SPECIAL SHEET PILES SUPPORT SOIL AS CREWS DIG UNDER TAXIWAY

A New Jersey subcontractor is working double shifts to finish an approximately 125-ft (38-m) long portion of the 2,000-ft (610-m) long twin-cell tunnel beneath two taxiways at New York City's John F. Kennedy International Airport by May 15, 1999. The tunnels will be part of a future 8.4-mi (13.5-km) light rail system. Construction of the tunnel section has closed the taxiway, which must reopen for the summer season, or the contractor faces penalties of $5,000 a day. The cut-and-cover tunnels include a 33-ft (10-m) wide cell for the mostly elevated two-track light rail line to descend underground as it approaches the airport terminals and a 38-ft (12-m) wide cell for a two-lane restricted service road. It will replace an airside road connecting to the nearby Van Wyck Expressway. Up to 34 ft (10 m) deep, the excavation incorporates both steel sheet pile vertical supports and chemical grouting to dewater soil--a combination that may be a first in the United States. In September 1999, the contractor will begin digging under the other taxiway from the airport side to complete the tunnel, repeating the work in another 6-month contract.