The Job
This Ohio annular grouting project is part of Akron’s Northside Interceptor project. The Northside Interceptor project is a large CSO mitigation project designed to improve regional water quality.
The annular space grouting on this microtunnel is just one of multiple scopes CJGeo has on this project. Our scopes primarily involve annular grouting for various diameter/method tunnels. These include hand mining, road header, TBM and drill and shoot.
The Challenge
This microtunnel is 550 feet of 60 inch inside diameter concrete jacking pipe, with 50.8 inch outside diameter HOBAS carrier pipe. Due to the relatively tight annulus, and long distance of the tunnel, the microtunneling subcontractor was concerned about ensuring complete fill of the annulus without damaging the brand new carrier pipe. They reached out to CJGeo to assess the viability of grouting the annulus in a single pass.
The Solution
CJGeo’s in house engineering team analyzed the tunnel to determine a strength requirement, and associated density to achieve the strength requirement given locally-available cement. Next, we performed buoyancy calculations to configure a buoyancy control plan which would facilitate single lift grouting. Single lift grouting is advantageous because it:
- designs out the safety risks of having personnel inside of pipes
- eliminates the need for swiss cheesing brand new pipes with grout placement ports
- minimizes the risk of trapping air pockets or fouling slick lines
After acceptance of the grouting program by the EOR, CJGeo mobilized to the site and installed roughly 100 cubic yards of 55lb/cuft CJFill-Standard cellular grout. Confirmation of fill on this Ohio annular grout project was uniform grout venting from the 12 o’clock port at the far end from placement. Peak pumping pressure was less than 5psi, while placing at approximately 100 cubic yards per hour.
Speak With An Expert
Facing a similar challenge to this Ohio annular 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.
