Fort Lauderdale Permeation Grouting
The Job
This Fort Lauderdale permeation grouting project is located next to Port Everglades. Port Everglades is a crucial piece of Florida’s infrastructure, with annual economic impact exceeding $30 billion dollars per year. The tunnel, which is being mined with a 72″ MTBM, crosses under Eisenhower Boulevard from the George T Lohmeyer Wastewater Treatment Plant towards the Broward County Convention Center.
The tunnel is more than 20′ below grade, below the water table, in limestone with pockets of silty sand.
The Challenge
On this project, the microtunneling contractor had two tunnel crossings. On the first, they elected to not pre-grout their break in & break outs through the SOE. This resulted in a significant water and soil inflow event during the first break in. This crossing, under the entrance to the cruise port and between two other pieces of critical infrastructure, would not tolerate any surface disturbances associated with a flooding event.
The contractor reached out to CJGeo about stabilizing the launch & retrieval shafts to ensure stability during the launch & retrieval processes, by performing permeation grouting.
The Solution
CJGeo proposed permeation grouting of the limestone with an acrylic grout to ensure stability of the launch & retrieval shafts. Permeation grouting with acrylic grout ensures uniform permeation, and displacement of groundwater. It also ensures that the soils are sufficiently bound together to not fail while cutting the launch & retrieval holes in the sheet pile.
CJGeo installed the sacrificial tubing for this installation from the shaft. Occasionally, sonic drilling is useful for pre-grouting, but in this case, it was more economical and less disruptive to go through the shaft walls.
CJGeo performed the permeation grouting work in a single shift at each shaft.
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T Wall Lightweight Backfill
The Job
This T wall lightweight backfill project is located in Boston, Massachusetts. The bridge is located on the Lowell Line, within the MBTA‘s Commuter Rail Maintenance Facility.
The Challenge
CJGeo has been involved in this alternative delivery project since 2020, helping to optimize the use of CJFill-Ultra Lightweight fill to facilitate constructing a new embankment over underlying compressible soils.
In this specific location on the project, curved T walls were installed along the curved alignment (different radius) of the existing embankment. A sheet pile SOE retains the existing embankment. Due to highly irregular spaces, limited access, lightweight aggregate, such as foamed glass, would be exceptionally difficult to install and ensure adequate compaction.
The Solution
CJGeo proposed 26lb/cuft CJFill-Ultra Lightweight as the optimal material for the T wall lightweight backfill. The lowest 4′ is CJFill-High Permeability. Because CJFill is a self consolidating fill, there’s no compaction required. This practically eliminates chances of backfill consolidation. On a curved, relatively high speed commuter rail alignment, settlement could be quite risky if it were to occur.
For the first phase, CJGeo mobilized a single dry batch cellular grout plant. The work took a total of five days.
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TBM Intervention Permeation Grouting
The Job
This TBM intervention permeation grouting project is located in Virginia. It is part of a highway tunnel installation project to increase capacity on a bridge tunnel.
The Challenge
During mining, the TBM, which is more than 40′ in diameter, began to pull pieces of sheet pile & wire rope through the face. To prevent further damage to the machine, tunneling was stopped. The machine encountered the debris approximately 250 feet short of the exit structure, underneath a constructed island.
The island is built out of relatively loose beach sand that’s commonly available in the area. The crown of the machine is approximately 25′ below grade, with the invert of the machine being about 70 feet below grade. Mean high tide is also about 25′ below grade.
In order to facilitate a hyperbaric intervention, the contractor needed a solid plug in front of and around the machine face. The criteria for the plug included:
- easily excavatable, to prevent issues for the TBM upon resumption of mining, and also to ensure that divers doing the hyperbaric intervention wouldn’t have issues removing grouted material in the case of grout entry into the machine face.
- low viscosity, to ensure uniform permeation into the soils in front of the machine, though they were relatively course (only 1% fines)
- readily available, in order to meet the incredibly short schedule requirement
The Solution
CJGeo proposed permeation grouting to create the plug using acrylic grout. Acrylic grout is:
- readily available through the mining supply chain
- very low viscosity, so well suited for permeating sands
- forms a stiff gel that’s stable, but still easily hand-excavatable
To perform permeation grouting up to 75 feet below grade, CJGeo proposed sonic drilling to install Tube-a-Manchette (TAM) pipes.
Due to the compressed timeframe, CJGeo subcontracted a sonic driller to install 86 different TAM wells, ranging from 25 to 75 feet deep. Once the first 10 TAM tubes were in place, CJGeo started placing acrylic grout through up to 10 simultaneous TAM pipes, using straddle packers and a PLC-controlled grouting system.
CJGeo was onsite within 10 days of the first call. Then, over 23 calendar days, CJGeo successfully installed more than 85,000 gallons of acrylic grout, at rates of nearly 15 gallons per minute.
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Tunnel Shaft Sinkhole Grouting
The Job
This tunnel shaft sinkhole grouting project is located in Newport News, Virginia. It is located outside the gate for Pier 2 at Newport News Shipbuilding, home to the deactivated USS Enterprise (CVN-65). As part of water and sewer upgrades in the area, multiple shafts were excavated to facilitate guided pilot tube bores.
The Challenge
At a shaft in the middle of an intersection, the dewatering well driller was unable to maintain circulation. This resulted in incomplete dewatering points. During excavation of the ring beam and liner plate shaft, the floor blew out after excavating through a fat clay layer. The fat clay is underlain by a highly permeable flowing sand.
When the floor blew out, the shaft, which is roughly 30 feet diameter, settled up to a foot on one side, and the shaft flooded in a few minutes. Multiple large sinkholes opened up around the perimeter of the shaft.
The Solution
The utility contractor, who was sinking the shaft, reached out to CJGeo for a solution. The only way to salvage the situation was to adequately dewater the site, which was even less possible due to the extensive voids around the shaft.
CJGeo visited the site, and made a few recommendations. First was to grade the site to direct the surface water away from the structure. There were multiple blocks of surface stormwater flowing directly into the area around the shaft. Second was to perform polyurethane compaction grouting around the entire structure to fill voids under the pavement and around the liner plates.
CJGeo mobilized a geotechnical polyurethane grouting crew to the site the following day. Using CJGrout 35NHV61, the crew filled approximately 70 cubic yards of sinkholes. Grout uniformly migrated through the liner plates, indicating that voids were continuous around the perimeter, and across the full depth of the shaft.
After CJGeo completed the grouting work, the dewatering contractor was able to successfully drop four wells around the shaft. By dewatering the underlying flowing sands, the contractor was able to resume excavating the shaft.
A few weeks after stabilizing the shaft, the two tunnels were successfully completed from the shaft. A CJGeo cellular grouting crew then grouted the annular space on both tunnels.
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NCDOT abandonment grouting
The Job
This NCDOT abandonment grouting project is located outside of Chapel Hill, North Carolina. The abandonment grouting is the final step in a gravity main replacement project. The scope requires filling 3,023 linear feet of 24″ RCP gravity sewer with NCDOT-approved flowable fill.
The Challenge
This gravity main runs entirely in a cross-country backwoods right of way. Along the alignment, there are a few road crossings, which require the NCDOT approved material.
Because the new pipe is in the same right of way, there are multiple locations where new and old pipe alignments cross. This breaks it into a collection of smaller runs, as opposed to one continuous run of pipe.
The Solution
If this was one continuous run of pipe, it would be a great candidate for dry batch generation cellular grouting. The 352CY project volume would only take about two hours to fill.
However, being broken into multiple, shorter runs in the middle of the woods, meant that wet batch equipment was more appropriate from an access and productivity perspective.
CJGeo mobilized a wet batch crew to the site, and it took them two days to complete the work. There were a total of 11 runs of pipe and six placement points. The longest run was 1113 linear feet, the shortest only 56.
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NCDOT pipe abandonment
The Job
This NCDOT pipe abandonment project is located outside of Wilmington, North Carolina. It is part of a large highway improvement project to improve capacity in the rapidly expanding southern coastal North Carolina area.
The Challenge
NCDOT requires grout fill for most abandoned pipes within their right-of-way. Traditionally this is done using flowable fill mixes. Using flowable fill for short abandonment is generally pretty simple.
However, this project has more than 100,000 linear feet of pipe ranging from 6″ to 36″ to fill. Most flowable fill mixes won’t go more than a couple hundred feet in best cast conditions. The utility contractor was looking at having to dig up to five hundred access points to place flowable fill. That’s incredibly time consuming and costly.
The Solution
The utility contractor reached out to CJGeo about performing the abandonment grouting on this project, using low density cementitious material (cellular concrete).
Due to the highly variable pipe diameters and run lengths, CJGeo proposed a mix of wet batch and dry batch cellular concrete generation.
Wet batch was used for the lower volume runs. Dry batch is best suited for large volume runs. Over the course of a few months, CJGeo mobilized multiple times to fill runs as long as a mile at a time.
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Ohio Polyurethane Grouting
The Job
This Ohio polyurethane grouting project by CJGeo was for a short line railroad near Scio, Ohio. The railroad received numerous complaints from motorists about a settled grade crossing. The settlement of the precast grade crossing was great enough to also require a speed restriction for rail traffic.
The Challenge
When this precast grade crossing settled, the clips holding the rail to the crossing panels broke. This allowed significant differential settlement between the various panels. The differential settlement was up to two inches.
In order to install new clips, the panels generally have to be within 3/8-inches of the adjacent panels’ elevation. If any debris has accumulated between the rail foot and bearing surface of the precast panels, which in this case were Oldcastle’s StarTrack.
The Solution
Having repaired multiple precast crossings for this short line, they reached out to CJGeo about performing this Ohio polyurethane grouting project. CJGeo proposed CJGrout 40NHL geotechnical polyurethane grout to the railroad. CJGrout 40NHL is formulated for high dynamic loading environments, and is excellent for different settlement correction of thick pavements.
CJGeo mobilized a polyurethane grouting crew to the site. Due to relatively low traffic on the line, the customer was able to provide an eight hour window for the repair, and the DOT allowed a complete road closure, as the settlement affected both lanes, with the centerline being the worst spot on the crossing.
CJGeo crews used mechanical assistance to address some of the worst differential settlement. Cleaning the accumulated debris between the rail foot and panels was key to facilitating complete correction of the differential settlement. After CJGeo wrapped up the polyurethane grouting, the railroad’s maintenance-of-way crew installed new clips, replaced the boots, and patch the adjacent asphalt.
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RCP Joint Sealing
The Job
This RCP joint sealing project is located near Charlottesville, Virginia. The polyurethane grouting work was subcontracted to CJGeo as part of an on call contract for stormwater structure and dam maintenance with a municipality.
The Challenge
Pavement distress of an asphalt roadway over a small dam prompted an inspection of the triple barrel 48 inch RCP structure passing through the dam. Upon inspection, significantly less water was flowing through the pipes than was flowing through the downstream spillway.
On each of the three pipes, water was flowing out of the endwall around the RCP inverts. There was relatively little cover on the pipes. This would make open cut replacement relatively simple. However, the roadway is the primary access to a neighborhood. Thus, a trenchless grouting repair to address the joint failures and piping was optimal.
The Solution
CJGeo worked with the on-call contractor, and owner’s dam engineering consultant to design a grouting program that not only addressed the piping and joint leaks, but also the voids in the fill material between the pipes and roadway.
Over the course of two days onsite, a CJGeo polyurethane grouting crew grouted each of the three pipes using CJGrout 35NHV61 geotechnical polyurethane. 35NHV61 is provides adequate bearing capacity for typical roadway loading, performs identically in flowing water and dry environments, and is certified for potable water contact.
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North Carolina Annular Grouting
The Job
This North Carolina annular grouting project is located in Havelock, North Carolina. Havelock is home to Marine Corps Air Station Cherry Point. US 70 passes through Havelock, providing a critical link between New Bern and the coastal beaches of North Carolina.
The Challenge
As part of North Carolina DOT work to upgrade the capacity and increase safety of US 70, a number of wet utilities were upgraded and relocated. This required a number of jack and bore crossings of the existing roadway to avoid disrupting traffic. NCDOT requires annular grouting for jack and bore crossings of wet utilities, for anything with less than a 100 year design life.
The Solution
This project had two crossings needing annular space grouting. One was 120 linear feet of 42″ steel casing with an 18″ ductile iron pipe water line. The second was 86 linear feet of 42″ steel casing with an 18″ ductile iron water line.
A CJGeo cellular grouting crew successfully filled each of the two casings with CJFill-Ultra Lightweight cellular concrete in a few hours in a single day. Carrier pipe buoyancy was not a concern due the low density of the grout.
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Bridge Approach Grouting
The Job
This bridge approach grouting project is located near Lexington, Virginia. It is on Interstate 81, which has some of the highest truck traffic in Virginia. The Virginia Department of Transportation maintains this section of Interstate 81.
The Challenge
Settlement over time caused voids under three lanes of approach slab at an overpass structure. During precipitation events, the voids became saturated, and then act as diaphragm pumps. The high dynamic loads from the heavy truck traffic effectively pump the fines out of the saturated base materail.
Over time, this resulted in extensive deterioration of the adjacent asphalt pavement, along with distress of the concrete approach slabs.
The Solution
Working with the local bridge maintenance group and their on-call maintenance contractor, CJGeo proposed a polyurethane bridge approach grouting program to restore stability to the slabs. Previous repair attempts had used flowable fill to attempt to fill the voids below the pavement. This generally doesn’t work very well, and proved to not be suitable in this case, either.
Primarily constrained by maintenance of traffic concerns, CJGeo undersealed all three lanes of the approach over two nights. Grouting was done using CJGrout 40NHL, which is optimized for heavy loads, wet environments, and is capable of lifting settled pavements.
Because 40NHL cures to 95% within a few minutes, by the time the injection holes are patched, treated slabs and soils are ready for traffic as usual.
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