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Compensation Grouting

Chinatown Station

Service Performed
Conceptual, preliminary, detailed design of underground caverns, egress tunnels and mined shafts; scheduling and cost estimating; risk management; specifications and tender. Onsite support during construction.
Estimated cost
$1,600,000,000
Commencement - Services
March 01, 2016
Completion - Services
March 31, 2018
Location
425 Market Street Suite 1700
San Francisco, CA 94105
United States
Geology description

The geology ranges from soft clay (Bay Clay) to stiff sands (Colma Sands) and competent to highly fractured rock (Franciscan Formation). The groundwater table is generally above the cavern springline.

Geology types
Description

Chinatown Station is the Northern Terminus of the Third Street Light Rail Project, which is located in a dense urban neighbourhood, underneath a busy street and directly adjacent to numerous old buildings, as well as one high-rise building. The station encompasses a Cut-and-Cover headhouse for passenger entry, three large station caverns and an emergency egress shaft. In order to minimise excavation volume and optimise cost and schedule, the ventilation ducts are located below the platform level, and routed into the headhouse.

Activity
Construction methods
Special Construction techniques
Barrel Vault Method, Compensation Grouting
Tunneling under
Groundwater control
Tunnel length
2.7km
Project number
358E
Final cost
$1.6 billion USD
Completion date
Ongoing