HR: 1330h
AN: T43C-04    [Abstracts]
TI: Effects of the Specimen Geometry and Rock Texture on the Fracture Mechanics Properties of Rock Materials
AU: * Baek, H
EM: hwanjo@kangwon.ac.kr
AF: Kangwon National University, 192-1, Hyoja-2-Dong, Chuncheon, 200-701 Korea, Republic of
AU: Choi, S
EM: choigeo@hotmail.com
AF: Kangwon National University, 192-1, Hyoja-2-Dong, Chuncheon, 200-701 Korea, Republic of
AU: Alexandrovna, B E
EM: elena@kangwon.ac.kr
AF: Kangwon National University, 192-1, Hyoja-2-Dong, Chuncheon, 200-701 Korea, Republic of
AB: The application of linear elastic fracture mechanics principles has proven to be an effective approach in rock engineering and geoscience fields. The main objectives of this study are to standardize the mode I fracture toughness values measured by various specimen geometries, and to investigate the effects of the test environments and rock texture on fracture toughness measurement of rock materials. Fracture toughness of rock materials is generally measured by the standard test method suggested by the ISRM. Rock fracture toughness is generally affected by the specimen geometry, like other rock properties, and the toughness values measured employing the attractive NBD, SECRBB, SCB, and MHT specimen geometries are substantially different from those measured by the standard test method. Hence, the main content of this research is to compare the fracture toughness values of several rock types measured by various test methods with the standard values, aiming to standardize the test geometries. It is expected that the direct comparison of rock fracture toughness values measured by different test methods and the selection of proper test geometry will be possible by the result of this research. Many test results have been published concerning the effects of test environments, such as the water content, loading rate, temperature, on the fracture toughness measurement of rock material. However, the effect of the rock texture, that is, the mineralogical composition, bonding characteristics of individual grains, and distribution of microcracks, has not been fully investigated. Theoretical fracture toughness values of typical minerals has been given, but the relationship is still unknown. Moreover, fracture toughness of rock materials is presumably affected by the bonding characteristics. Therefore, another important objectives of this study are to quantify these effects, and to introduce a new method to evaluate the fracture toughness of rock materials from the microstructural observations of rock textures. Also, effects of the rock texture on various rock properties can be verified quantitatively. This will lead to wider application of the fracture mechanics principles to rock engineering fields.
DE: 5100 PHYSICAL PROPERTIES OF ROCKS
DE: 5104 Fracture and flow
DE: 5112 Microstructure
SC: Tectonophysics [T]
MN: 2005 Joint Assembly