The Job
This Upham Brook annular space grouting project is located in central Virginia. A sewer trunkline expansion in Richmond, Virginia required five bored road crossings ranging from 60″ to 72″.
Tunnel lengths are from 200LF to nearly 600LF. Mining is through rock using slurry micro-tunneling. One tunnel had mixed face conditions, which was unanticipated.
The design engineer required cellular concrete for annular space grouting due to run length, and buoyancy control of the carrier during grouting.
The Challenge
Not many; the longest run on this project, 600LF is a relatively short distance to push cellular concrete. Three of the four tunnels are round. The fourth tunnel is a combination of a round, MTBM-mined tunnel that transitions to a hand mined arch. The hand mine arch was to rescue the MTMB, which became stuck under a triple track CSX rail line. There was very poor access (the rescue shaft is in the CSX right of way).
The Solution
CJGeo proposed 38lb/cuft non-permeable CJFill-Standard low density controlled low strength material to meet the designer’s 200psi 28-day compressive strength requirement.
Over four different mobilizations, CJGeo successfully placed approximately 900CY of annular space grout.
The LD-CLSM generation was wet batch. Wet batch generation was chosen due to the relatively small daily volume of material placement and very tight sites.
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Facing a similar challenge to this Upham Brook 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.
