS Tunnelling Inc.


This project consisted of two drives (one curved): 410 m southbound along Dixie Road and 228 m northbound under the QEW. The geology consisted primarily of shale within interbedded limestone, as well as some running sand found near the retrieval shaft on Dixie Road. Production was 6 pipes/shift.


This was the first project where concrete pressure pipe (CPP) was used as the “jacked tunnel pipe” and the joints were to be tested to 50 psi. CRS constructed three shafts. The launch shaft was built of steel ribs and wood lagging (in the overburden) and rock bolts and wire mesh in the rock. One retrieval shaft was also constructed of steel ribs and wood lagging/rock bolts and wire mesh, while the other was built using gasketed steel liner plate. The $6 million project was completed in August 2018.



Jim Rush is editor of Trenchless Technology magazine.



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