Beacon Hill Station Shotcrete Application

The Beacon Hill Tunnel Station is currently under construction as part of the Sound Transit Central Link Light Rail Line in Seattle, Washington. With an excavated depth roughly 49 m (160 ft) below ground, the station is the deepest to be constructed in soft ground in North America. Station excavation is being completed using the Sequential Excavation Method (SEM) with shotcrete used for both the initial excavation support lining and for portions of the final structural lining. This paper presents the general design basis used for construction contract bidding and provides a review of the current excavation status with specific emphasis on lessons learned from field application of both dry-mix Steel Fiber Reinforced Shotcrete. (SFRS) and conventional wet-mix shotcrete used for initial excavation support of the tunnel.