Numerical Modelling of the Anisotropic Mechanical Behaviour of Opalinus Clay at the Laboratory-Scale Using FEM/DEM

Lisjak, A.; Tatone, B. S. A.; Grasselli, Giovanni; Vietor, Tim

doi:10.1007/s00603-012-0354-7

Cited by 125 publications

(43 citation statements)

References 52 publications

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“…The anisotropic mechanical behaviors of Opalinus Clay in Brazilian test and compression test have been studied through combined finitediscrete element method (FEM/DEM). 17,18 In this model, a transversely isotropic elastic constitutive law was implemented to describe the elastic response, while DEM algorithms and non-linear fracture mechanics principles were employed to capture rock fracturing. The fracture behavior of slate rock has been modeled in Ref.…”

Section: Introductionmentioning

confidence: 99%

Discrete element modeling of anisotropic rock under Brazilian test conditions

Kang

Kwok

2015

International Journal of Rock Mechanics and Mining Sciences

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Section: Introductionmentioning

confidence: 99%

Discrete element modeling of anisotropic rock under Brazilian test conditions

Kang

Kwok

2015

International Journal of Rock Mechanics and Mining Sciences

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“…Numerical simulations allow analysis of the complete stress and strain field within segmented fault systems (e.g., Bürgmann et al, ; Cowie et al, ; Crider & Pollard, ; Kattenhorn & Pollard, ; Li et al, ; Willemse, ), and so provide additional constraints on the factors that control fault development within anisotropic systems (e.g., Duan & Kwok, ; Duan et al, ; Gudmundsson et al, ; Lisjak et al, ; Misra et al, ; Tong & Yin, ) beyond those gleaned from field observations and physical experiments. For example, DEM modeling of borehole breakouts indicates that material anisotropy exhibits a stronger influence on fracture development near the borehole when the borehole is drilled perpendicular to bedding in simulated shale than when it is drilled parallel to bedding (Duan & Kwok, ).…”

Section: Introductionmentioning

confidence: 99%

Work Optimization Predicts the Evolution of Extensional Step Overs Within Anisotropic Host Rock: Implications for the San Pablo Bay, CA

2017

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Recent geophysical imaging indicates that the Hayward Fault hard links to the Rodgers Creek Fault at 5 m depth within the San Pablo Bay, CA, suggesting that earthquakes may be able to rupture continuously through the fault network. To investigate fault propagation, interaction, and linkage in segmented fault networks, including those within the San Pablo Bay, we simulate the development of two idealized, underlapping faults within an extensional step over at seismogenic depths using work optimization. We test the sensitivity of fault growth to strength anisotropy, material heterogeneities, and initial fault geometry. The optimal faults propagate toward each other until linking with the other fault at its tip and form a single hard‐linked transverse fault. These faults propagate with relatively high propagation power or rate of efficiency gain. Less efficient faults form wider basins and develop with reduced propagation power. Models with initial fault geometries that more closely match the shallowly imaged Hayward and Rodgers Creek faults suggest that the faults link at seismogenic depths if a mapped segment of the Rodgers Creek that extends into the San Pablo Bay is currently inactive. Predictions of average slip rate, slip per earthquake, and earthquake magnitude from these models closely match paleoseismic estimates. The hard linkage of the Hayward and Rodgers Creek faults imaged in the near‐surface, and predicted by these models, increases local seismic hazard by increasing the upper limit of throughgoing earthquakes to M 7.6.

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“…Table I summarizes some of the previous studies aiming at modeling the anisotropic behaviors of rock/rock mass. Lisjak et al [14,15] developed a hybrid continuum/discontinuum approach where the anisotropic strength is captured by incorporating preferentially orientated defects, and the anisotropic modulus is characterized by a transversely isotropic elastic constitutive law. The continuum models have the limitation of representing weak layers explicitly, and thus cannot allow us to investigate the micro-mechanisms controlling the failure process.…”

Section: Simulation Of Inherently Anisotropic Rockmentioning

confidence: 99%

Discrete element method modeling of inherently anisotropic rocks under uniaxial compression loading

Kang

Kwok

Pierce

2015

Num Anal Meth Geomechanics

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SUMMARYA new numerical approach is proposed in this study to model the mechanical behaviors of inherently anisotropic rocks in which the rock matrix is represented as bonded particle model, and the intrinsic anisotropy is imposed by replacing any parallel bonds dipping within a certain angle range with smooth-joint contacts. A series of numerical models with β = 0°, 15°, 30°, 45°, 60°, 75°, and 90°are constructed and tested (β is defined as the angle between the normal of weak layers and the maximum principal stress direction). The effect of smooth-joint parameters on the uniaxial compression strength and Young's modulus is investigated systematically. The simulation results reveal that the normal strength of smooth-joint mainly affects the behaviors at high anisotropy angles (β > 45°), while the shear strength plays an important role at medium anisotropy angles (30°-75°). The normal stiffness controls the mechanical behaviors at low anisotropy angles. The angle range of parallel bonds being replaced plays an important role on defining the degree of anisotropy.Step-by-step procedures for the calibration of micro parameters are recommended. The numerical model is calibrated to reproduce the behaviors of different anisotropic rocks. Detailed analyses are conducted to investigate the brittle failure process by looking at stress-strain behaviors, increment of micro cracks, initiation and propagation of fractures. Most of these responses agree well with previous experimental findings and can provide new insights into the micro mechanisms related to the anisotropic deformation and failure behaviors. The numerical approach is then applied to simulate the stress-induced borehole breakouts in anisotropic rock formations at reduced scale. The effect of rock anisotropy and stress anisotropy can be captured.

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Numerical Modelling of the Anisotropic Mechanical Behaviour of Opalinus Clay at the Laboratory-Scale Using FEM/DEM

Cited by 125 publications

References 52 publications

Discrete element modeling of anisotropic rock under Brazilian test conditions

Discrete element modeling of anisotropic rock under Brazilian test conditions

Work Optimization Predicts the Evolution of Extensional Step Overs Within Anisotropic Host Rock: Implications for the San Pablo Bay, CA

Discrete element method modeling of inherently anisotropic rocks under uniaxial compression loading

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