@article{oai:kumadai.repo.nii.ac.jp:00031276,
 author = {片岡, みなみ and Kataoka, Minami and Obara, Yuzo and 尾原, 祐三 and 片岡, みなみ and Kataoka, Minami and Obara, Yuzo and 尾原, 祐三 and Vavro, Leona and Soucek, Kamil and Cho, Sang-Ho and Jeong, Sang-Sun},
 issue = {5},
 journal = {Journal of MMIJ},
 month = {May},
 note = {application/pdf, application/pdf, 論文(Article), Several testing methods have been proposed for evaluating the mode I fracture toughness of rocks. Since the fracture toughness evaluated from the different testing methods is generally not compared, what is still not wellknown is the effect of the testing method type on the fracture toughness. The effect of not only the testing method type but also the specimen size exists in the fracture toughness of rock materials. To clarify the effect of the testing method type and specimen size on the fracture toughness, many fracture toughness tests were performed in the previous experimental studies. However, the effect has not been elucidated because the number of the specimens is limited and the range of the specimen size is relatively small in the previous works. In this paper, firstly, three types of the fracture toughness test, the chevron bend (CB) test, semi-circular bend (SCB) test and straight notched disk bending (SNDB) test, were performed using Kimachi sandstone. Then, the SCB test was carried out using the same sandstone with various specimen sizes. As a result, the fracture toughness obtained from the CB and SCB tests were compatible each other. However, the SNDB tests estimated lower value of the fracture toughness than the others. From the results of the SCB tests with various specimen sizes, the fracture toughness increased with increasing radius. Based on the results, the effect of the specimen size on the fracture toughness and the differences of the fracture toughness obtained from the three testing methods were discussed., 岩石のモードI 破壊靭性を評価するための試験法がこれまでに数多く提案されてきているが，同じ岩石の破壊靭性を異なった試験法で評価し，得られた結果が比較されることはまれである。このため，破壊靭性に及ぼす試験法の違いが明らかにされているとは言い難い。また，岩石の破壊靭性は試験法の違いだけでなく，用いる供試体寸法によっても影響を受けると考えられる。これらの影響を明らかにするために，様々な破壊靭性試験が行われてきた。しかし，これまでの実験では，同じ岩石で作製された供試体数が十分でなかったり，あるいは供試体寸法の違いの範囲が狭かったために，それらの影響を明らかにするまでに至っていないと考えられる。
　本論文では，来待砂岩を供試体として用い，3 種類の破壊靭性試験法，すなわち，CB 試験，SCB 試験およびSNDB 試験を実施し，破壊靭性に及ぼす試験法の影響を検討するとともに，半径12.5mm 〜150mm の範囲の供試体を用いたSCB 試験を実施し，供試体寸法の影響を検討した。この結果，CB 試験とSCB 試験による破壊靭性はほぼ同等の結果を得ることができたが，SNDB 試験の破壊靭性はそれらの値より小さく評価されることを示した。また，供試体寸法が大きくなるとともに破壊靭性も増大することを明らかにした。, https://www.jstage.jst.go.jp/article/journalofmmij/135/5/135_33/_article/-char/en},
 pages = {33--41},
 title = {Effect of Testing Method Type and Specimen Size on Mode I Fracture Toughness of Kimachi Sandstone},
 volume = {135},
 year = {2019},
 yomi = {カタオカ, ミナミ and オバラ, ユウゾウ and カタオカ, ミナミ and オバラ, ユウゾウ}
}