積雪沈降力の一観測例

概要

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A measurement was tried to investigate the settling pressure actig on a body like a forest tree being enforced to move down in the snow pack. The measuring device consisted of a flat board, 50 cm long by 10 cm wide, placed horizontally by a prop at a height of 1 m above the level ground. The lower end of prop was connected with a pressure gauge in the underground room. The settling pressure of deposited snow acting on the board was indicated on the gauge. The board was lowered gradually in the snow pack by every half distance of natural setting, and the subsequent increase of settling pressure was observed.<BR>The observation was carried out during the snow season of 1967-1968, at which the maximum snow cover depth was 306 cm. The downward displacement to the board was given thirteen times within the range of 2-60 mm. When the board was lowered, the settling pressure on it became to zero and gradually began to increase in course of time. After one or two days, the settling pressure returned to about 60 % of that acting on a flat board of same size fixed at 1 m height above the ground, and finally it recovered to about 70 %. At the end of winter, no remarkable breakdown was seen in the stratified structure of deposited snow around the equipment.