Shiro Kubota, Yuji Ogata, Yuji Wada, Ganda Simangunsong, Hideki Shimada, and Kikuo Matsui
久保田士郎，緒方雄二，和田有司，シマングソン ガンダ，島田英樹，松井紀久男
p.124-128
Abstract
Behaviors of cylindrical rock specimen under dynamic load have been investigated by proposed test. The Hopkinson's effect at free end of specimen has been employed in this dynamic test. The PMMA pipe filled with water is arranged between the explosive and cylindrical rock specimen, and the length of the pipe is varied to adjust the strength of dynamic loading. A series of the dynamic test were carried out for Kimachi sandstone. The propagation processes of the tensile stress in the specimen were reproduced by the velocity profiles. From the distributions of the tensile stress near the free end, the relationships of the region or position of fracture surface and the stress distribution have been clearly understood.
著者らが提案した試験方法によって動的荷重下における岩石試料の挙動が調べられた。試験ではホプキンソン効果を応用した。水で満たされたPMMA製の管が爆薬と岩石試料の間に配置され，PMMA管の長さが動的荷重の大きさを調整するために変化させられた。来待砂岩に対して，一連の動的試験を行った。実験により得られた自由端での速度履歴より，試料中の引張波の伝播過程が求められた。引張波の応力分布から，破断が起こる領域と位置と応力分布との関係が明らかになった。
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Keywords
Dynamic tensile strength, Sandstone, Emulsion explosive, Free surface velocity, High speed photography
