Decisions about the post-construction design have not been completed. There are many considerations currently being discussed, including not removing the shafts to allow for access into […]

As currently proposed, the shaft would be constructed with a diaphragm wall or concrete shell that would extend to the bottom of the tunnel where there […]

The Delta Conveyance program facilities, including tunnel shafts that are currently proposed to remain following construction, would be constructed at elevations greater than the 200-year flood […]

As currently proposed, a dedicated high-voltage power supply would be connected to the launch shaft sites to power the tunnel boring machine cutter head.

As currently proposed, the maintenance shaft sites would only be sized to remove the cutter head. The launch shaft sites would be sized to lift the […]

The ITR report’s note reflects the fact that the current tunnel corridors do not contain active faults and tunneling options themselves would not be uniquely affected […]

Many different types and brands of conditioners are used in tunneling based upon soil conditions present along the alignment. Conditioners are generally categorized as foams, polymers […]

The tunnel would be designed for seismic ground motions and forces generated using state-of-the-art seismic design modeling. Applicable engineering factors of safety for these dynamic forces […]

The greatest ground motions in a seismic event would occur near the ground surface. At the depths of the TBM and tunnel, the structure would probably […]

The applied TBM face pressure would be balanced against the soil and groundwater pressure by the TBM operator.

The greatest ground motions in a seismic event would occur near the ground surface. At the depths of the TBM and tunnel, the structure would probably […]

The equipment placed in the tunnel behind the TBM would include ventilation equipment, as will be discussed in upcoming Stakeholder Engagement Committee meetings.