ECAcontractor member Golden State Boring dug in to a $2.7 million tunnel project in northern San Diego County providing the services and expertise the company has come to be known for after nearly three decades. At the helm is company president Jeff Johnson who makes it all a reality
Overall, the project encompasses removal, relocation and replacement of two and a half miles of the Escondido Canal that crosses the San Pasqual Indian Reservation in northern San Diego County.
The contract includes three major components: a desilting basin, a replace-in-place canal section, and tunneled pipeline section.
For the pipeline section project Golden State was called on by general contractor Sukut Construction to bore a 350’ long tunnel that will accommodate a 60” diameter pipeline as a section of a new 1.5 mile long alignment across portions of the San Pasqual Indian Reservation, easements across private parcels, and the public San Pasqual Underground Project right of way in North Lake Wohlford Road.
For their exacting alignment Golden State relied on the Topcon laser pipe guidance system to monitor tunnel direction excavated to the approved designed alignment.
To achieve their boring objectives Golden State utilized a customized Antra Quip 2 head boring tool mounted on a six foot boom on an Eimco 921 tunnel loader.
To remove the muck the road header was backed out of the tunnel and a secondary unit was used to remove the loosened muck from the heading. The road header was equipped with water nodes for dust suppression.
After the heading was mined to the horseshoe rib and lagging dimensions, the rib steel was hand set and the lagging installed providing the initial tunnel support. Owing to the short tunnel distance, personnel could easily walk to the headings.
Project Manager is Jeff Johnson, a man with 45 years of experience in the boring and tunneling industry.
Project Supervisor was Derek Brinkle, an OSHA tunneling certified professional with 15 years experience in the business.
In the overall work, prime contractor Sukut constructed the pipeline within a 350’ long tunnel to minimize environmental impacts to a riparian area in this section.
The project’s 110’ by 32’ desilting basin’s hydraulic structure within the 100’ canal right of way required construction of large retaining walls and an all-weather access road, which included a concrete box tunnel.
In addition, the first half mile of the open canal is replaced with a shallowly buried 60” wide by 48” high precast concrete box culvert.
Finally, for the pipeline section, the box culvert transitions to a buried 60” diameter pipeline in a new 1.5 mile long alignment across portions of the San Pasqual Indian Reservation and across other public and private parcels.
An ECA member since 1994, Golden State was founded by Jeff Johnson and Rick Ander son and has emerged to become a leader in the trenchless technology sector in the western U.S.