Parsippany Annular Space Grouting
The Job
This microtunneled installation of 48″ sanitary line under an interstate had two tunnels. Each was 60″ diameter, one was 725LF, the other 530LF. They shared a shaft.
The Challenge
The owner specified a grouted annular space for the tunnels. The long pumping distance and relatively tight annulus drove the need for a highly mobile, lightweight grout.
The Solution
CJGeo placed 270CY of CJFill-ST36 (36ksf unconfined compressive strength) cellular grout to fill the annulus on both tunnels. Because the shared shaft wasn’t easily accessible, grouting was performed from each end towards the shared shaft over two back to back days.
Niles Avenue Annular Space Grouting
The Job
Atlanta Watershed Management’s Niles Avenue Sewer Improvements project involved approximately 2500LF of microtunneling to install a new 18″ sewer main.
The Challenge
A 72″ microtunnel was chosen, which required approximately 1200CY of annular space grouting. Operations were challenged by the pandemic hitting in the middle of the project.
The Solution
CJGeo proposed a 30lb/cuft cellular grout for the annular space grout. This allowed the contractor to avoid mechanical buoyancy control during grouting operations during single lift grouting.
Over two mobilizations, CJGeo generated the cellular grout onsite and placed it via shafts which were up to 40 feet deep.
Garden State Parkway grouting
The Job
As part of ongoing large diameter culvert rehabilitations and replacements, four new bored stormwater crossings and the original culvert they replaced needed to be grouted. The tunnels ranged from 120″ down to 74″, for a total of 312CY, and the abandonment required 405CY.
The Challenge
Grout needed to meet the minimum strength requirements of the owner, and ideally needed to be light enough to facilitate single lift annular space grouting.
The Solution
CJGeo’s preconstruction team worked with the general contractor to design a grouting program which facilitated single lift abandonment of the original culvert, and single lift grouting of the four various annular space runs. CJGeo utilized onsite dry batching to generate 30lb/cuft CJFill cellular concrete.
Union County Annular Space Grouting
The Job
Due to a rapidly increasing population, Union County, North Carolina installed a new raw water intake, which required a nearly 11 mile long raw water line to supply a water treatment plant.
The Challenge
While there were dozens of open cut road crossings along the alignment, 17 crossings were bored, and require annular space grouting per NCDOT requirements. Given the length of the project, there weren’t any ready mix providers who could cover the entire project.
The Solution
CJGeo has multiple NCDOT approved mix designs, CJGeo was able to source material from two different ready mix providers, and grout the annular space on each crossing per NCDOT requirements.
Neuse River Annular Grouting
The Job
The City of Raleigh’s Neuse River East Parallel Interceptor project involves the installation of miles of large diameter gravity sewer. Two road crossings required 120″ tunnels for installation of the 96″ HOBAS pipe.
The Challenge
While neither tunnel was very long, due to the 10′ diameter tunnels, grouting needed to be performed in two lifts. This allowed buoyancy control of the HOBAS carrier pipes to be maintained with partial water filling, and eliminated the need to perform hold down blocking during the carrier pipe installation.
The Solution
CJGeo proposed an NCDOT approved cellular grout mix due to passage through an NCDOT right of way, and then grouted the two tunnels each in two lifts. Fill was confirmed with uniform grout vented out the 12 o’clock vent position at the far end of each tunnel.
Dairy Branch Annular Space Grouting
The Job
Charlotte Water’s Dairy Branch Tributary Sewer project is an approximately $30mm capacity improvement project to address increased density.
The Challenge
As part of the project, a 430LF tunnel ranging from 58″ bore to a 4×4 arch was mined. The carrier pipe was 36″ ductile iron, and required annular space grouting using a mix which wouldn’t float the carrier pipe, and would be able to entirely fill the tunnel at low pressure.
The Solution
CJGeo proposed an NCDOT approved cellular grout mix due to passage through an NCDOT right of way, and then placed the 275CY of grout in a single lift over two hours at approximately 5psi of placement pressure.
Bay Park Annular Space Grouting
The Job
The Bay Park Conveyance Project is using a combination of microtunneling and slip-lining to redirect treated effluent discharge from Western Bay to an existing ocean outfall several miles away.
The Challenge
Approximately 7 miles of the discharge pipe is being sliplined into an existing 72″ riveted iron pipe running underneath the Sunset Highway. Access pits are between 700LF & 3000LF apart, requiring annular space grouting placements ranging from 200CY to 850CY.
Due to maintenance of traffic concerns, all grouting must be performed at night, and there is nowhere to stage materials onsite.
The Solution
Working with the design and construction teams, CJGeo designed a 30lb/cuft, 150psi at 28 day compressive strength cellular grout for the annular space grouting. By using dry batch mixing onsite, CJGeo is able to achieve the compressive strength required, and place the distances required in the very short nightly placement windows.
To address material logistics, each night’s cement consumption is staged locally during the day, and then shuttled in to each placement location during the pours.
SW Florida Annular Space Grouting
The Job
City of Fort Myers’s South AWWTF Reclaimed Water Transmission Main.
The Challenge
Two 52″ tunnels with 32″ DIP carriers requiring annular space grouting. Tunnel 1 was 170LF, Tunnel 2 was 607LF. The
The Solution
CJGeo grouted both tunnels utilizing cellular grout with 250psi at 28 day compressive strength.
Brentwood Annular Space Grouting
The Job
As part of large water main installation, a 970′ tunnel, ranging from 60 to 78″ in diameter was mined through a small mountain. A 42″ DIP carrier pipe was then installed by the tunneling contractor.
The Challenge
The annular space needed to be filled with grout to ensure long term stability of the carrier pipe, and of the surrounding ground in an area where the tunnel was hand mined through soil with rib and lagging.
The Solution
CJGeo proposed and installed 25lb/cuft cellular grout for the annular space grouting. By generating material onsite directly from bulk cement, using a dry batch plant, the 425CY annular space was filled in fewer than five hours.
UNO Annular Space Grouting
The Job
As part of a sewer upgrade, three tunnels were mined between four shafts, in Athens, Georgia. Tunnel lengths ranged from 116LF of 700LF, with diameters between 58.5″ ID to 9×9 arch segments.
The Challenge
In order to keep the carrier pipe from floating during grouting, the maximum allowable grout density was 70lb/cuft, and the minimum compressive strength was 200psi. Material had to be highly mobile, to facilitate placement through the 700LF of tunnel.
The Solution
CJGeo proposed 38lb/cuft cellular grout to the tunneling contractor. Over a period of three days, CJGeo batched and placed 1320CY of cellular grout. Batching was performed utilizing an onsite dry mix plant, which was fed directly by bulk cement trailers, minimizing the required laydown area on a very tight site.
Because of the very low grout density, the carrier pipe only needed to be braced by filling it partially with water.
