The Job
This Illinois polyurethane grouting project is located next to the C-concourse at O'hare. During excavation of a tunneling shaft as part of a stormwater project, the shaft walls failed. This resulted in significant soil loss into the shaft, and substantial surface settlement. The owner directed the shaft contractor to perform remedial grouting before performing pavement restoration.
Performing the polyurethane grouting.
The Challenge
The shaft failed shortly before the manhole structure inside it was completed. There were significant concerns about the ability of the shaft to tolerate any additional pressure. Therefore, the safest way to proceed was for the contractor to backfill the shaft around the structure prior to performing grouting around the structure.
The Solution
Drilling for grout tube installation
CJGeo proposed polyurethane compaction grouting using CJGrout 22SHV. 22SHV is a slow, hydro-insensitive void filling foam suitable for filling very large voids without scorching. This was important due to large visible voids outside of the shaft lagging.
Due to layers of recycled asphalt used as backfill, percussion installation of the injection tubing was unlikely. So, CJGeo mobilized a contract drilling contractor who augered through the dense mixed fill layers on top into the target grout zone. They were also able to perform pre & post grout DMT testing. However, post-grout, the layers of recyled asphalt were too dense to penetrate.
CJGeo was onsite for fewer than three days. Because CJGrout 22SHV cures within a few minutes, the customer was able to install the new pavement the following day.
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