Construction of unlined tunnels for icecap stations: Fid-Bau Portal

Construction of unlined tunnels for icecap stations

Walsh, M.R.

Facilities operations in a polar icecap environment present many unique challenges. Coping with the extreme cold temperatures, the darkness during the long winter months, and blowing and drifting snow all hamper installation, maintenance, and repair operations. For over 40 years, the concept of using tunnels for utilities and personnel in polar environments has been tried with mixed results. In 1991, the U.S. Army Cold Regions Research and Engineering Laboratory initiated a project to develop, fabricate, test, build, and deploy a system for the machining of unlined tunnels at the Amundsen-Scott South Pole Station. A system based on a modified tracked excavator was deployed to Antarctica in January 1996 for testing. The system was modified and redeployed the following summer to create a subsurface utilidor. A 120 m long, 2-m by 3-m tunnel was machined into the firn at the station over the course of 10 days. The tunnel, at a maximum depth of 16 m, is currently being used for the main station's wastewater discharge line. At a near-constant -40 degree, the well-lit tunnel, secure from the elements, has already proven its worth during routine and emergency maintenance operations during the harsh polar winters since 1996. Further tunnels have been planned as part of the new U.S. South Pole Station.