Crack coalescence in a rock-like material containing two cracks

Wong, Ryc; Chau, Kam Tim

doi:10.1016/s0148-9062(97)00303-3

Cited by 500 publications

(198 citation statements)

References 42 publications

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“…Wong et al [2] gained similar related results showing that 'fish eye' mode coalescence occurs in a critical range of joint coefficients (JC = 0.7) in experiments using plaster modelling material under direct shear tests.…”

Section: Jcmentioning

confidence: 70%

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Numerical Simulation of Shear Behaviour of Non- Persistent Joints under Low and High Normal Loads

Sarfarazi

Ghazvinian

Schubert³

2016

Period. Polytech. Civil Eng.

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In this paper, the effect of rock bridge surface on the shear behavior of planar non-persistent joints under low and high normal loads has been investigated using particle IntroductionThe shear sliding of non-persistent joints are important factors in controlling the mechanical behaviour of rock masses (Einstein [1], Wong [2]). As known, it is difficult and costly to perform field tests to investigate the mechanical behavior of jointed rock masses. Therefore, laboratory tests are commonly conducted to study the influence of joint geometry configurations on the mechanical behavior of jointed blocks [3][4][5][6]. The crack initiation, propagation and coalescence of jointed specimens with less than three open flaws under uniaxial or biaxial compression [7][8][9] have been investigated by many researchers. In these studies, both tensile and shear cracks have been observed [7][8][9][10][11]. Lajtai [12,13], tensile wing cracks were found to first appear at the tips of horizontal joints, followed by the secondary shear cracks propagating towards the opposite joint. Mughieda et al. [14] made a thorough analysis on the Fracture mechanisms of offset rock joints. Gehle and Kutter's [15] investigation on the breakage and shear behaviour of intermittent rock joints under direct shear loading condition showed that joint orientation is an important influential parameter for shear resistance of jointed rock.In laboratory tests, it is difficult to measure the failure mechanism of rock bridge during the loading process. Numerical simulation is another common approach that has been used to investigate the failure mechanism and the mechanical behavior of non-persistent joints using techniques such as the finite element method, realistic failure processing analysis, particle flow code), displacement discontinuity method, boundary element method, distinct element method, and a hybridized indirect boundary element method) [16][17][18][19][20][21][22]. Particle flow code, a distinct element method first induced by Cundall and stark [23], models the mechanical behavior of rock and soils. The materials are envisioned as an assembly comprised of arbitrary spherical particles (in 3D case) or circular disks (in 2D case) in the PFC program. Kulattilake et al [24] were the pioneers in providing a realistic calibration procedure for micro-mechanical parameters of PFC3D for a contact bonded particle model. They also established a jointed rock model by using closed flaws and investigated the relation between micro-parameters and macro-

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Section: Jcmentioning

confidence: 70%

“…The shear sliding of non-persistent joints are important factors in controlling the mechanical behaviour of rock masses (Einstein [1], Wong [2]). As known, it is difficult and costly to perform field tests to investigate the mechanical behavior of jointed rock masses.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Shear Behaviour of Non- Persistent Joints under Low and High Normal Loads

Sarfarazi

Ghazvinian

Schubert³

2016

Period. Polytech. Civil Eng.

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“…Therefore, the micro-cracks coalescence model is consistent with the experimental results obtained by Park and Bobet. Wong and Chau [28] did their researches on the coalescence pattern of two cracks and the strength of material under uniaxial compression. In their experiments, they changed the relative position of two cracks and the surface friction coefficient to observe different patterns of coalescence.…”

Section:  mentioning

confidence: 99%

A constitutive model based on the evolution and coalescence of elliptical micro-cracks for quasi-brittle materials

2012

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Damage and failure of quasi-brittle materials are caused by the evolution and coalescence of micro-cracks. To solve the problem of elliptical micro-crack growth at the elastic deformation stage, a method of complex potential functions is proposed and the effect of the initial orientation on micro-crack growth and deflection is discussed. The critical stress condition for the initial damage is derived according to the criterion of micro-crack growth. Based on energy conservation during wing-crack propagation, a damage constitutive model is developed with the strain criterion created in the condition of micro-crack coalescence. The stress-strain curves of quasi-brittle materials in uniaxial compression obtained based on this model are examined with the experimental results. micro-cracks, damage, evolution, coalescenceCitation:A constitutive model based on the evolution and coalescence of elliptical micro-cracks for quasi-brittle materials.

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“…Bobet and Einstein [7] identified five types of failure patterns from uniaxial compressive tests of gypsum specimens with parallel flaws. Wong and Chau [8] carried out uniaxial compression tests on plaster specimens with two flaws and identified nine types of coalescence patterns. Cao et al [9] investigated the peak uniaxial compressive strength and failure patterns of ubiquitousjoint rock-like specimens by combining similar material testing and numerical simulation.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study on Mechanical Behavior of Parallel Joint Specimens under Compression Shear

Wang

Cao

Chen

et al. 2018

Advances in Civil Engineering

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In order to investigate the influence of the joint on the failure mode, peak shear strength, and shear stress-strain curve of rock mass, the compression shear test loading on the parallel jointed specimens was carried out, and the acoustic emission system was used to monitor the loading process. e joint spacing and joint overlap were varied to alter the relative positions of parallel joints in geometry. Under compression-shear loading, the failure mode of the joint specimen can be classified into four types: coplanar shear failure, shear failure along the joint plane, shear failure along the shear stress plane, and similar integrity shear failure. e joint dip angle has a decisive effect on the failure mode of the specimen. e joint overlap affects the crack development of the specimen but does not change the failure mode of the specimen. e joint spacing can change the failure mode of the specimen. e shear strength of the specimen firstly increases and then decreases with the increase of the dip angle and reaches the maximum at 45°. e shear strength decreases with the increase of the joint overlap and increases with the increase of the joint spacing. e shear stress-displacement curves of different joint inclination samples have differences which mainly reflect in the postrupture stage. From monitoring results of the AE system, the variation regular of the AE count corresponds to the failure mode, and the peak value of the AE count decreases with the increase of joint overlap and increases with the increase of joint spacing.

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Crack coalescence in a rock-like material containing two cracks

Cited by 500 publications

References 42 publications

Numerical Simulation of Shear Behaviour of Non- Persistent Joints under Low and High Normal Loads

Numerical Simulation of Shear Behaviour of Non- Persistent Joints under Low and High Normal Loads

A constitutive model based on the evolution and coalescence of elliptical micro-cracks for quasi-brittle materials

An Experimental Study on Mechanical Behavior of Parallel Joint Specimens under Compression Shear

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