The Job
This HDD annular space grouting project is east of Buffalo, New York, under the New York Thruway. As part of distribution improvements, National Grid’s contractor bored 830LF through rock using HDD. The bore was 30″, with a 16″ HDPE casing, carrying three, 4″ HDPE conduits.
As part of the installation, the NY Thruway Authority call for casing back grouting, and the casing pipe’s annular space grout filling.
The Challenge
The proposed back-grout had to be:
- pumpable 830LF at very low pressure,
- dense enough to displace the 10 pound per gallon drilling mud, and
- provide sufficient strength to meet Thruway requirements.
The proposed annular space grout had to be:
- pumpable 830LF at very low pressure,
- light enough to not apply excessive pressure on the conduit pipes, and
- also provide sufficient strength to meet Thruway requirements.
The Solution
CJGeo proposed two different grout mixes to meet the project requirements. 85lb/cuft CJFill-Under Water casing backgrout for the displacement of the 10PPG (75lb/cuft) drilling mud. And 25lb/cuft CJFill-Ultra Lightweight annular space grout within the casing.
CJGeo’s crew mobilized to the site, and successfully performed the back-grouting and annular space grouting in a single day. A tremie pipe strapped to the HDD casing was used for the back grouting. By pumping the 85lb/cuft (11 pound per gallon) CJFill-Under Water to the low point, the drilling mud was floated out of the reamed hole annulus.
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Facing a similar challenge to this HDD annular space grouting project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
