Evaluation of snow mechanics in Dome A, Antarctica and its application in telescopes

Dome A is one of the best astronomical observatory sites on the earth. Unlike any other area, the telescopes have to be settled on the snow ground. In that case, it is very important to analysis the Snow mechanics in Dome A. However, due to the complexity and high variability of the snow, research in this field has progressed slowly. This article first compares five methods previously used for analyzing snow strength, and selects the most suitable method to estimate the snow strength in Dome A. Through this method, combined with the temperature and density data at different depths in the Dome A area, the paper estimates the strength of the surface snow is ranging from 0.6Mpa to 2.5Mpa (0-10m depth), and by the ultrasonic velocity measurements, the elastic modulus of the snow in Dome A has also been estimated at the range from 4Mpa to 600Mpa. Finally, the size of the wood foundation and the tilt angle of the snow surface under the wind speed of 10m/s were calculated by the static analysis. According to the tilt angle analysis, it was found that the elastic modulus of the original snow is too low to meet the requirements of tilt angle for the 2m class telescopes, and the snow foundation needs to have a densification treatment to make its density up to 530kg/m³. This study should also provide an useful reference for future infrastructure buildings, such as the construction of an airport or installation of some other large precision instruments at Dome A.