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.
NY Grade Crossing Repair
The Job
10 panels of StarTrack modular grade crossing tubs settled in an urban street crossing owned by a short line. As a result of the settlement multiple clips broke. This caused the panels to pump.
The Challenge
The crossing tubs settled, and when crossed by trucks, pumped water containing the sub-ballast up between the tubs and adjacent pavement. The adjacent track also settled significantly.
The Solution
CJGeo proposed grouting immediately below the panels, and also into the underlying disturbed subballast using CJGrout 48NHL geotechnical polyurethane grout.
The CJGrout 48NHL was injected through 5/8″ holes drilled through the panels. The settlement pattern of each panel determines the specific hole spacing. It takes about five minutes for the grout to cure to 95% of its ultimate strength.
CJGeo performed the StarTrack modular grade crossing repair without impacting rail traffic. The facility was able to function normally throughout the repair, which took less than a day.
New York Tub Crossing Lifting
The Job
Eight panels of StarTrack modular grade crossing tubs settled. As a result of the settlement multiple clips broke.
The Challenge
The crossing tubs settled, and when crossed by trucks, pumped water containing the subballast up between the tubs and adjacent pavement. The crossing was the only entrance into an industrial facility that took two trains per day. Because of limited onsite storage, rail service couldn’t be disrupted at all.
The Solution
CJGeo proposed grouting immediately below the panels, and also into the underlying disturbed subballast using CJGrout 48NHL geotechnical polyurethane grout. CJGeo performed the grouting without impacting rail traffic, and the facility was able to function normally throughout the repair, which took less than a day.
Pit Fill With Lightweight Flowable Fill
The Job
An abandoned water treatment plant at a federal facility was being rehabilitated and brought back into service.
The Challenge
As part of the project, all activities were being moved above grade. A 12′ deep tank below the building floor needed to be filled before installing a new floor. The pit had been designed for holding water, and the majority of the pit was below ground water levels.
The designer had two competing interests–given the closeness of the water table to finish floor, avoid any buoyancy of the fill material, while using the lightest possible material to avoid inducing any settlement.
The Solution
CJGeo proposed filling the pit with CJFill-UW, at 70lbs/cuft. At 70lb/cuft, there are no uplift concerns, and the material is just barely denser than water, which helps minimize the amount of anticipated settlement. To help ensure future excavatability, CJGeo used a sanded base slurry (as opposed to the usual neat mix slurry) to generate 830CY of material.
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.
Illinois Spillway Grouting
The Job
A spillway serving as a dam for a lake owned & maintained by a property owner association outside of Carbondale, Illinois stopped having water flowing over the spillway. The property owners determined that the lake was draining through voids under the spillway slab. This made them concerned about destabilization of the spillway, which was the sole access for six homes.
The Challenge
The flow velocity was rather high, and immediately on the other side of the spillway was a 30′ cliff, that the water was designed to spill over as a waterfall. Given the extraordinary difficulty of retrieving any material washed over the waterfall, the grout had to have an exceptionally fast set. It also needed to provide adequate bearing capacity for the roadway slabs.
The Solution
CJGeo proposed grouting below the spillway with CJGrout 40NHL, which is usually used for differential settlement correction. CJGrout 40NHL performs well for differential settlement correction because it reacts very quickly, and is used for medium duty lifting, such as highway pavement, so it would provide more than enough bearing capacity.
The owners were very excited that it would be significantly less expensive to grout the existing spillway than to have someone local install a portadam and replace the entire structure. CJGeo mobilized a single polyurethane grouting crew to the site, and they stopped the leaks and kicked all the water flow over the spillway in a single day.
