NATM for Singapore

Synopsis:

Singapore has some experience in the application of NATM for tunnel construction. To date, tunnels of smaller size have been constructed using this technique. The Fort Canning Tunnel is a three-lane vehicular tunnel with a span of approximately 48 feet and is the first wide span tunnel in Singapore constructed by NATM. Its location in soft ground combined with a high groundwater elevation and shallow cover of about 12 feet called for special design considerations in particular in the use of systematic pre-support techniques. A special pre-support umbrella (AGF) consisting of steel pipes and synthetic grouts for ground improvement is utilized. The tunnel design has been developed in close cooperation with the contractor Sato Kogyo in a designbuild framework.As a result of the tunnel collapse that occurred on a cut-and-cover construction for Land Transit Authority’s subway system the design development was subjected to a rigorous review and checking process.

NATM for Singapore
2006 North American Tunneling Conference Proceedings
June 10-15, 2006
Chicago, Illinois