Size-dependent compressive strength properties of hard rocks and rock-like cementitious brittle materials

Darbor, Mohammad; Faramarzi, Lohrasb; Sharifzadeh, Mostafa

doi:10.1080/12269328.2018.1431961

Cited by 15 publications

(6 citation statements)

References 39 publications

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“…Besides, these strength data and Figure 3 show that a higher slenderness ratio leads to lower peak strength, which indicates that the slenderness ratio has a weak effect on sandstone. A similar phenomenon on peak strength was seen by other researchers [15,20,21,31]; they reported that the mechanical properties of a rock mass are controlled by both the behavior of preexisting discontinuities and the stress-fracture behavior of intact blocks making up the rock bridges between discontinuities. On the other hand, the nature of the shape effect is that real solid bodies always containing internal defects such as vacancies, dislocations, cracks, and inclusions of microvolumes of different strength randomly distributed within the volume.…”

Section: Effect Of Slenderness Ratio On the Mechanical Properties Ofsupporting

confidence: 81%

“…Unlike the hard rocks, saliferous rocks are notable for a directly contrary manifestation of the scale effect; that is, when the linear sizes of the sample increase, the ultimate compression strength also increases [17], and it is stabilized when the sample's size is greater than 10 cm [18]. In addition, other researchers also find that the specimen geometry on soft rock is generally not significant, and the correlation of uniaxial compression strength values in different diameters with estimations of specimen size effect models was weak [19]. To sum up, the specimen geometry is manifested differently depending on the rock type [20], and it needs further study considering different kinds of rocks.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Behavior and Energy Evolution of Sandstone considering Slenderness Ratio Effect

Dai

Xingdong

Zhang

et al. 2020

Advances in Civil Engineering

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To study the influence of slenderness ratio effect on the mechanical behavior, acoustic emission properties, and energy evolution of sandstone, the uniaxial compression tests coupled with acoustic emission technology are carried out at different slenderness ratios D (0.5, 1.0, 1.5, 2.0, 3.0). The results show that a logarithmic function relationship is observed between the peak strength, the peak strain, and the elastic modulus with slenderness ratio. The failure patterns of the tested sandstone varied significantly with the increasing slenderness ratio. When the slenderness ratio, D, is lower than 1.5, complex failures and multiple shear planes are formed, while simple failures and single shear planes are generated at D larger than 1.5. Besides, the AE ringing counts are more obvious with a higher slenderness ratio, D, at the initial compression stage due to the greater body volume and more defects in the sandstone. The energy evolution curves and energy ratio distribution curves can be divided into four stages, corresponding to the stress-strain curves.

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Section: Effect Of Slenderness Ratio On the Mechanical Properties Ofsupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Mechanical Behavior and Energy Evolution of Sandstone considering Slenderness Ratio Effect

Dai

Xingdong

Zhang

et al. 2020

Advances in Civil Engineering

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“…This result is also evident in Figure 8B. As a result, the weakening process of the sample is intensified, leading to increased brittleness (Darbor et al, 2019). From a failure perspective, stress concentration becomes more obvious at the end face of the sample as the L/D ratio decreases (Lundborg N, 1967), and the energy storage process is accelerated, leading to the ejection of rock fragments at a faster speed.…”

Section: Effect Of Strain Rate and L/d Ratio On Linear Energy Charact...mentioning

confidence: 68%

Experimental investigation into rock burst proneness of rock materials considering strain rate and size effect

Wang

Zhao

et al. 2023

Front. Earth Sci.

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In deep rock engineering, evaluating the likelihood of rock burst is imperative to ensure safety. This study proposes a new metric, the post-peak dissipated energy index, which accounts for strain rate and size effects in assessment of the rock burst proneness of a rock mass. To investigate rock burst proneness, conventional compression tests were conducted on limestone and slate samples with different length to diameter (L/D) ratios (ranging from 0.3 to 1.5) at four different strain rates (0.005, 0.01, 0.5, and 1.0 s−1). Based on the testing observations, the actual rock burst proneness was classified into three categories (no risk, low risk, and high risk). A new criterion was also established using the post-peak dissipated energy index, which is the ratio of elastic energy to total dissipated energy. The impact of the strain rate and L/D ratio on rock burst proneness was analyzed. The results indicated that increased strain rates cause a strong hardening effect, leading to staged growth of rock burst proneness. However, the rock burst proneness decreases non-linearly with the increasing L/D ratio. The accuracy of the proposed criterion was validated by comparison with existing criteria, demonstrating that the energy-based index ensures a reliable evaluation of the rock burst proneness of a rock mass. The proposed method has excellent potential for practical application in deep rock engineering.

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“…The results showed that the dynamic fracture toughness varied with the sizes of the specimens and the fracture process zone lengths, with the incubation times observed to increase with the increase in the sample size. Darbor et al 28 investigated the effects of specimen size on the strength levels of hard rock. The specimen size effect models were used thoroughly to analyze the laboratory data.…”

Section: Introductionmentioning

confidence: 99%

Crack Evolution Behaviors and Bursting Liability of Sandstone with Different Sizes: An Experimental Study

et al. 2023

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The size ranges of ore pillars play important roles in preventing the occurrences of rock burst phenomena. Due to the lack of research on the relationship between crack evolution behaviors and bursting liability of rocks with different sizes, uniaxial compression tests on sandstone with different height-todiameter ratios (H/D) were conducted. The results showed that the mechanical parameters of sandstone have obvious size effects, in which both the peak strength and peak strain decrease with increases in the H/D. Moreover, the brittle index modified value (BIM) decreased, but the impact energy index increased gradually, which indicated the increase of bursting liability. With the increases in the BIM, the overall crack strain parameters increased, thereby indicating a positive correlation. With the increase in the impact energy index, the crack strain decreased and the bursting liability became higher. Although the axial crack closure stress and axial crack damage stress increased with the increases in BIM (indicating a positive correlation), the bursting liability became increasingly smaller. The crack stress decreased with the increases in the impact energy index, and the bursting liability became stronger. The findings of this study will potentially provide experimental references for furthering the current understanding of the mechanism of rock bursts in underground coal mines in China.

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Size-dependent compressive strength properties of hard rocks and rock-like cementitious brittle materials

Cited by 15 publications

References 39 publications

Mechanical Behavior and Energy Evolution of Sandstone considering Slenderness Ratio Effect

Mechanical Behavior and Energy Evolution of Sandstone considering Slenderness Ratio Effect

Experimental investigation into rock burst proneness of rock materials considering strain rate and size effect

Crack Evolution Behaviors and Bursting Liability of Sandstone with Different Sizes: An Experimental Study

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