Los Angeles County Metropolitan Transportation Authority, Metro, announced that its first Tunnel Boring Machine has officially broken through to connect with the Wilshire/Western metro station in Koreatown, as part of Purple Line extension project.
TBM “Soyeon” is one of two TBMs to mine approximately 3.2-km of parallel metro tunnels between the future Wilshire/La Brea station and the existing Wilshire/Western station.
Soyeon was originally lowered into the ground at Metro’s Wilshire/La Brea station site in the Miracle Mile area of Wilshire last October. While advancing, the TBM burrowed about 18 m per day, working five days per week, 20 hours a day. The digging has taken 8 months to reach the bulkhead — the retaining wall at the face of the Wilshire/Western metro terminus. Metro anticipated future westward metro expansion and built the bulkhead wall as part of station construction.
A second TBM named “Elsie” that was launched six weeks after Soyeon is also expected to break through to Wilshire/Western later in June. When done tunneling this project section, both TBMs will have mined nearly half a million cubic yards of earth.
The TBMs were manufactured in Germany by Herrenknecht AG. Metro has contracted with Skanska Traylor Shea (STS), a joint venture to design and build the first section of the project.
“Our tunneling achievements to date prove that we can successfully mine through some of the most challenging conditions that any subway project anywhere in the world is likely to face,” Metro CEO Phillip Washington said.
Following the tunneling operation, Metro will focus on completing construction of its first three metro stations over the next three years.
The USD 9.8 billion Metro Purple Line extension project envisages the construction of a 14.5-km underground metro line served by 7 stations, from its current terminus in Koreatown to Westwood/VA Hospital in West Los Angeles. The first section is expected to be completed in 2023, the second in 2025, and the last one, in 2027.