Determination of Mode I Fracture Toughness of Rocks Using Wedge Splitting Test

Tae Young Ko; Taek Kon Kim; Dae Hyuk Lee

doi:10.7474/TUS.2019.29.6.523

All Issue

2019 Vol.29, Issue 6 Preview Page Next Page

Original Article

Determination of Mode I Fracture Toughness of Rocks Using Wedge Splitting Test 쐐기 분열 시험을 이용한 암석의 모드 I 파괴인성 측정

31 December 2019. pp. 523-531

PDF XML

Abstract

In the applications of rock mechanics or rock engineering including drill and blast, drilling and mechanical excavation, the fracture toughness is an important factor. Several methods have been proposed to measure the fracture toughness of rocks. In this study, wedge splitting test specimen which is prepared with ease and tested under compression loading was used to obtain mode I fracture toughness of rocks. The equation of stress intensity factor through numerical analysis is proposed from the stress state of crack tip considering both vertical and horizontal loads due to the vertical load acting on the wedge. The validity of the wedge splitting test method was confirmed by comparing the mode I fracture toughness values obtained by the GD and SENB test specimens.

Keywords

Fracture toughness

Stress intensity factor

Rock

Mode I

Finite element method

암석역학이나 암반공학의 여러 활용 분야 중 발파, 천공 및 기계굴착의 경우에는 파괴인성이 중요한 요소이며, 암석의 파괴인성을 측정하기 위한 여러 가지 방법들이 제안되었다. 본 연구에서는 간단히 시험편을 제작할 수 있고, 압축 하중으로 암석의 모드 I 파괴인성을 구할 수 있도록 쐐기 분열 시험편(Wedge Splitting Test Specimen)을 이용하였다. 쐐기의 작용하는 연직하중에 의한 수직 및 수평하중 모두를 고려한 균열선단의 응력상태로부터 수치해석을 통한 응력확대계수의 식을 제안하였다. 쐐기 분열 시험편에 의해 구해진 모드 I 파괴인성값을 GD와 SENB 시험편의 시험 결과와 비교하여 시험법의 타당성을 확인하였다.

키워드

파괴인성

응력확대계수

암석

모드I

유한요소법

References

Chang, S.H. and Lee, C.I., 1999, Measurement of Rock Fracture Toughness under Mode I, II, & Mixed-mode Conditions by Using Disc-typed Specimens, J. of Korean Society for Rock Mech., 9, 315-327.

Donovan, J.G. and Karfakis, M.G., 2004, Adaptation of a Simple Wedge Test for the Rapid Determination of Mode I Fracture Toughness and the Assessment of Relative Fracture Resistance, Int. J. Rock Mech. Min. Sci., 41(4), 695-701.

10.1016/j.ijrmms.2004.01.001

Fowell, R.J., 1995, Suggested Method for Determining Mode I Fracture Toughness Using Cracked Chevron Notched Brazilian Disc (CCNBD) Specimens, Int. J. Rock Mech. Min. Sci. & Geomech. Abstr. 32(1), 57-64.

10.1016/0148-9062(94)00015-U

Ko, T.Y., Kemeny, J., and Moon, H.K., 2008, Determination of the Mode I Fracture Toughness of Rock Using the Compact Tension Specimen and the Effect of Specimen Size and Loading Rate on the Fracture Toughness, Journal of the Korean Society of Mineral and Energy Resources Engineers, 45(3), 243-241.

Kuruppu, M. D., Obara, Y., Ayatollahi, M. R., Chong, K. P., and Funatsu, T., 2014, ISRM-Suggested Method for Determining the Mode I Static Fracture Toughness Using Semi-Circular Bend Specimen, Rock Mech. Rock Eng. 47(1), 267-274.

10.1007/s00603-013-0422-7

Lee, S.E., 2010, Characterization of Microstructures and Fracture Toughness of SR Specimen in Granitic Rocks, J. of Korean Society for Rock Mech., 20(3), 217-224.

Ouchterlony, F., 1988, Suggested Methods Fracture Toughness for Determining the of Rock, Int. J. Rock Mech. Min. Sci. & Geomech. Abstr. 25(2), 71-96.

10.1016/0148-9062(88)91871-2

Singh, R.N. and Pathan, A.G., 1988, Fracture Toughness of Some British Rocks by Diametral Loading of Discs. Min. Sci. Technol. 6, 179-190.

10.1016/S0167-9031(88)90701-3

Srawlwy, J.E., 1976, Wide Range Stress Intensity Factor Expressions for ASTM E399 Standard Fracture Toughness Specimens. Int. J. Fract. Mech. 12, 475-476.

Tada, H., Paris, P. C., and Irwin, G.R., 2000, The Stress Analysis of Cracks Handbook, ASME Press, New York, 677.

10.1115/1.801535

Yang, H.S. and Kim, J.G., 2007, Trends of Research in Fracture Toughness of Rocks, J. of Korean Society for Rock Mech., 17(6), 448-452.

Information

Publisher :Korean Society for Rock Mechanics and Rock Engineering
Publisher(Ko) :한국암반공학회
Journal Title :Tunnel and Underground Space
Journal Title(Ko) :터널과 지하공간
Volume : 29
No :6
Pages :523-531
Received Date : 2019-12-13
Revised Date : 2019-12-23
Accepted Date : 2019-12-23
DOI :https://doi.org/10.7474/TUS.2019.29.6.523

Tunnel and Underground Space ISSN:1225-1275(Print) 2287-1748(Online) 터널과 지하공간

All Issue