Soft ground

Rapid excavation of shallow cut (2m) for slab placement. Safe tunneling beneath operational highway. Minimal disruption to traffic

The Santiago Metro network comprises five lines. The Linea 2 South extension included 2.5km dual track running tunnels and two stations with a maximum span of 16.2m. Further, an excavation of 60-65m2 running tunnel in combined top heading/bench with a subsequent invert excavation. Reinforcement consisted of lattice girders, welded wire fabric for initial lining and welded wire fabric for final shotcrete lining. Dr. Sauer and Partners assisted in the production of design criteria for the final design and produced finite element structural computations for the large station caverns.

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.

The Corsica Street Ventilation Shaft comprises the permanent pressure relief and ventilation adit connecting the down line running tunnel to the shaft and temporary access adit tunnel. The ventilation adit was designed as a permanent sprayed concrete lined tunnel built in two phases: primary and secondary linings. The required watertightness was reached by staggering the joint locations between primary and secondary linings, utilising internal curing agents and steel fibres in the secondary lining sprayed concrete and injecting flexible tubes into joints of the secondary lining.

The Wayside ventilation shaft is one of five needed to provide ventilation and emergency access for the London Tunnels section of the Channel Tunnel Rail Link. The tunnels were designed as permanent sprayed concrete-lined, constructed in two phases, temporary primary and permanent secondary linings. The required watertightness will be achieved by staggering the joint locations between the two linings, utilising internal curing agents and steel fibres in the secondary lining sprayed concrete and using injectable flexible tubes in the joints of the secondary lining.