An evaluation of the role of monitoring during the construction of shallow NATM tunnels in urban areas

摘要

Monitoring forms an essential part of the construction of NATM tunnels. After the collapse of two platform tunnels and the concourse tunnel at the Central Terminal Area, Heathrow Airport, in October 1994, an extensive evaluation of NATM tunnelling, including the role of instrumentation, followed. The paper critically evaluates the purpose of monitoring during the construction of NATM tunnels, with specific reference to shallow tunnels in soft soils in urban areas. The instrumentation used during the construction of the station tunnels at Terminal 4 is evaluated with regard to its purpose and performance during construction.