Service Performed NATM / SEM station design and construction supervision.
Technical data
NATM Light Rail Station located 150 ft (46 m) beneath surface. Station complex includes central elevator/access shaft, concourse, opposing platform tunnels and cross passages. Platform Tunnel Section: 36 ft w x 31 ft h; Platform Tunnel Area: 925 sqft (86 m²); total Station Excavation Area: 63,000 sqft (5853 m²).
Geology description
Over-consolidated glacial clay and till with fracutured zones. Intermittent sand and silt layers with perched groundwater.
Description
The Beacon Hill Tunnels and Station are part of the 22.5km initial segment of the Sound Transit Central Link Light Rail Line that will establish a high capacity commuter connection from downtown Seattle to Tacoma. The 1300m running tunnel under Beacon Hill will be mined by Earth Pressure Balance Machine (EPB), while the deep mined Station will be constructed using slurry walls and the New Austrian Tunneling Method (NATM), referred to as Sequential Excavation Method (SEM) for this project.
