大型野外シュートを用いた雪崩実験, その2 -雪塊の衝撃特性- [in Japanese] Snow avalanche chute experiments II : Impact characteristics of snow blocks against walls, posts and disks [in Japanese]
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雪崩実験シュートを用いて, 雪塊の壁, 杭および小円板に対する衝撃実験を行い, その衝撃特性を明らかにした. (1) 衝突画像と衝撃波形との対応から, 高速変形時の破壊形式を, 脆性破壊, 流動破壊1および流動破壊IIの3つに分類した. (2) 雪塊運動量と衝撃力積の比較では, 壁の場合はほぼ等しいが, 杭と小円板では中密度以上の乾き雪に周辺効果が現れ, 衝撃力積が雪塊運動量を上回った. (3) 衝撃圧が流体場にある物体の抵抗とした場合の最大衝撃圧の抵抗係数は, 衝突対象の違いにかかわらず, すべてほぼ3で表された.定常衝撃圧のそれはほぼ1となった.
The impact pressures of snow blocks against walls, posts and disks were measured using an artificial avalanche chute and a high-response recording system. Rectangular blocks were used for the walls and posts, and cylindrical blocks for the disks. The images of impacting snow blocks were recorded with a high-speed video system. In analyzing impact images and impact wave forms, three fracture types of snow blocks were identified. Momentum of snow block on the collision area of obstacle was calculated and compared with the measured total impulse on the obstacle. In the case of dry snow with medium or high densities, the measured impulses on posts and disks were larger than the calculated momentums. When the obstacles were treated as resisting bodies in the fluid flow, the resistance coefficients, k, for the maximum pressure were close to 3.0 irrespective of obstacle shapes, and k values for the stationary pressure were nearly unity.
- Journal of the Japanese Association of Snow and Ice
Journal of the Japanese Association of Snow and Ice 59(3), 189-199, 1997-05-15
The Japanese Society of Snow and Ice