Macro-micro experimental study of rock static and dynamic fracture toughness

MAN Ke; LIU Xiaoli; SONG Zhifei; GUO Zhanfeng; LIU Zongxu; YU Yunhe

doi:10.16511/j.cnki.qhdxxb.2021.26.018

PDF(15109 KB)

Journal of Tsinghua University(Science and Technology) ›› 2021, Vol. 61 ›› Issue (8) : 799-808. DOI: 10.16511/j.cnki.qhdxxb.2021.26.018

Experimental Research

Macro-micro experimental study of rock static and dynamic fracture toughness

{{article.zuoZhe_EN}}

Author information +

History +

Abstract

The notched semi-circle bend (NSCB) specimen and fracture toughness test method was used to measure the static and dynamic fracture toughness of Beijing Fangshan granite samples. The results showed the dynamic fracture toughness is generally 1.3~2.6 times the static fracture toughness for medium and high strain rates. The surface morphologies of the damaged rock samples were then characterized using SEM and a laser confocal microscope for three-dimensional reconstructions of the fractures and surface roughnesses. The static and dynamic fracture modes were both mode I crack tensile failures. The difference between the dynamic and static crack growth was that the stress wave in the dynamic tests reflected back and forth at the internal interface of rock sample which induced micro-cracks and accelerated the convergence and penetration of existing and new cracks. The crack propagation had acceleration and deceleration stages with the changes in the rock crack propagation speed consistent with the relative height of the reconstructed three-dimensional rock surface morphology, which also corresponded to the rock surface roughness variations. The key difference between the static and dynamic behavior is that the rate effect (inertia effect) during dynamic loading tends to counteract the structural effects of the physical and geometric properties of the rock material itself.

Key words

static fracture toughness / dynamic fracture toughness / NSCB / surface morphology / structural effect / dynamic rate effect

Cite this article

EndNote

Ris (Procite)

Bibtex

Download Citations

MAN Ke, LIU Xiaoli, SONG Zhifei, GUO Zhanfeng, LIU Zongxu, YU Yunhe. Macro-micro experimental study of rock static and dynamic fracture toughness[J]. Journal of Tsinghua University(Science and Technology). 2021, 61(8): 799-808 https://doi.org/10.16511/j.cnki.qhdxxb.2021.26.018

References

[1] LIU K, ZHAO J, WU G, et al. Dynamic strength and failure modes of sandstone under biaxial compression[J]. International Journal of Rock Mechanics and Mining Sciences, 2020, 128:104260.
[2] ZHANG L W, ZHANG X Y, WU J, et al. Rockburst prediction model based on comprehensive weight and extension methods and its engineering application[J]. Bulletin of Engineering Geology and the Environment, 2020, 79(9):4891-4903.
[3] OWEN D M, ZHUANG S, ROSAKIS A J, et al. Experimental determination of dynamic crack initiation and propagation fracture toughness in thin aluminum sheets[J]. International Journal of Fracture, 1998, 90(1):153-174.
[4] ZHANG Z X, KOU S Q, YU J, et al. Effects of loading rate on rock fracture[J]. International Journal of Rock Mechanics and Mining Sciences, 1999, 36(5):597-611.
[5] ZHANG Z X, KOU S Q, JIANG L G, et al. Effects of loading rate on rock fracture:Fracture characteristics and energy partitioning[J]. International Journal of Rock Mechanics and Mining Sciences, 2000, 37(5):745-762.
[6] SONG B, CHEN W. Energy for specimen deformation in a split Hopkinson pressure bar experiment[J]. Experimental Mechanics, 2006, 46(3):407-410.
[7] IQBAL M J, MOHANTY B. Experimental calibration of stress intensity factors of the ISRM suggested cracked chevron-notched Brazilian disc specimen used for determination of mode-I fracture toughness[J]. International Journal of Rock Mechanics and Mining Sciences, 2006, 43(8):1270-1276.
[8] FREW D J, FORRESTAL M J, CHEN W. Pulse shaping techniques for testing brittle materials with a split Hopkinson pressure bar[J]. Experimental Mechanics, 2002, 42(1):93-106.
[9] NASSERI M H B, MOHANTY B. Fracture toughness anisotropy in granitic rocks[J]. International Journal of Rock Mechanics and Mining Sciences, 2008, 45(2):167-193.
[10] GU H L, TAO M, LI X B, et al. Dynamic response and meso-deterioration mechanism of water-saturated sandstone under different porosities[J]. Measurement, 2021, 167:108275.
[11] ZHOU X P, WANG L F, SHOU Y D. Understanding the fracture mechanism of ring Brazilian discspecimens by the phase field method[J]. International Journal of Fracture, 2020, 226(1):17-43.
[12] ALIHA M R M, AYATOLLAHI M R. Two-parameter fracture analysis of SCB rock specimen under mixed mode loading[J]. Engineering Fracture Mechanics, 2013, 103:115-123.
[13] ALIHA M R M, MAHDAVI E, AYATOLLAHI M R. Statistical analysis of rock fracture toughness data obtained from different chevron notched and straight cracked mode I specimens[J]. Rock Mechanics and Rock Engineering, 2018, 51(7):2095-2114.
[14] ALIHA M R M, BAHMANI A. Rock fracture toughness study under mixed mode I/III loading[J]. Rock Mechanics and Rock Engineering, 2017, 50(7):1739-1751.
[15] ALIHA M R M, HOSSEINPOUR G R, AYATOLLAHI M R. Application of cracked triangular specimen subjected to three-point bending for investigating fracture behavior of rock materials[J]. Rock Mechanics and Rock Engineering, 2013, 46(5):1023-1034.
[16] ALIHA M R M, AYATOLLAHI M R, AKBARDOOST J. Typical upper bound-lower bound mixed mode fracture resistance envelopes for rock material[J]. Rock Mechanics and Rock Engineering, 2012, 45(1):65-74.
[17] CHEN C S, PAN E N, AMADEI B. Fracture mechanics analysis of cracked discs of anisotropic rock using the boundary element method[J]. International Journal of Rock Mechanics and Mining Sciences, 1998, 35(2):195-218.
[18] NASSERI M H B, MOHANTY B, YOUNG R P. Fracture toughness measurements and acoustic emission activity in brittle rocks[J]. Pure and Applied Geophysics, 2006, 163(5-6):917-945.
[19] CHEN R, XIA K, DAI F, et al. Determination of dynamic fracture parameters using a semi-circular bend technique in split Hopkinson pressure bar testing[J]. Engineering Fracture Mechanics, 2009, 76(9):1268-1276.
[20] ZHANG Q B, ZHAO J. Effect of loading rate on fracture toughness and failure micromechanisms in marble[J]. Engineering Fracture Mechanics, 2013, 102:288-309.
[21] ZHANG Q B, ZHAO J. Determination of mechanical properties and full-field strain measurements of rock material under dynamic loads[J]. International Journal of Rock Mechanics and Mining Sciences, 2013, 60:423-439.
[22] ZHOU X P, QIAN Q H, YANG H Q. Effect of loading rate on fracture characteristics of rock[J]. Journal of Central South University of Technology, 2010, 17(1):150-155.
[23] FOWELL R J. Suggested method for determining mode I fracture toughness using cracked chevron notched Brazilian disc (CCNBD) specimens[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1995, 32(1):57-64.
[24] Freund L B. Dynamic fracture mechanics[M]. Cambridge:Cambridge University Press, 1998.
[25] AYATOLLAHI M R. Response of an orthotropic half-plane subjected to transient anti-plane loading with multiple edge cracks[J]. Journal of Physics:Conference Series, 2017, 843:012015.