ABSTRACT
Underground space development as part of airport infrastructure is relatively new but is fast becoming a feature in most of the large airports. This is mainly due to the rapid growth in the numbers of passengers which in turn requires the expansion of existing facilities or building new. The vast above ground space an airport occupies, strict safety and security restrictions to move freely at the ground surface as well as the need for quick access to the aircraft, terminals and in between terminals are other reasons for promoting the construction of facilities underground.
The key underground infrastructure at airports are roads and rail tunnels as well as stormwater, sewer and utility tunnels. Some airports also have tunnels for the pedestrians, baggage handling and people mover systems. Giving due consideration to underground space development and planning these underground infrastructure at the initial master-planning stage will later aid in aerodrome efficiencies and seamless operations.
Construction works below runways and taxiways necessitate careful considerations to prevent ground settlement or sinkholes. The International Civil Aviation Organisation (ICAO) has set standards and recommended practices with respect to permissible runway slopes and surface roughness of pavement. These in turn govern the allowable ground settlement arising from construction of tunnels under runways and taxiways. In addition, there are further considerations that apply to construction works at airports.
The paper covers key and unique challenges related to the planning, design and construction of underground infrastructure at airports together with feasible solutions.
