Project Two-Mile Bar Tunnel

Jamestown, CA

Drill Tech was contracted to perform new tunnel construction work adjacent to Oakdale Irrigation District’s South Main Canal. OID decided to build a new tunnel for canal irrigation water conveyance from Tulloch Reservoir to bypass over a mile of existing canal that was subject to seismic and slope failures on steep mountain slopes.

Completion:

Service Type:

Project Scope:

2019

Tunneling

Tunneling, Drill & Blast, Soil Nails, Rock Bolts

New Tunnel for Canal Irrigation

Drill Tech was contracted to perform new tunnel construction work adjacent to Oakdale Irrigation District’s South Main Canal. OID decided to build a new tunnel for canal irrigation water conveyance from Tulloch Reservoir to bypass over a mile of existing canal that was subject to seismic and slope failures on steep mountain slopes.

The project included soil nail/shotcrete portal construction, mass surface excavation and haulage, tunnel construction using roadheaders, and installing diversion structures related to directing water into the tunnel away from the existing canal. The tunnel excavation was performed from both ends, one heading of which was performed completely under winter canal shutdown/outage periods. This portion was at the downstream portal and was terminated at 552’ leaving the remaining 5,397’ to be excavated from the upstream portal. Both excavations included ground support of shotcrete, rock bolts, and occasional steel sets. To complete the long stretch of tunnel from the upstream portal, Drill Tech installed a complex electrical distribution system with generators, high voltage transmission cables, and transformers to provide power to the heading for the roadheader. At the completion of tunnel construction, Drill Tech installed a final shotcrete liner and concrete invert for future irrigation water flows.

Owner
Oakdale Irrigation District
General Contactor
Drill Tech Drilling & Shoring, Inc.
Engineer/Architect
Condor Technologies
DTDS Project Manager
Brian Harris