Lake Mead Intake No. 3 Shafts and Tunnel
Vegas Tunnel Constructors (Impregilo/Healy JV)
This design-build project for the Southern Nevada Water Authority was awarded to Vegas Tunnel Constructors for $447 million. The work includes an access shaft 600 ft deep and 15,000 ft of rock tunnel to be mined with a convertible 7.2m Herrenknecht TBM, capable of operating as a hard rock machine in open mode and as a full Mixshield in poor rock and/or with high water inflows, and lined with 20-ft diameter precast gasketed segments. Also included is a new Intake Riser structure constructed 350 ft below the surface of Lake Mead, and miscellaneous site and ancillary work.
Project design has been completed by Arup USA in conjunction with Brierley Associates. All underwater excavation and structural work has been completed.
Excavation of the Intake Tunnel is under way, with a long section being excavated in a very complicated geology with large groundwater flows. Closed mode excavation with face pressures of up to 14 bar has been employed in the first 2,800 ft, along with an extensive pre-excavation and ground improvement program. Good progress is being experienced in open mode conditions.
Project Director: Jim McDonald; Project Manager: Jim Nickerson; Construction Manager: Renzo Ceccato; Chief Construction Engineer: Roberto Bono; Senior TBM Engineer: Nicola Donadoni; Staff Engineers: Erik Hornaday, Claudio Cimiotti, Nihad Rajabdeen, Paul Bennett, Joey Cadavid; Tunnel Superintendent: Chris Gomez; Walkers: Mike Revis, Brian Comfort, Willie Flores; Plant Manager: Greg Cook; Safety Manager: Vaughan Hargrave; QC Manager: James Grayson. For SNWA, Construction Manager: Dave Neil. Information: Jim Nickerson, (702) 893-2300.