Micromechanical modeling of cracking and failure in brittle rocks

Hazzard, Jim; Young, R. P.; Maxwell, Shawn

doi:10.1029/2000jb900085

Cited by 246 publications

(124 citation statements)

References 30 publications

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“…This is the main merit of the CD method which we exploit in the present studies prior to its application to more complex geological situations. In this respect, while the present study is entirely devoted to the rheology of rigid cohesionless particle sets, let us observe that both cohesion and contact deformation, as observed in rocks [e.g., Hazzard et al, 2000], can be modeled in the spirit of the CD method . For example, the tensile contact strength can be introduced by specifying a negative (according to our sign conventions) threshold for normal contact forces or impulsions.…”

Section: Contact Dynamics Methodsmentioning

confidence: 99%

Rheology, force transmission, and shear instabilities in frictional granular media from biaxial numerical tests using the contact dynamics method

et al. 2005

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[1] By means of the contact dynamics discrete element method, we investigate the quasistatic behavior of granular media composed of rigid frictional particles. Eluding specific modeling of the contact rheology, this method is suitable for numerical simulation of the plastic deformations of granular materials. We studied the macroscopic stress-strain and volume-change behavior, as well as force transmission and shear instabilities, in a two-dimensional biaxial geometry for dense samples composed of 5000 rigid disks. The peak and residual strengths and shear bands were analyzed by varying the confining pressure and the coefficient of friction between particles. The results are consistent with well-known features of the plasticity of noncohesive granular media. The mechanical behavior is rigid-plastic governed by a Mohr-Coulomb yield criterion and showing strain hardening and softening. Conjugated shear bands characterize plastic failure. The volumetric strain is globally dilatant with considerable expansion observed along shear bands. The macroscopic coefficient of friction, determined from peak and residual strengths, increases nonlinearly and saturates to a constant value as a function of contact friction. The strong force chains are mostly parallel to the major principal stress axis, yet deviations are observed near the shear bands. These chains are often composed of particles that are larger than the average. The deviatoric stress shows small fluctuations often in the form of rapid falls that are correlated with tiny contractional events. This behavior is interpreted in terms of the propagation of dynamic shear instabilities along the shear bands, in close analogy with stick-slip behavior.Citation: Taboada, A., K.-J. Chang, F. Radjaï, and F. Bouchette (2005), Rheology, force transmission, and shear instabilities in frictional granular media from biaxial numerical tests using the contact dynamics method,

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Section: Contact Dynamics Methodsmentioning

confidence: 99%

Rheology, force transmission, and shear instabilities in frictional granular media from biaxial numerical tests using the contact dynamics method

et al. 2005

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“…Particle Flow Code. e particle flow code (PFC) is an effective method to study the macromechanics problems of an analytic object (including construction and rock mass) at the microlevel [22][23][24][25][26], which has been widely applied in simulation tests of uniaxial compression, biaxial compression, and triaxial compression for the rock specimen [19,[27][28][29][30]. ere are two bonding models in PFC 2D software, including the contact bond model and parallel bond model [26][27][28][29][30].…”

Section: Uniaxial Compression Model For Granitementioning

confidence: 99%

Simulation Study on Strength and Failure Characteristics for Granite with a Set of Cross‐Joints of Different Lengths

Yin

Chen

Liu

et al. 2018

Advances in Civil Engineering

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e strength and failure characteristics for granite specimen with a set of cross-joints of different lengths were studied using PFC 2D software. e results show that when the included angle of α between the main joint and loading direction is 30°or 45°, no matter what the included angle of β between main and secondary joints is, the main joint controls crack propagation and failure of granite specimen, which occurs the shear failure propagating from main joint tips, and the corresponding uniaxial compressive strength is low. Meanwhile, the secondary joint is the key joint for crack propagation and failure at α of 0°and 90°except when β is 90°. e granite specimen occurs the shear failure propagating from secondary joint tips. And, the shear failure crossing upper tips of main and secondary joints is found at α of 0°or 90°and β of 90°. eir uniaxial compressive strengths are large. Also, the combined actions of main and secondary joints determine crack propagation and failure at α of 60°except when β is 90°. e granite specimen occurs the hybrid failure, including shear failure propagating from main joint tips and tensile failure propagating from main and secondary joints center or secondary joint tips. And, when α is 60°and β is 90°, the granite specimen occurs the shear failure along secondary joint plane direction, and its uniaxial compressive strength is small. Generally, when α or β is a fixed value, the uniaxial compressive strength firstly decreases and then increases with the increase of β or α. Additionally, when α is 60°and β > 45°, the uniaxial compressive strength represents a decreasing trend. e uniaxial compressive strength at α and β between 30°a nd 60°is generally small. Finally, the microdisplacement field distributions of granite specimen were discussed.

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“…[6] This work investigates hydromechanical behavior of porous media using a DEM technique for solid mechanics first presented by Cundall [1971] and Cundall and Strack [1979], which has successfully approximated the behavior of noncohesive, granular systems under low stress conditions [Cundall et al, 1982;Cleary and Campbell, 1993;Campbell et al, 1995;Morgan, 1999;Morgan and Boettcher, 1999], and lithified sedimentary rocks [Bruno and Nelson, 1991;Potyondy et al, 1996;Hazzard et al, 2000;Boutt and McPherson, 2002]. Extensive comparisons of the DEM to theoretical, numerical, and experimental systems have been performed [Pande et al, 1990].…”

Section: Modeling Approachmentioning

confidence: 99%

Direct simulation of fluid‐solid mechanics in porous media using the discrete element and lattice‐Boltzmann methods

Boutt¹,

Cook²,

McPherson³

et al. 2007

J. Geophys. Res.

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[1] A detailed understanding of the coupling between fluid and solid mechanics is important for understanding many processes in Earth sciences. Numerical models are a popular means for exploring these processes, but most models do not adequately handle all aspects of this coupling. This paper presents the application of a micromechanically based fluid-solid coupling scheme, lattice-Boltzmann discrete element method (LBDEM), for porous media simulation. The LBDEM approach couples the lattice-Boltzmann method for fluid mechanics and a discrete element method for solid mechanics. At the heart of this coupling is a previously developed boundary condition that has never been applied to coupled fluid-solid mechanics in porous media. Quantitative comparisons of model results to a one-dimensional analytical solution for fluid flow in a slightly deformable medium indicate a good match to the predicted continuum-scale fluid diffusion-like profile. Coupling of the numerical formulation is demonstrated through simulation of porous medium consolidation with the model capturing poroelastic behavior, such as the coupling between applied stress and fluid pressure rise. Finally, the LBDEM model is used to simulate the genesis and propagation of natural hydraulic fractures. The model provides insight into the relationship between fluid flow and propagation of fractures in strongly coupled systems. The LBDEM model captures the dominant dynamics of fluid-solid micromechanics of hydraulic fracturing and classes of problems that involve strongly coupled fluid-solid behavior.

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Micromechanical modeling of cracking and failure in brittle rocks

Cited by 246 publications

References 30 publications

Rheology, force transmission, and shear instabilities in frictional granular media from biaxial numerical tests using the contact dynamics method

Rheology, force transmission, and shear instabilities in frictional granular media from biaxial numerical tests using the contact dynamics method

Simulation Study on Strength and Failure Characteristics for Granite with a Set of Cross‐Joints of Different Lengths

Direct simulation of fluid‐solid mechanics in porous media using the discrete element and lattice‐Boltzmann methods

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