Fracture prediction of rocks under mode I and mode II loading using the generalized maximum tangential strain criterion

Wei, Mingdong; Dai, Feng; Xu, Nuwen; Liu, Yi; Zhao, Tao

doi:10.1016/j.engfracmech.2017.09.026

Cited by 115 publications

(38 citation statements)

References 82 publications

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“…The most important material parameter in rock fracture mechanics is fracture toughness, which represents the resistance of rocks against fracturing. For brittle rocks, the opening mode (ie, mode I) fracture is more likely to occur than the sliding mode (ie, mode II) and the tearing mode (ie, mode III); thus, determination of mode I fracture toughness ( K Ic ) of rock has attracted widespread interests . Many valuable test methods using different specimen geometries and loading types have been proposed to measure K Ic ; some of them are reviewed in Table .…”

Section: Introductionmentioning

confidence: 99%

An experimental and theoretical comparison of CCNBD and CCNSCB specimens for determining mode I fracture toughness of rocks

Wei

Dai

Liu

et al. 2017

Fatigue Fract Eng Mat Struct

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The cracked chevron notched Brazilian disc (CCNBD) specimen, suggested by the International Society for Rock Mechanics for testing mode I fracture toughness of rocks, usually yields rather conservative toughness measurements, and the reasons have not been fully explored. In this study, the CCNBD method is compared with the cracked chevron notched semicircular bending (CCNSCB) method in the fracture process zone (FPZ) and its influence on the fracture toughness measurement. Theoretical analysis reveals that the FPZ is longer in the CCNBD specimen than in the CCNSCB specimen using a relatively large support span, the toughness measurement using the former is affected more seriously by the presence of FPZ, and thus the CCNBD method is usually, more or less, conservative compared with the CCNSCB method. These inferences are further validated by experimental results, which indicate that the CCNBD test indeed produces much lower fracture toughness values and even the results of 75‐mm radius CCNBD specimens are still lower than those of 25‐mm radius CCNSCB specimens. Consequently, due to smaller FPZ, the CCNSCB specimen with a relatively large span is more likely to produce comparably accurate or representative toughness value, and it may be more suitable than the CCNBD specimen for the engineering applications that require more representative or less conservative fracture toughness.

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Section: Introductionmentioning

confidence: 99%

An experimental and theoretical comparison of CCNBD and CCNSCB specimens for determining mode I fracture toughness of rocks

Wei

Dai

Liu

et al. 2017

Fatigue Fract Eng Mat Struct

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“…The fracture toughness of brittle materials is reduced due the existence of pre-existing cracks (Kato & Nishioka, 2005). Intensive theoretical and experimental studies have frequently devoted their effort to brittle failure in engineering structures and components with cracks and/or notches Aliha et al, 2014Aliha et al, , 2016Ayatollahi et al, 2015;Fakhri et al, 2017;Fayed, 2008Fayed, , 2017Fayed et al, 2008;Hammouda et al, 2003aHammouda et al, , 2004Hammouda et al, , 2002Razmi & Mirsayar, 2017;Wei et al, 2016Wei et al, , 2017a. It was experimentally noticed that crack extension occurred in mode I rather than shear mode or mixed mode.…”

Section: Introductionmentioning

confidence: 99%

Numerical evaluation of mode I/II SIF of quasi-brittle materials using cracked semi-circular bend specimen

Fayed¹

2018

10.5267/j.esm

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An in-house finite element code was utilized to evaluate mode I/II stress intensity factor (SIF) of an edge cracked semi-circular disc subjected to three-point bending. The specimen was considered as an isotropic and homogeneous material. Relative span length ratios of 0.3 to 0.8 in steps of 0.1 were invoked. Relative crack length ratios of 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 were analyzed with crack angles up to 60° in steps of 5°. At the same crack length, mode I SIF decreases with increasing crack angle or decreasing the span length. The range of pure mode II decreases with increasing the span length. For the same crack length, the crack angle corresponding to the transition from a mixed mode I/II to a pure mode II increases with increasing the relative span length ratio. On the contrary, that angle decreases with increasing the crack length for the same span length. Good agreement has been generally obtained with relevant results found in the literature.

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“…Currently, a large number of underground structures (eg, coal mine roadways, underground tunnels, and chemical and nuclear waste repositories) are constructed in this type of rock . In the design and stability analysis of this type of underground structure, it is necessary to consider the anisotropic deformation and failure characteristics of the layered rocks. Thus, mechanical models need to be established that can sufficiently reflect the anisotropic characteristics of layered rocks and thoroughly explain their transversely isotropic deformation and failure characteristics .…”

Section: Introductionmentioning

confidence: 99%

Anisotropic modeling of layered rocks incorporating planes of weakness and volumetric stress

Tan

Zhou

et al. 2019

Energy Science & Engineering

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Layered rocks exhibit notable transverse isotropy and have a significant impact on the deformation and failure characteristics of underground structures. To a large extent, the mechanical properties of layered rocks are related to the structure and stress state of their bedding planes. To obtain an in‐depth understanding of the deformation and yield characteristics of layered rocks, a mechanical model for layered rocks incorporating planes of weakness and volumetric stress is proposed by improving the strain‐hardening/softening ubiquitous‐joint model based on continuum mechanics methods. In this mechanical model, elastoplastic equations for the matrix and bedding planes of layered rocks are established. The evolution of the mechanical parameters of the matrix and bedding planes of layered rocks with the internal variable is determined. In addition, the sensitivity of the model parameters is analyzed, and a method for determining the parameters is provided to reduce the complexity in obtaining these parameters. The numerical calculation results for the laboratory tests on layered sandstone specimens under various stress levels agree relatively well with the test results, thereby validating the effectiveness of the improved model. The methods and results of this study provide a significant reference for the analysis of the deformation and failure of other layered rocks.

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Fracture prediction of rocks under mode I and mode II loading using the generalized maximum tangential strain criterion

Cited by 115 publications

References 82 publications

An experimental and theoretical comparison of CCNBD and CCNSCB specimens for determining mode I fracture toughness of rocks

An experimental and theoretical comparison of CCNBD and CCNSCB specimens for determining mode I fracture toughness of rocks

Numerical evaluation of mode I/II SIF of quasi-brittle materials using cracked semi-circular bend specimen

Anisotropic modeling of layered rocks incorporating planes of weakness and volumetric stress

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