• The Journal of Engineering Geology
• /
• v.16 no.1 s.47
• /
• pp.1-14
• /
• 2006

Various measurements were carried out to estimate the modulus of deformation in two dominant rock types in Korea: granite and gneiss. Four most commonly used methods were utilized: Goodman jack tests, PS well logging, laboratory ultrasonic tests and laboratory uniaxial loading tests. Laboratory static and dynamic Young's moduli depend on the magnitude of the applied axial stress, range of Sequency used for measurement and the loading/unloading condition. As the laboratory measurement condition approaches to that in situ, the resultant moduli also appear to be comparable to that in situ. This suggests that the simulation of in situ stress condition is important when the modulus of rock is determined in the laboratory Dynamic Young's modulus is generally higher than static Young's modulus because of (micro)crack behavior in response to the stress, different range of frequency used for measurements, and the effect of the amplitude of deformation. Understanding of the relations in moduli from different measurement methods will help estimate appropriate in situ values.

• Explosives and Blasting
• /
• v.25 no.1
• /
• pp.15-29
• /
• 2007

In situ and laboratory tests were carried out for investigating the Excavation Disturbed Zone(EDZ) generated from blasting at the KAERI Underground Research Tunnel(KURT), which is for the researches related to High-level radioactive waste disposal program. It was found that the EDZ was generated more than In from the laboratory rock tests and in situ experiments. RQD of the rock mass within $0{\sim}2(m)$, where the blasting impact was significant, was 17% lower than in the deeper zones without a serious blasting impact. It was also estimated that the deformability of rock mass was reduced about 40% after the blasting.