시험편 형상에 따른 암석의 파괴인성 측정치 변화
Effects of the Specimen Geometry on Rock Fracture Toughness
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초록
일반적으로 파괴인성의 측정치는 다른 물성들과 마찬가지로 시험조건에 따라 상당한 차이를 나타내며, 암석에 내재하는 불균질성으로 인하여 자료의 분산이 심한 편이다. 본 연구에서는 포천 화강암과 모르타르 시료를 대상으로 ISRM에서 제시한 표준시험방법인 CB을 포함하여, SCB, NBD, SECRBB 시험법을 이용하여 Mode I에서의 파괴인성을 측정함으로써 시험편 형상에 따른 파괴인성 측정치의 변화를 살펴보았으며, 모르타르 시험편에 대해서는 ASTM에 표준시험방법으로 제시되어 있는 삼점굴곡시험을 실시하였다. NBD 시험편은 측정치가 CB 시험편의 경우와 비교적 근접하고 시험편의 크기도 가장 작다. 따라서, 암석의 불균질성을 고려할 때, 다수의 시험편으로부터 구한 평균치의 획득에 유리할 것으로 판단된다.
Abstract
The rock fracture toughness, like other rock properties, generally depends on the specimen geometry and test results substantially scatter presumably due to inhomogeneity of rock materials. In this study, the mode I fracture toughness of the Pocheon granite and mortar specimens were measured using the SCB, NBD, SECRBB and CB specimens. For mortar specimens the three-point bending test, a standard test method suggested by ASTM, was also employed, and variations in the fracture toughness values measured by different specimen geometries were compared. It was found that the NBD specimen, which required much smaller specimens, produced fracture toughness values close to those measured by the CB specimen. Hence, considering inhomogeneity and anisotropy of rock materials, it would be more practical to employ NBD specimen type than the CB type, to obtain representative fracture toughness value from ample specimens.
참고문헌 (17)
- "시험편의 형상 및 치수가 암석의 파괴인성 측정에 미치는 영향에 관한 연구", pp.49~59 (1994)
- "ISRM Suggested Method에 의거한 파괴인성에 관한 연구", pp.83~92 (1993)
- "인장, 전단 및 혼합모드에서 디스크 시험편을 이용한 암석의 파괴인성 측정에 관한 연구", 9(4), pp.315~327 (1999)
- "Standard test methods for plane-strain fracture toughness of metallic materials." (1978)
- "Evaluation of fracture mechanics properties and microstructural observations of rock fractures Dept. of Civil Engineering The University of Texas at Austin", pp.200~ (1994)
- "Dept. of Civil Engineering The University of Wyoming.", (nlinear fracture mechanics using semi-circular specimens and tension softening behavior), pp.269~
- "Plane strain fracture toughness testing of high strength metallic materials" (1966)
- "Experimentally determined stress-intensity factor for single edge round bars loaded in bending", 16, pp.249~257 (1976)
- "New specimen for fracture toughness determination for rock and other materials International Journal of Fracture", 26, pp.59~62 (1984)
- "The cracked chevron notched Brazilian disc test-Geometrical consideration for practical rock fracture toughness measurement", 30, pp.821~824 (1993)
- "Suggested method for determining mode I fracture toughness using cracked chevron notched Brazialian disc (CCNBD) specimen", 32(1), pp.57~64 (1995)
- "The phenomenon of rupture and flow in solids Philosophical Transactions of the Royal Society of London", 221, pp.163~198 (1920)
- "Analysis of stresses and strains near the end of a crack traversing a plate Journal of Applied Mechanics", 24, pp.361~364 (1957)
- "ISRM commission on testing methods Suggestive methods for determining the fracture toughness of rock", 25, pp.71~96 (1988)
- "Stress-intensity factors and crack-opening displacements for round compact specimens International Journal of Fracture", 17, pp.567~578 (1981)
- "Extension of the compliance and stress intensity formulas for the single edge crack round bars in bending Fracture mechanics methods for ceramics", pp.237~256 (1981)
- "Fracture toughness determination of brittle materials using small to extremely small specimens", 13, pp.955~961 (1980)