Two 12 ft x 12 ft horseshoe shaped tunnels approximately 300 foot long driven via Roadheader. Ground support consisted of wide flange steel sets with shotcrete lagging. Subsequent to tunnel excavation, 108” diameter welded steel pipes were installed, and the annuluses filled with cellular grout. Multiple permanent sculpted shotcrete soil nail walls were also located throughout the water treatment plant. The largest single wall area is approximately 23,000 square feet and has a maximum retained height of approximately 8 feet. Several micropile foundations were also constructed at the site.
Owner:
San Francisco Public Utilities Commission, Bernie Mark, Assistant Construction Manager
General Contractor:
Kiewit Infrastructure West Co., Clint Cole, Project Manager
Engineer/Architect:
Jacobs Associates Glenn, Markland Boyce, Project Engineer
DTDS Project Manager:
Brett Mainer & Steve McCullough
Completion:
December 2012
Service Type:
Tunneling
Project Scope:
Tunnel, Shaft, Soil Nail Wall, Soldier Piles, and Micropiles