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.
Nashville Basement Abandonment
The Job
This privately owned building was constructed inside of the basement of a previous building, but with a smaller footprint. Structural slabs were poured spanning between 4′ and 20′ from the original basement walls to the new basement walls.
The Challenge
As the structural slabs over the unused basement deteriorated, there were concerns about stability. Uses included a public sidewalk and parking/driveway area. The wall isolating the occupied space of the new building and the unoccupied area of basement was constructed of hollow clay block, metal studs & drywall. The maximum lateral load of any backfill material could only be 50PSF.
The Solution
CJGeo successfully filled the basement with 775CY of CJFill-UL7.5. The placements was done in 2′ lifts to meet the maximum 50PSF liquid head limit.
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.
Steam Tunnel Lightweight Backfill
The Job
As part of the expansion and renovation of the steam plant at Western Carolina University, a section of existing steam tunnel needed to be uncovered to install a new wall. The wall needed to be backfilled, and due to the condition of the tunnel, the lighter the backfill the better.
The Challenge
The site was exceptionally tight, and the location was more than 30 minutes from the closest ready mix plant. The backfill depth was nearly 15 feet, but the project was only about 1200CY, so doing 2′ lifts would have been slow and expensive.
The Solution
CJGeo proposed a CJFill-UL as a value improvement over the organic foaming agent cellular concrete that was specified. The architect and structural engineer approved the proposed change.
CJGeo mobilized a four person crew and a 200CY/hour mobile batch plant, and completed the work in three pours over two days. The CJFill-UL was generated using a synthetic foaming agent that can be placed up to 20 thick at a time, and is generated onsite directly from bulk cement, so isn’t dependent on ready mix plant locations.
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.
I-64 Soundwall Backfill
The Job
VDOT’s I-64 widening project is a multi-phase widening of Interstate 64 between Richmond & Newport News. This work occurred as part of Segment 2.
The Challenge
Approximately 150LF of a combination sound & retaining wall needed to retain more than 10′ of backfill. In order to keep the drilled foundation size consistent along the alignment, the backfill material needed to be significantly lighter than the soil backfill used in other segments, where there was minimal retained depth.
The material needed to be freely-draining and less than 40lb/cuft.
The Solution
CJGeo proposed backfilling the affected wall segments with 30lb/cuft CJFill-UL. Used extensively by VDOT for backfilling the retained zones of MSE walls, CJFill-UL provides significantly better bearing capacity than soils or aggregates, and once cured does not apply lateral loads to the structures it is placed against.
CJGeo placed approximately 200CY of CJFill-UL to backfill the wall in two pours, each approximately 5′ thick. The contractor was able to place the pavement subbase on top of the material the following day.
Willow Springs Crossings
The Job
BNSF’s Willow Springs Intermodal yard is a critical facility in United States’ freight rail network. The facility is colocated with a large UPS trucking operation, and BNSF has very tight time lines for transferring containers from inbound trains to UPS.
The Challenge
80 StarTrack modular grade crossing panels across 10 different crossings in the facility experienced settlement. The settlement was affecting the safe operation of yard trucks, causing delays in container transfer times.
Because of the 24/7/365 operation, and very tight performance times, there was no tolerance for downtime.
The Solution
CJGeo proposed grouting the affected panels with CJGrout-48NHL. 48NHL is specially formulated for differential settlement correction in high load applications, such as heavy haul rail.
CJGeo mobilized a polyurethane grouting crew with extensive modular grade crossing repair experience and grouted the 10 crossings over a period of five days onsite. The grouting was done without affecting rail traffic, yard truck operations, or performance metrics.
Savannah Tunnel Abandonment
The Job
The JW Marriott Plant Riverside is an adaptive reuse hotel project of a decommissioned power plant in Savannah, Georgia. As a thermal generation facility, there are extensive water tunnels below the structure. The tunnels were cast in place during original construction, and integrated into the pile supported foundation.
The Challenge
As part of the conversion from thermal power generation to luxury hotel, the tunnels needed to be filled. Due to concerns about inducing settlement with traditional flowable fill, the designer specified EPS Geofoam blocks. These would have effectively eliminated loads, but were deemed impossible to install.
The Solution
Someone onsite had heard of cellular concrete, so reached out to CJGeo. CJGeo evaluated the layout of the tunnels, isolation methods from the river, and designed a mix which would ensure both complete filling of the structures without adding any additional load.
CJGeo placed approximately 930CY of 20lb/cuft CJFill-UL cellular concrete over a period of three days. Because CJFill-UL is highly mobile, demo debris from the access holes for building bulkheads was left in the tunnels and encapsulated with the CJFill-UL.
