Nashville Annular Space Grouting
The Job
Nashville’s Central WWTP is undergoing extensive improvements to provide service to a growing population.
The Challenge
As part of an upgrade, 400LF of 66″ pipe needed to be slip lined. Once the carrier pipe was selected, the space around its 57.1″ OD needed to be filled.
The Solution
CJGeo proposed using CJFill-ST at 45lb/cuft for this Nashville annular space grouting project. CJFill-ST is batched onsite directly from bulk cement, eliminating supply chain issues with ready mix.
Because the selected CJFill-ST only weigh 45lb/cuft, buoyancy control of the new carrier is simple. By filling it with water, it won’t float during grouting. This allowed CJGeo to grout the entire annulus in a single lift. Single lift grouting significantly reduces the likelihood of partial fills, fouled injection tubing, or trapped voids.
A CJGeo crew placed the 87CY of CJFill-ST in less than an hour.
BNA Culvert Abandonment
The Job
As part of a Nashville International Airport’s BNA Vision project, several hundred feet of culvert needed to be filled with grout.
The Challenge
Due to long runs with no intermediate access, the engineer specified cellular concrete as the abandonment grout. Access to the site was across an active taxiway, so the fewest deliveries possible was very important.
The Solution
To address the need to limit the number of deliveries, CJGeo performed the culvert abandonment using CJFill-UL . CJFill-UL is batched onsite directly from bulk cement. By using bulk cement onsite, there were no concerns about hot loads of ready mix. A single semi was able to deliver all the raw material for the placement.
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.
Dumfries Pipe Abandonment
The Job
This utility relocation included abandonment grouting as part of a VDOT roadway reconstruction and realignment in Dumfries, Virginia.
The Challenge
1,575LF of pipe, a combination of 54″ & 60″ needed to be completely filled with grout. Due to sequencing, the pipe was underneath new roadway at the time of abandonment, so the fewer the number of access points, the better.
The Solution
CJGeo placed 995CY of CJFill-UL14 to completely fill the pipe run. The material was placed in a single day, from a single access point near the center of the pipe run.
RiverRenew Lightweight Fill
The Job
The City of Alexandria’s RiverRenew project is its largest in history. The project includes installation of new interceptors, and a large CSO/conveyance tunnel.
The Challenge
A pile-supported, concrete-encased interceptor needed to be backfilled. Due to the pile support capacity, the maximum allowable density of the backfill was 90lb/cuft.
The Solution
To bring the average backfill density to 90lb/cuft, CJGeo proposed filling between the SOE & concrete encasement with 30lb/cuft CJFill-High Permeability (HP). CJFill-HP has very high permeability, so reduces buoyancy when saturated when compared to other lightweight fill materials. CJGeo successfully filled between the concrete encasement and SOE with 145CY of CJFill-HP18. The placements was done in a single, 6′ deep lift in less than an hour.
The use of very low density material then allowed the client to backfill on top of the structure with normal unit weight material while maintaining the average 90lb/cuft density through the full depth of the fill column.
Valve Vault Infiltration Grouting
The Job
As part of the Purple Line project in Maryland, a large diameter water line was relocated. The tie-in was done inside a 10′ diameter vault that was about 20′ deep, and done in a liner plate shaft. The vault structure was precast.
The Challenge
The vault structure wasn’t concentric in the shaft. This left little room to pour the closure around the pipe penetrations. One of the penetrations leaked, causing the structure to completely fill with water. Per specifications, it needed to be dry.
The Solution
CJGeo proposed grouting the infiltration points with CJGrout-35NHV61. 35NHV61 is a hydroinsensitive, plural component geotechnical polyurethane, certified for potable water contact.
CJGeo mobilized a three person crew to the site, and was able to stop the various leaks in the structure in a few hours.
8′ CMP Joint Grouting
The Job
A spec warehouse was planned for a vacant piece of land which had 1700LF of 8′ CMP running through it. The pipe was installed when the site was first prepped, approximately 10 years prior to construction. Because the site was vacant, there was no maintenance. Nearly every joint showed signs of soil infiltration, and there were massive sinkholes along the entire alignment.
The Challenge
To avoid having the replace the entire run of pipe, the joints needed to be sealed. There were 80 pipe joints and 12 pipe to structure joints that were affected.
The Solution
CJGeo mobilized a polyurethane grouting crew to the the site. Over the course of a week onsite, the crew sealed all of the joints. As part of the joint sealing, the voids around the pipe were filled with CJGrout 20SDB geotechnical polyurethane. After the grouting work was done, the site contractor backfilled the sinkholes and washouts with soil.
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 30lb/cuft CJFill-UL 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.
66″ Water Main Abandonment
The Job
The Purple Line is a light rail line project in suburban Maryland designed to increase connectivity within Maryland’s suburbs of Washington, DC. The project involves extensive utility relocation to facilitate installation of large embankments and the extensive infrastructure required for a double track rail corridor dropped into the middle of an already exceptionally congested/dense corridor.
The Challenge
As part of the project, a large MSE wall needed to be installed over approximately 3000LF of 66″ PCCP water main. In order to avoid any future maintenance problems under the rail alignment, a new line was installed adjacent to the embankment, and the old line needed to be abandoned.
Due to construction sequencing, the embankment was already in place well before the water line relocation was performed.
The Solution
CJGeo worked with the utility relocation contractor to design a grout mix and grouting program that provided sufficient bearing capacity to eliminate concerns about future stability. The ultimate design for the mix was a 100psi cellular grout. Given that the embankment was already in place, the entire 3000LF stretch had to be grouted from just two access points.
CJGeo used a 200CY/hour dry mix batch plant onsite to generate and pump the cellular concrete up to 1500LF to place the material. 2800CY of material were placed over a period of four days onsite with no disruptions to adjacent construction activities.
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.
