Bulk Settlement of the New Elevated Station at South Pole

摘要

The US Antarctic Program is nearing completion of a 9-year project to reconstruct its primary facility at the geographic South Pole. The new building is elevated and jackable to accommodate its presence in a snow accumulation zone, The building's foundation consists of rigidly connected grade beams to which 36 columns extend upward 13-ft (4-m) to support the new state-of-the-art living and scientific facility.rnDesign of the Elevated Station recognized that bulk and differential settlement of the facility would occur into the 9,295-ft (2,833-m) deep substrate (glacial ice overlain by firn with dense windblown snow int the uppermost 100 ft (30 m)). Routine facility maintenance is required to level and shim columns when it is apparent that differential settlement limits are near. (Differential settlement analysis is discussed in a separate paper.)rnIn addressing bulk settlement, designers of the Elevated Station anticipated the need for major jacking at each column and insertion of 12-ft (3.7-m) extensions. It was calculated that this would be required approximately every 15 years. Two column extensions were envisioned, giving the facility a potential life span of about 45 years.rnThis paper analyzes the settlement data for the Elevated Station from the placement of the first columns (November 2000) until January 2005. We show that column settlement slows from a rate of over 4 inches (10 cm) per year during the first year of existence to near 2 in (5 cm) per year during their fourth year in place. Settlement data so far match the pattern shown in the literature for laboratory tests of static loads on snow.