Planning, Design and Construction of the Regional Connector Bored Tunnels-An EPB Tunneling Case History

摘要

Los Angeles County Metropolitan Transportation Authority's (Metro) Regional Connector Transit Corridor (RCTC) is a $1.75 billion (US) design-build, underground light rail project, connecting two existing rail lines (Metro Contract No. C0980). The project alignment runs through the heart of Downtown Los Angeles, with construction ongoing in the city's Little Tokyo, Bunker Hill, and Financial Districts. It will connect the existing Metro Gold Line to the Blue and Expo Lines, providing one-seat rides in the North-South direction from Azusa to Long Beach and East-West from East Los Angeles to Santa Monica, allowing passengers to bypass Union Station for transfers to the Red and Purple Lines. This paper presents a case history of planning, design and construction efforts to achieve the successful completion of the Bored Tunnels. Further, this paper outlines the pro-active partnership between the owner, Metro, and the Design Builder, Regional Connector Constructors (RCC, a joint Venture of Skanska USA and Traylor Bros., Inc.) with design services provided by Mott-MacDonald (MM) and Hatch, to address project schedule and technical challenges, including various differing site conditions and critical settlement control done in low-cover EPB tunneling.