Construction of a 380-metre long, 85 to 100 metres wide, and 15 metres deep reinforced cut and cover tunnel for the Central Artery/Tunnel Project (Big Dig), including cast in place boat- and tunnel sections, geotechnical investigations, excavation and disposal of (non)hazardous waste materials, design and construction of slurry walls and sheet piled walls for earth retaining structures, dewatering systems and two temporary bridges.