The Job
This North Carolina permeation grouting project is located on I-95 in Lumberton. The area flooded in 2016 as a result of Hurricane Matthew, which washed out the bridge approaches of I-95 over a surface street and railroad tracks. This flooding event, and its extensive damage, kickstarted an extensive reconstruction project for I-95 in the area, focused on expanding capacity and reconstructing areas which had been hastily repaired after the storm.
Installing the tubing for permeation grouting.
The Challenge
At the railroad overpass in Lumberton, extensive erosion behind the abutments was addressed with sheet pile installation and backfill with clean 78 stone. This provided sufficient capacity to restore traffic, but as part of the reconstruction work, the civil contractor had to install a 25' tall soil nail wall in the 78 stone. The wall face was within a foot of the edge of pavement. This caused difficulties, in that during staged excavation the 78s would flow out from under the pavement, which was under traffic.
The soil nail wall contractor and general contractor determined that the 78 stone needed to be effectively glued in place to facilitate excavation without raveling, so they reached out to CJGeo.
CJGrout 20SDB returning to surface.
The Solution
CJGeo collaborated with the general contractor, the soil nail wall contractor, and the geotechnical consultant. Together, we chose CJGrout 20SDB geotechnical polyurethane for the permeation grouting. Standard permeation grouting often uses water-thin grouts like acrylate. However, controlling the mobility of these thin grouts in clean, open-graded stone is very difficult.
At our shop, CJGeo mocked up a fill section of 78 stone. This helped us determine the proper injection spacing to treat a two-foot thick mass of stone with CJGrout 20SDB. Following this mockup, a single grouting crew completed the onsite work in just two days. CJGrout 20SDB cures in minutes, allowing the soil nail wall construction to proceed immediately after grouting.
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