Brazilian Tests on Transversely Isotropic Rocks: Laboratory Testing and Numerical Simulations

Tan, Xiaolu; Konietzky, Heinz; Frühwirt, Thomas; Dan, Dinh Quoc

doi:10.1007/s00603-014-0629-2

Cited by 162 publications

(56 citation statements)

References 14 publications

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“…A number of researchers have carried out studies on the effect of anisotropic properties on the Brazilian tensile strength (Khanlari et al 2014a(Khanlari et al & 2014bTan et al 2014). Based on the assessment of the influence of strength anisotropy on the measured peak strength for four different types of rock samples in the Brazilian test, Dan et al (2013) deemed that: 1) the degree of anisotropy has a strong influence on the measured peak strength; 2) the orientation of the sample in relation to the loading direction is not important for nearly-isotropic materials; and 3) strongly anisotropic materials show a strong dependence of the peak strength on the sample orientation relative to the loading direction.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study On The Effect Of Micro-Cracks On Brazilian Tensile Strength

Wang¹

2015

Archives of Mining Sciences

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For coal mine ground control issues, it is necessary to propose a failure criteria accounting for the transversely isotropic behaviors of rocks. Hence, it is very helpful to provide experimental data for the validation of the failure criteria. In this paper, the method for preparing transversely isotropic specimens and the scheme of the Brazilian tensile strength test are presented. Results obtained from Brazilian split tests under dry and water-saturated conditions reflect the effect of the development direction β of the structural plane, such as the bedding fissure, on the tensile strength, ultimate displacement, failure mode, and the whole splitting process. The results show that the tensile strength decreases linearly with increasing β. The softening coefficient of the tensile strength shows a sinusoidal function. The values of the slope and inflection point for the curve vary at the different stages of the Brazilian test. The failure mode of the rock specimen presented in this paper generally coincides with the standard Brazilian splitting failure mode. Based on the test results, the major influencing factors for the Brazilian splitting strength are analyzed and a mathematical model for solving the Brazilian splitting strength is proposed. The findings in this paper would greatly benefit the coal mine ground control studies when the surrounding rocks of interest show severe transversely isotropic behaviors.Keywords: Brazilian split test; Dry and water saturation; Bedding fissure; Strength coefficient; Coal mine ground control W związku z zagadnieniami ochrony powierzchni w kopalniach węgla, konieczne jest opracowanie odpowiednich kryteriów klasyfikacji uszkodzeń skał uwzględniających ich poprzeczną izotropowość. Pomocnym jest także dostarczenie danych eksperymentalnych niezbędnych do walidacji kryteriów uszkodzeń. W pracy tej zaproponowano metodę przygotowywania próbek wykazujących izotropowość poprzeczną, omówiono także sposób przeprowadzania testu na rozciąganie metodą brazylijską. Wyniki testu uzyskane na sucho oraz w warunkach nasycenia próbki wodą wskazują wpływ kierunku rozwoju β płaszczyzny strukturalnej (np. płaszczyzn spękań) na wytrzymałość próbki na rozciąganie, maksymalne przemieszczenia, rodzaj uszkodzenia oraz przebieg procesu pękania. Wyniki testu wskazują, że wytrzymałość na rozciąganie maleje liniowo wraz ze wzrostem wartości β. Współczynnik mięknienia próbki w trakcie próby wytrzymałościowej na rozciąganie ma przebieg krzywej sinusoidalnej. Wartości kąta nachylenia oraz punkt przegięcia krzywej różnią się dla poszczególnych etapów próby wytrzymałościowej. Tryb uszkodzeń próbek skalnych przedstawiony w artykule zasadniczo pozostaje w zgodzie z typowymi odkształceniami rejestrowanymi w trakcie testu metodą brazylijską. W oparciu o wyniki eksperymentu, przeanalizowano główne czynniki wpływające na wytrzymałość próbek na rozciąganie i zaproponowano odpowiedni model matematyczny do obliczania wytrzymałości. Wyniki przedstawione w artykule stanowią poważny przyczynek do badań stabilności gruntu...

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Section: Introductionmentioning

confidence: 99%

Experimental Study On The Effect Of Micro-Cracks On Brazilian Tensile Strength

Wang¹

2015

Archives of Mining Sciences

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“…UDEC is a two-dimensional numerical program based on the distinct element method for discontinuity modelling. It has been widely used in the literature to explore damage of rock [24][25][26][27][28][29], as well as Brazilian test analysis [30,31]. UDEC especially joint model used in UDEC captures several features that are representative of the physical response of joints.…”

Section: Introduction About Distinct Elementmentioning

confidence: 99%

A Numerical Research on Crack Process of Gypsum Containing Single Flaw with Different Angle and Length in Uniaxial Loading

Dai

Zhang

2018

Shock and Vibration

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To investigate the crack behaviour of rock or rock-like material in uniaxial loading, a series of numerical simulations were conducted on gypsum specimens containing a single flaw with different inclination angle (0 ∘ -90 ∘ ) and length (10 mm-30 mm). Based on the numerical simulations results, the effect of flaw length on peak strength, the CI stress, and the CD stress were investigated with different inclination angles. The results show that the peak strength decreased initially and then increased with increasing of the flaw angle. Meanwhile, the peak strength decreased gradually when the length of the preexisting flaw increased. When the inclination angle was 30 ∘ , 45 ∘ , and 60 ∘ , the reduction degree of peak strength increased with increasing of the flaw length. The CI stress and CD stress not only depend on the inclination angle but also depend on flaw length. Four types of crack were observed in numerical simulations. The present research facilitates increased understanding of crack behaviour of rock under different conditions.

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“…For numerical simulation, Dan and Konietzky [12] have found that the failure patterns of transverse isotropic rocks can be classified into three types (pure tensile failure, matrix-bedding tensile-shear failure, and bedding tensileshear failure) with foliation-loading angle varying. By using the discrete element method, Tan et al [13] have drew a diagram which reflects the relationship between tensile strength, failure patterns, and foliation-loading angle of transverse isotropic rocks.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Fracturing Behavior of Layered Rock with Different Inclination Angles in SHPB Tests

Qiu

et al. 2017

Shock and Vibration

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The fracturing behavior of layered rocks is usually influenced by bedding planes. In this paper, five groups of bedded sandstones with different bedding inclination angles are used to carry out impact compression tests by split Hopkinson pressure bar. A highspeed camera is used to capture the fracturing process of specimens. Based on testing results, three failure patterns are identified and classified, including (A) splitting along bedding planes; (B) sliding failure along bedding planes; (C) fracturing across bedding planes. The failure pattern (C) can be further classified into three subcategories: (C1) fracturing oblique to loading direction; (C2) fracturing parallel to loading direction; (C3) mixed fracturing across bedding planes. Meanwhile, a numerical model of layered rock and SHPB system are established by particle flow code (PFC). The numerical results show that the shear stress is the main reason for inducing the damage along bedding plane at = 0 ∘ ∼75∘ . Both tensile stress and shear stress on bedding planes contribute to the splitting failure along bedding planes when the inclination angle is 90 ∘ . Besides, tensile stress is the main reason that leads to the damage in rock matrixes at = 0 ∘ ∼90∘ .

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Brazilian Tests on Transversely Isotropic Rocks: Laboratory Testing and Numerical Simulations

Cited by 162 publications

References 14 publications

Experimental Study On The Effect Of Micro-Cracks On Brazilian Tensile Strength

Experimental Study On The Effect Of Micro-Cracks On Brazilian Tensile Strength

A Numerical Research on Crack Process of Gypsum Containing Single Flaw with Different Angle and Length in Uniaxial Loading

Dynamic Fracturing Behavior of Layered Rock with Different Inclination Angles in SHPB Tests

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