Effect of Confining Pressure on Mode I and Mode II Fracture Toughness of Lushan Sandstone

Document Type : Research Article

Authors

Imam Khomeini international university

Abstract

Rock is a brittle naturally material that is subjected to a variety of environment impacts, such as temperature, confining pressure, humidity and water erosion. Moreover, the effect of confining pressure on rock fracture in most engineering fields has been considered. These include the stability analysis of rock to accumulate atomic waste in underground reservoirs, the hydraulic fracture process for extraction of oil and gas from different layers of the earth and analysis of the stability of underground mines. In this paper, Effect of confining pressure on Mode I and Mode II fracture toughness of Lushan sandstone were investigated. To investigate the effect of confining pressure on mode I and II fracture toughness, was used a Cracked Chevron Notched Brazilian Disc. In this study, the specimens were subjected to a confining pressure of 3, 5, 7and 10 MPa. In this experiments, specimens of Lushan sandstone is studied specimens. The results show that, with increasing confining pressure, mode I and II fracture toughness of sandstone increases linearly and nonlinearly respectively.

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[1]F. Erdogan, G. Sih, On the crack extension in plates under plane loading and transverse shear, 1963.
[2]M. Hussain, S. Pu, J. Underwood, Strain energy release rate for a crack under combined mode I and mode II, in:  Fracture analysis: Proceedings of the 1973 national symposium on fracture mechanics, part II, ASTM International, 1974.
[3]G.C. Sih, Strain-energy-density factor applied to mixed mode crack problems, International Journal of fracture, 10(3) (1974) 305-321.
[4]S.-H. Chang, C.-I. Lee, S. Jeon, Measurement of rock fracture toughness under modes I and II and mixed-mode conditions by using disc-type specimens, Engineering geology, 66(1-2) (2002) 79-97.
[5]R. Schmidt, C. Huddle, Effect of confining pressure on fracture toughness of Indiana limestone, in:  International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Elsevier, (1977) 289-293.
[6]A. Abou Sayed, An experimental technique for mneasurig the fracture toughness of rocks under downhole stress condition, 1978.
[7]W. Müller, Brittle crack growth in rocks, pure and applied geophysics, 124(4-5) (1986) 693-709.
[8]N. Al-Shayea, K. Khan, S. Abduljauwad, Effects of confining pressure and temperature on mixed-mode (I–
II) fracture toughness of a limestone rock, International Journal of Rock Mechanics and Mining Sciences, 37(4) (2000) 629-643.
[9]T. Backers, O. Stephansson, E. Rybacki, Rock fracture toughness testing in Mode II—punch-through shear test, International Journal of Rock Mechanics and Mining Sciences, 39(6) (2002) 755-769.
[10]T. Funatsu, M. Seto, H. Shimada, K. Matsui, M. Kuruppu, Combined effects of increasing temperature and confining pressure on the fracture toughness of clay bearing rocks, International Journal of Rock Mechanics and Mining Sciences, 41(6) (2004) 927-938.
[11]H. Wu, J. Kemeny, S. Wu, Experimental and numerical investigation of the punch-through shear test for mode II fracture toughness determination in rock, Engineering Fracture Mechanics, 184 (2017) 59-74.
[12]S.H. Chang, C.I. Lee, S. Jeon, Measurement of rock fracture toughness under modes I and II and mixed-mode conditions by using disc-type specimens, Engineering geology, 66(1-2) (2002) 79-97.
[13]M. Aliha, M. Ayatollahi, Rock fracture toughness study using cracked chevron notched Brazilian disc specimen under pure modes I and II loading–A statistical approach, Theoretical and Applied Fracture Mechanics, 69 (2014) 17-25.
[14]R. Fowell, J. Hudson, C. Xu, X. Zhao, Suggested method for determining mode I fracture toughness using cracked chevron notched Brazilian disc (CCNBD) specimens, in:  International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, 1995.
[15]R. Fowell, C. Xu, P. Dowd, An update on the fracture toughness testing methods related to the cracked chevronnotched Brazilian disk (CCNBD) specimen, pure and applied geophysics, 163(5-6) (2006) 1047-1057.
[16]A.W. Hatheway, The complete ISRM suggested methods for rock characterization, testing and monitoring; 1974– 2006, in, Association of Environmental & Engineering Geologists, 2009.