The tunnel boring machine cutterhead and shield are now fully retrieved from below Flower Street in downtown Los Angeles’s Financial District. After completing the first of two tunnels for the Regional Connector project, crews worked on weekends to disassemble and transport the machine’s largest components back to Little Tokyo.
The images show workers opening the street to extract shield segments with the use of a gantry crane. As the name implies, the shield is the protective barrier between the earth and workers and equipment in the tunneling machine.
In order to connect the tunnel to the 7th/Metro Station, a tunnel box will be excavated from 4th Street to just south of 6th Street using a process known as “cut-and-cover.” With this method the street pavement is removed, a trench for the tunnel is dug and once the tunnel box is complete, the street is restored. Temporary road decking allows excavation to proceed while traffic is maintained on the surface.
The next portion of deck installation starts south of 5th Street in September.
Crews are now rebuilding the machine at the east end of the Connector’s alignment in Little Tokyo and will prepare to start excavating the second tunnel at the end of the summer.
The project is linking the Blue, Expo and Gold Lines to create faster light rail trips to and through downtown Los Angeles. The project is expected to be complete in 2021 and is funded by Measure R, a federal grant and other sources. Here’s the project home page.