14TH St. - Greenline - Metro Tunnel
Washington, DC  (1994)

Park Road - Greenline - Metro Tunnel
Washington, DC  (1995)

Under major cities, tunneling through soft soils 
requires extreme caution, monitoring and expertise.

In building over one mile of twin tunnels for the 
Washington, D.C. subway system, the joint venture 
formed between KiSKA-USA and Kajima Construction 
utilized dewatering, chemical grouting, underpinning 
and slurry wall construction to stabilize soils and 
buildings adjacent to the excavation.

Open shield hydraulic excavator and precast segment 
liners were used for tunnel excavation.