January 12, 2023 marked an important mile-stone on Los Angeles County Metropolitan Transportation Authority’s (LA Metro) Westside Purple Line Extension (WPLE) Section 2 Project, when the second and final tunnel boring machine (TBM) successfully completed its journey and arrived at the interface with WLPE Section 1. This milestone represented the conclusion of tunnel excavation of the 2.59 miles (4.17 km) of twin-bore tunnels that make up Section 2 of the overall project.
Tunneling commenced in April 2020 and experienced several notable challenges during its duration. These included proceeding under the Beverly Hills High School, excavation under several busy thoroughfares (including Wilshire Boulevard), repair of one the TBM’s cutterheads after 1,300 feet of excavation, passage through the Wilshire/Rodeo Station, and the successful alignment connection with the WLPE Section 1 tunnels. The tunnel alignment was monitored by an extensive geotechnical instrumentation monitoring program, and the tunnel excavation was completed within the anticipated response parameters with no noticeable ground movement at surface.