資源・素材学会 年次大会

In laboratory measurements of rock properties, the specimen size dependent rock strength has always been an issue. Numerous studies have been conducted to investigate the correlation between specimen size and rock strength under various loading rate in last few decades. In this study, the dynamic uniaxial compression tests of Geochang granite and Kimachi sanstone were carried out to investigate the size-effect on rock dynamic strength. Split Hopkinson pressure bar (SHPB) system was used to load the rock specimens dynamically. Kimachi sandstone and Geochang granite specimens with different diameter and length were prepared. As a result, it has been found that the dynamic uniaxial compression strength of the granite and sandstone have been increased with increasing specimen size. That are coincident with the results revealed recently by some researchers who have showed that the uniaxial compressive strengths of sedimentary rocks significantly increase with increasing specimen diameter up to around 54mm diameter and reduce to with size increment.