Project Calaveras Dam

The Calaveras Dam Replacement project is a replacement of the existing earthen dam undertaken by the San Francisco Public Utilities Commission, with the general contractor as Dragados-Flatiron-Sukut Joint Venture. Drill Tech was subcontracted to perform deep soil mixing to stabilize the disposal site, to excavate a 154-ft deep shaft, five starter tunnels (12’ dia. x 60’ each) from within the shaft, and multiple soil nail, rock bolt and tieback walls to stabilize the abutment excavations and spillway. The ground improvement was performed using 238ea CSM panels up to 78 feet deep that were all keyed five feet into rock. The shaft was excavated with drill and blast techniques, and the tunnels were driven with an Alpine AN50 roadheader. The total quantity of soil nails, rock bolts and tiebacks on the project exceeded 100,000 lineal feet.