Analysis of Lifetime of a Tubular Research Structure on Antarctica

Abstract

Isolated at the centre of the Southern Hemisphere lies the world’s coldest, driest and windiest continent: Antarctica. Antarctica has no aboriginal population but since the beginning of the 18th century the continent attracted many adventurers and scientists who dedicate their studies to a wide range of research fields. The wish to conduct research and other activities on such a cold and remote place has to be responded with structures that withstand the extreme polar conditions. The German Alfred-Wegener-Institute (AWI), Foundation for Polar and Marine Research, has conducted research on Antarctica since 1981 and operates several bases on the Antarctic continent. The first German station, Georg von Neumayer (GvN), was a basis for four scientists conducting geophysical, meteorological and chemical research as well as for five personnel staff. The present study focuses on the Neumayer Station, built in 1992 after Georg von Neumayer had to be abandoned because of large deformations of the base’s outer hull. Like its predecessor, Neumayer Station is a subsurface research base erected on the Ekström Ice Shelf. Due to its location in an ice shelf the base suffers from a limited lifetime. Within the scope of this project a numerical model is developed to come to a more precise prediction of the lifetime of such a base. The snow-covered Neumayer Station is located in a 200 m thick ice shelf. The base consists of two parallel steel tubes, each of which is 8.40 m in diameter and around 90 m long, in which containers are inserted to accommodate living and working quarters. A numerical model has been developed to estimate the deformations of the tubes. The deformations observed result from the widening horizontal dimensions and shortening of the vertical dimensions as well as from the (unequal) settlements of the tubes. The output of the model shows that in an average (50%) accumulation case, the earliest moment of deformation larger than the acceptable maximum will be in the year 2009. Values have been given for larger acceptable deformations and other snow accumulation rates. This thesis study contributes to a design tool to assess future tubular bases. Other contributions in the discussion over a new German base will be the level of automation for a future base and the possibility of cooperation with other institutes.