Abstract
Fracture coalescence is a critical phenomenon for creating large, inter-connected fractures from smaller cracks, affecting fracture network flow and seismic energy release potential. In this paper, simulations are performed to model fracture coalescence processes in granite specimens with pre-existing flaws. These simulations utilize an in-house implementation of the combined finite–discrete element method (FDEM) known as the hybrid optimization software suite (HOSS). The pre-existing flaws within the specimens follow two geometric patterns: (1) a single-flaw oriented at different angles with respect to the loading direction, and (2) two flaws, where the primary flaw is oriented perpendicular to the loading direction and the secondary flaw is oriented at different angles. The simulations provide insight into the evolution of tensile and shear fracture behavior as a function of time. The single-flaw simulations accurately reproduce experimentally measured peak stresses as a function of flaw inclination angle. Both the single- and double-flaw simulations exhibit a linear increase in strength with increasing flaw angle while the double-flaw specimens are systematically weaker than the single-flaw specimens.
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Abbreviations
- BD:
-
Brazilian disk
- BEM:
-
Boundary element method
- DEM:
-
Discrete element method
- FDEM:
-
Finite–discrete element method
- HOSS:
-
Hybrid optimization software suite
- UCS:
-
Uniaxial compressive strength
- C :
-
Damping matrix
- M :
-
Lumped mass matrix
- f :
-
Equivalent force vector
- x :
-
Displacement vector
- c :
-
Cohesion
- D :
-
Damage
- G I :
-
Mode I fracture energy
- G II :
-
Mode II fracture energy
- \(\alpha\) :
-
Angle of inclination
- \({\delta ^{\text{e}}}\) :
-
Elastic threshold relative displacement
- \(\delta _{{\text{n}}}^{{\text{e}}}\) :
-
Elastic threshold normal relative displacement
- \(\delta _{{\text{t}}}^{{\text{e}}}\) :
-
Elastic threshold tangential relative displacement
- \({\delta ^{\rm{max} }}\) :
-
Maximum relative displacement
- \(\delta _{{\text{n}}}^{{\rm{max} }}\) :
-
Maximum normal relative displacement
- \(\delta _{{\text{t}}}^{{\rm{max} }}\) :
-
Maximum tangential relative displacement
- \({\mu _{\text{s}}}\) :
-
Coefficient of static friction
- \({\sigma _{\text{n}}}\) :
-
Normal stress
- \({\sigma _{\text{t}}}\) :
-
Tangential stress
- \({\sigma ^{\rm{max} }}\) :
-
Maximum stress
- \(\sigma _{{\text{n}}}^{{\rm{max} }}\) :
-
Maximum normal stress
- \(\sigma _{{\text{t}}}^{{\rm{max} }}\) :
-
Maximum tangential stress
- \({\phi _{\text{c}}}\) :
-
Internal angle of friction
References
Backers T (2004) Fracture toughness determination and micromechanics of rock under mode I and mode II loading. Dissertation, University of Postdam
Bobet A (1997) Fracture coalescence in rock materials: experimental observations and numerical predictions. Dissertation, Massachusetts Institute of Technology
Bobet A (2000) The initiation of secondary cracks in compression. Eng Fract Mech 66:187–219. https://doi.org/10.1016/S0013-7944(00)00009-6
Bobet A, Einstein HH (1998a) Fracture coalescence in rock-type materials under uniaxial and biaxial compression. Int J Rock Mech Min Sci 35:863–888. https://doi.org/10.1016/S0148-9062(98)00005-9
Bobet A, Einstein HH (1998b) Numerical modeling of fracture coalescence in a model rock material. Int J Fract 92:221–252. https://doi.org/10.1023/A:1007460316400
Carey JW, Lei Z, Rougier E, Mori H, Viswanathan H (2015) Fracture-permeability behavior of shale. J Unconv Oil Gas Resour 11:27–43. https://doi.org/10.1016/j.juogr.2015.04.003
Elmo D, Stead D (2010) An integrated numerical modelling-discrete fracture network approach applied to the characterisation of rock mass strength of naturally fractured pillars. Rock Mech Rock Eng 43:3–19. https://doi.org/10.1007/s00603-009-0027-3
Frash LP, Carey JW, Lei Z, Rougier E, Ickes T, Viswanathan HS (2016) High-stress triaxial direct-shear of Utica shale and in situ X-ray microtomography with permeability measurement. J Geophys Res 121:5493–5508. https://doi.org/10.1002/2016JB012850
Frash LP, Carey JW, Ickes T, Viswanathan HS (2017) Caprock integrity susceptibility to permeable fracture creation. Int J Greenh Gas Control 64:60–72. https://doi.org/10.1016/j.ijggc.2017.06.010
Gingold RA, Monaghan JJ (1977) Smoothed particle hydrodynamics: theory and application to non-spherical stars. Mon Not R Astron Soc 181:375–389
Gonçalves Da Silva B, Einstein HH (2013) Modeling of crack initiation, propagation and coalescence in rocks. Int J Fract 182:167–186. https://doi.org/10.1007/s10704-013-9866-8
Gudmundsson A (2011) Rock fractures in geological processes. Cambridge University Press, New York. https://doi.org/10.1017/CBO9780511975684
Haeri H, Shahriar K, Marji MF, Moarefvand P (2014) Experimental and numerical study of crack propagation and coalescence in pre-cracked rock-like disks. Int J Rock Mech Min Sci 67:20–28. https://doi.org/10.1016/j.ijrmms.2014.01.008
Hoek E, Martin CD (2014) Fracture initiation and propagation in intact rock—a review. J Rock Mech Geotech Eng 6:287–300. https://doi.org/10.1016/j.jrmge.2014.06.001
Horii H, Nemat-Nasser S (1985) Compression-induced microcrack growth in brittle solids: axial splitting and shear failure. J Geophys Res 90:3105. https://doi.org/10.1029/JB090iB04p03105
Jeong SS, Nakamura K, Yoshioka S, Obara Y, Kataoka M (2017) Fracture toughness of granite measured using micro to macro scale specimens. Procedia Eng 191:761–767
Jing L, Hudson JA (2002) Numerical methods in rock mechanics. Int J Rock Mech Min Sci 39:409–427
Lee H, Jeon S (2011) An experimental and numerical study of fracture coalescence in pre-cracked specimens under uniaxial compression. Int J Solids Struct 48:979–999. https://doi.org/10.1016/j.ijsolstr.2010.12.001
Lisjak A, Grasselli G (2010) Rock impact modelling using FEM/DEM. In: Proceedings of the 5th international conference on discrete element method, London, England
Lisjak A, Grasselli G (2014) A review of discrete modeling techniques for fracturing processes in discontinuous rock masses. J Rock Mech Geotech Eng 6:301–314. https://doi.org/10.1016/j.jrmge.2013.12.007
Ma GW, Wang QS, Yi XW, Wang XJ (2014) A modified SPH method for dynamic failure simulation of heterogeneous material. Math Probl Eng. https://doi.org/10.1155/2014/808359
Munjiza A (2004) The combined finite-discrete element method. Wiley, Chichester. https://doi.org/10.1002/0470020180
Munjiza A, Andrews KRF, White JK (1999) Combined single and smeared crack model in combined finite-discrete element analysis. Int J Numer Methods Eng 44:41–57
Munjiza A, Knight EE, Rougier E (2011) Computational mechanics of discontinua. Wiley, Chichester. https://doi.org/10.1002/9781119971160
Munjiza A, Rougier E, Knight EE (2015) Large strain finite element method: a practical course. Wiley, Chichester
Park CH, Bobet A (2009) Crack coalescence in specimens with open and closed flaws: a comparison. Int J Rock Mech Min Sci 46:819–829. https://doi.org/10.1016/j.ijrmms.2009.02.006
Park CH, Bobet A (2010) Crack initiation, propagation and coalescence from frictional flaws in uniaxial compression. Eng Fract Mech 77:2727–2748. https://doi.org/10.1016/j.engfracmech.2010.06.027
Paterson MS, Wong T (2005) Experimental rock deformation—the brittle field. Springer, Berlin. https://doi.org/10.1007/b137431
Potyondy DO, Cundall PA (2004) A bonded-particle model for rock. Int J Rock Mech Min Sci 41:1329–1364
Rougier E, Knight EE, Broome ST, Sussman AJ, Munjiza A (2014) Validation of a three-dimensional Finite-Discrete Element Method using experimental results of the Split Hopkinson pressure bar test. Int J Rock Mech Min Sci 70:101–108. https://doi.org/10.1016/j.ijrmms.2014.03.011
Shen B (1995) The mechanism of fracture coalescence in compression-experimental study and numerical simulation. Eng Fract Mech 51:73–85. https://doi.org/10.1016/0013-7944(94)00201-R
Tang CA, Kou SQ (1998) Crack propagation and coalescence in brittle materials under compression. Eng Fract Mech 61:311–324. https://doi.org/10.1016/S0013-7944(98)00067-8
Tang CA, Lin P, Wong RHC, Chau KT (2001) Analysis of crack coalescence in rock-like materials containing three flaws—part II: numerical approach. Int J Rock Mech Min Sci 38:925–939. https://doi.org/10.1016/S1365-1609(01)00065-X
Tatone BSA, Grasselli G (2015) A calibration procedure for two-dimensional laboratory-scale hybrid finite-discrete element simulations. Int J Rock Mech Min Sci 75:56–72. https://doi.org/10.1016/j.ijrmms.2015.01.011
Tatone B, Lisjak A, Mahabadi OK, Grasselli G, Donnelly CR (2010) Evaluation of the combined finite element-discrete element method for the assessment of gravity dam stability. In: Proceedings of the 2010 Canadian dam association conference, Niagara Falls, Ontario, Canada. https://doi.org/10.13140/2.1.1509.7285
Vásárhelyi B (2006) Review article: analysing the crack coalescence in brittle rock materials. Acta Geodaetica et Geophysica Hungarica 41:181–198. https://doi.org/10.1556/AGeod.41.2006.2.4
Vásárhelyi B, Bobet A (2000) Modeling of crack initiation, propagation and coalescence in uniaxial compression. Rock Mech Rock Eng 33:119–139. https://doi.org/10.1007/s006030050038
Wong NY (2008) Crack coalescence in molded gypsum and Carrara marble. Dissertation, Massachusetts Institute of Technology
Wong RHC, Chau KT (1998) Crack coalescence in a rock-like material containing two cracks. Int J Rock Mech Min Sci 35:147–164. https://doi.org/10.1016/S0148-9062(97)00303-3
Wong LNY, Einstein HH (2009) Crack coalescence in molded gypsum and Carrara marble: part 1. Macroscopic observations and interpretation. Rock Mech Rock Eng 42:475–511. https://doi.org/10.1007/s00603-008-0002-4
Yang SQ, Yang DS, Jing HW, Li YH, Wang SY (2012) An experimental study of the fracture coalescence behaviour of brittle sandstone specimens containing three fissures. Rock Mech Rock Eng 45:563–582. https://doi.org/10.1007/s00603-011-0206-x
Yin P, Wong RHC, Chau KT (2014) Coalescence of two parallel pre-existing surface cracks in granite. Int J Rock Mech Min Sci 68:66–84. https://doi.org/10.1016/j.ijrmms.2014.02.011
Zhang X-P, Wong LNY (2013) Crack initiation, propagation and coalescence in rock-like material containing two flaws: a numerical study based on bonded-particle model approach. Rock Mech Rock Eng 46:1001–1021. https://doi.org/10.1007/s00603-012-0323-1
Acknowledgements
Support provided by the Department of Energy (DOE) Basic Energy Sciences program (DE-AC52-06NA25396). The authors would like to thank the LANL Institutional Computing program for their support in generating data used in this work.
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Euser, B., Rougier, E., Lei, Z. et al. Simulation of Fracture Coalescence in Granite via the Combined Finite–Discrete Element Method. Rock Mech Rock Eng 52, 3213–3227 (2019). https://doi.org/10.1007/s00603-019-01773-0
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DOI: https://doi.org/10.1007/s00603-019-01773-0