What is the Gravity Pipeline Project?

The Gravity Pipeline (GP) Project consists of the design, construction, permitting, start-up, commissioning, and closeout of approximately 17,600 feet of wastewater gravity FRP pipe inside a concrete-segment tunnel. The work includs three shafts and will interface directly with the Front of Plant (FoP) Project at the Receiving Lift Station (RLS). Work is being implemented under a Progressive Design-Build procurement process.

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Gravity Pipeline Project

Last Updated October 2020

TBM Status and Monthly Update – October 19, 2020

Contractor partner Barnard-Bessac Joint Venture (BBJV) oversaw the progress of Salus, the tunnel boring machine (TBM), as it began continuous mining from the launch shaft towards the SVCW plant. This mining took place after a planned stoppage where BBJV disassembled the launch cradle and made modifications to the launch shaft, such as installing a drive unit and continuous muck conveyor system. This system hauls the muck from the face of Salus’ cutting tool and out of the launch shaft. The last thing BBJV installed in preparation for continuous mining was the California Switch (seen below), which allows supply rail cars to pass each other in the tunnel to promote efficient movement of supply materials in and out of the tunnel.
Safety is emphasized at all stages of the continuous mining process. BBJV conducts daily tunnel taskforce meetings and works closely with SVCW to monitor ground settlement.
BBJV staff visit stations in the tunnel and on the TBM to monitor the safety equipment, review safety equipment operations, and practice mine safety rescues on a regular basis.
As of October 19, Salus mined 1,787 feet from the launch shaft and built 351 rings.

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Gravity Pipeline Project

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