A study of brittle rock fracture in laboratory compression experiments

Wawersik, W.R.; Fairhurst, C.

doi:10.1016/0148-9062(70)90007-0

Cited by 703 publications

(261 citation statements)

References 8 publications

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“…As shown in some theories in rock mechanics, there would be no catastrophic rupture under absolutely stiff loading. In fact, under certain conditions, catastrophic rupture may be triggered by damage localization even in an absolutely stiff testing machine [42][43][44][45]. However, it should be noted that the testing apparatus used in the experiments is elastic (to simulate most practical cases) with a stiffness of about 60 kN/mm, which is about 1/10 of the intact sample stiffness; thus, catastrophic rupture appears under certain conditions.…”

Section: Characteristics Of Responsesmentioning

confidence: 99%

Power-law singularity as a possible catastrophe warning observed in rock experiments

Hao

Feng

Ming-Fu

et al. 2013

International Journal of Rock Mechanics and Mining Sciences

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a b s t r a c tThe question which type of signals can be determinately related to catastrophic rupture in heterogeneous brittle media still remains open. Here we report a specific precursor of catastrophic rupture, i.e. a power-law singularity of responses, based on rock experiments. Our experimental observations show that the singularity with power exponent À b, where b¼0.5170.10 (mean 7 s.d.), appears ahead of catastrophic rupture in some rocks, and the singularity does not appear at all for gradual failure. It is indicated that the power-law singularity can emerge well only close to catastrophic rupture and thus it could serve as a specific warning for catastrophic rupture. To address the potential forewarning of imminent catastrophic rupture, a fitting process based on the data before catastrophic rupture was developed to determine the two unknowns related to the occurrence, catastrophe point U F and the power exponent À b u . It is demonstrated that the power-law singularity appears only in the vicinity of catastrophe, and that the power-law singularity does not occur for gradual failure.

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Section: Characteristics Of Responsesmentioning

confidence: 99%

Power-law singularity as a possible catastrophe warning observed in rock experiments

Hao

Feng

Ming-Fu

et al. 2013

International Journal of Rock Mechanics and Mining Sciences

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“…The practical implication of these observations is that, even with an infinitely stiff testing machine, it would still not be possible to trace the full stress-strain curves for rocks with Class II behaviour due to the elastic energy stored in the rock specimens themselves (Wawersik and Fairhurst, 1970).…”

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confidence: 99%

The influence of test specimen geometry on the laboratory-determined Class II characteristics of rocks

Vogler

Stacey

2016

J. South. Afr. Inst. Min. Metall.

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The behaviour of rocks depends on their material properties, and therefore it is important that these properties are determined by relevant and reliable laboratory testing methods. The ISRM Suggested Methods are very important documents in this regard, and a draft suggested method exists for the determination of the 'complete stress-strain curve for intact rock in uniaxial compression'. The method specifies the required geometry of specimens and the required testing procedures. The research described in this paper involved the determination of complete stress-strain curves for two materials, one exhibiting the Class I characteristic, and the other the Class II characteristic. To obtain a better understanding of the deformation behaviours in the post-peak region, tests were carried out on specimens of both material types with different length-to-diameter ratios. The results showed that the geometries of the test specimens influence the stressstrain curves in the post-peak region. The implication is, therefore, that the numerical values obtained for the slopes of the post-peak graphs are not material constants, but are geometry-dependent. Explanations for this behaviour are given. These findings have important implications regarding the use of post-peak data, for example for blast fragmentation considerations, and for evaluation of rockbursting potential. The research findings are based on a limited amount of laboratory testing, and should be confirmed by further testing. rock characteristics, Class I behaviour Class II behaviour, servo-controlled test, post-peak characteristics, specimen geometry, brittleness.

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“…Wawersik and Krajcinovic [26,27] proposed that damage is caused by microcracks and microvoid in the rock material. These microcrack and microvoid cannot bear any stress once formed.…”

Section: A Damage Constitutive Model Based On Acoustic Emissionmentioning

confidence: 99%

Determination of Damage Constitutive Behavior for Rock Salt Under Uniaxial Compression Condition with Acoustic Emission

Chen¹,

Zhang²,

Song³

et al. 2015

TOCIEJ

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Abstract:The mechanical characteristics of rock salt have an important influence on the safety of the salt cavity. The acoustic emission (AE) technique was used to analyze the generation of microcracks in rock salt under uniaxial compression condition. By monitoring acoustic emission in whole process of stress -strain curve under uniaxial compression test, the damage characteristic of rock salt is obtained. The AE rate-strain curve is able to reflect the damage development process with better consistency evident with the cracks generating. The failure form of rock salt is mainly the shear failure under condition of low loading strain rate. After shear failure, a lot of small crushed particles spread on the surface of the failure surface. A damage constitutive model of rock salt is determined on the basis of acoustic emission characteristics, which could reflect the strength and deformation characteristics before the peak strength.

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A study of brittle rock fracture in laboratory compression experiments

Cited by 703 publications

References 8 publications

Power-law singularity as a possible catastrophe warning observed in rock experiments

Power-law singularity as a possible catastrophe warning observed in rock experiments

The influence of test specimen geometry on the laboratory-determined Class II characteristics of rocks

Determination of Damage Constitutive Behavior for Rock Salt Under Uniaxial Compression Condition with Acoustic Emission

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