Experimental results on the formation of hard compacted snow in Rikubetsu in northern Japan: A first step toward the construction of a compacted-snow runway on the Antarctic ice sheet

摘要

This paper describes the experimental methods and results on the formation of hard compacted snow in Rikubetsu in northern Japan during the winter of 1999. This basic research was the first step towards the construction of a compacted-snow runway on the Antarctic ice sheet. In Rikubetsu, we constructed three test fields(20m in length, 7m in width, and 0.4-1.0m in thickness) on compacted basal snow(approximately 0.05m in thickness). First, 0.1-0.35-m-thick layers of snow were deposited on the basal snow of the fields using a rotary snowplow. Next, the surface snow was smoothed using an excavator. Finally, the snow layers were compacted four times using a bulldozer. This entire process was repeated three to four times in order to construct 0.4-1.0-m-thick test fields. The ram hardness, snow density, and snow structure of these fields were investigated. A comparison with the criteria established by a U.S. scientist for a large aircraft-such as the C-130(Abele, 1990)-revealed that if snow in the form of three 0.2-0.25-m-thick layers is compacted four times by a bulldozer, it is sufficiently hard to serve as a runway at H68(69°11u279″S, 41°03u2734″E, 1204m a.s.l.) for a wheeled C-130. The Japanese Antarctic Research Expedition plans to conduct a feasibility study on the construction of the hard com-pacted-snow runway at this location.