Suggested methods for determining the dynamic strength parameters and mode-I fracture toughness of rock materials

Zhou, Yingxin; Xia, Kaiwen; Li, X.B.; Li, H.B.; Ma, Guowei; Zhao, Jun; Zhou, Zilong; Dai, Feng

doi:10.1016/j.ijrmms.2011.10.004

Cited by 703 publications

(227 citation statements)

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“…Special care was taken to prepare the Brazilian disc specimens with a thickness of 16 mm. All specimens were polished to have a surface roughness of less than 0.5 % of the sample thickness, following the ISRM suggested method (Zhou et al 2012). …”

Section: Specimen Preparationmentioning

confidence: 99%

“…The experimental apparatus is the modified split Hopkinson pressure bar (SHPB) system, which includes three bars (a striker bar, an incident bar, and a transmitted bar) (Zhou et al 2012) and a hydraulic system (Fig. 2).…”

Section: Experimental Apparatusmentioning

confidence: 99%

“…The strains of incident wave, reflected wave, and transmitted wave are denoted by e i , e r , and e t , respectively. Based on the one-dimensional stress wave theory, and assuming stress equilibrium during loading (Zhou et al 2012) (i.e., e i þ e r ¼ e t ), the history of the force on the two ends of the sample is:…”

Section: Data Reductionmentioning

confidence: 99%

“…Existing studies (Dai et al 2010b;Zhou et al 2012) have demonstrated that BD tests are valid when the stress equilibrium condition is satisfied. In this paper, five groups of samples are tested under the hydrostatic confinements of 0, 5, 10, 15, and 20 MPa.…”

Section: Effects Of Loading Rate and Hydrostatic Confinementmentioning

confidence: 99%

“…For example, CT imaging has been used to characterize the internal structure of geomaterials such as soil (Elyeznasni et al 2012;Garbout et al 2013;Hapca et al 2015;Otani et al 2001), rock (Huang et al 2013;Huang and Xia 2015;Ito et al 2001;Liu et al 2014b;Sugawara et al 2004;Vervoort et al 2004), concrete (Darma et al 2013;Fukuda et al 2014;Henry et al 2014), and asphalt (Liu et al 2014a;Masad and Kassem 2009;Taniguchi et al 2012;Tomoto and Moriyoshi 2009). In this paper, the Brazilian disc (BD) sample is adopted to measure the dynamic tensile strength of rock materials (Zhou et al 2012) under hydrostatic confinement. A modified split Hopkinson pressure bar (SHPB) system is developed to provide and maintain the hydrostatic confinement on the rock sample before the dynamic load is applied.…”

Section: Introductionmentioning

confidence: 99%

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An Experimental Study of Dynamic Tensile Failure of Rocks Subjected to Hydrostatic Confinement

Yao

Xia

2016

Rock Mech Rock Eng

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It is critical to understand the dynamic tensile failure of confined rocks in many rock engineering applications, such as underground blasting in mining projects. To simulate the in situ stress state of underground rocks, a modified split Hopkinson pressure bar system is utilized to load Brazilian disc (BD) samples hydrostatically, and then exert dynamic load to the sample by impacting the striker on the incident bar. The pulse shaper technique is used to generate a slowly rising stress wave to facilitate the dynamic force balance in the tests. Five groups of Laurentian granite BD samples (with static BD tensile strength of 12.8 MPa) under the hydrostatic confinement of 0, 5, 10, 15, and 20 MPa were tested with different loading rates. The result shows that the dynamic tensile strength increases with the hydrostatic confining pressure. It is also observed that under the same hydrostatic pressure, the dynamic tensile strength increases with the loading rate, revealing the so-called rate dependency for engineering materials. Furthermore, the increment of the tensile strength decreases with the hydrostatic confinement, which resembles the static tensile behavior of rock under confining pressure, as reported in the literature. The recovered samples are examined using X-ray micro-computed tomography method and the observed crack pattern is consistent with the experimental result. Keywords Dynamic tensile strength Á Hydrostatic confinement Á Brazilian disc Á SHPB Á Rate dependence Á X-ray CT Abbreviations SHPB Split Hopkinson pressure bar BD Brazilian disc CT Computed tomography LG Laurentian granite ISRM International Society for Rock Mechanics List of SymbolsA b Cross-sectional area of the bars (mm 2 ) A s Contact area between the sample and the transmitted bar (mm 2 ) r 0 Pump oil pressure (MPa) r 1 Stresses of the sample at the transmitted bar end (MPa) r 2 Stresses of the sample at the incident bar end (MPa) e i Incident strain wave e r Reflected strain wave e t Transmitted strain wave P 1 Force on incident end of the Brazilian disc specimen (N) P 2 Force on transmitted end of the Brazilian disc specimen (N) E b Young's modulus of the bars (GPa) B Thickness of the Brazilian disc specimen (mm) D Diameter of the Brazilian disc specimen (mm) r Tensile stress at the center of the Brazilian disc specimen (MPa) S Dynamic tensile strength of the Brazilian disc specimen (MPa) S 0 Static Brazilian tensile strength of Laurentian granite (MPa) & Kaiwen Xia

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Section: Specimen Preparationmentioning

confidence: 99%

Section: Experimental Apparatusmentioning

confidence: 99%

Section: Data Reductionmentioning

confidence: 99%

Section: Effects Of Loading Rate and Hydrostatic Confinementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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An Experimental Study of Dynamic Tensile Failure of Rocks Subjected to Hydrostatic Confinement

Yao

Xia

2016

Rock Mech Rock Eng

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Numerical modeling of dynamic rock fracture with a combined 3D continuum viscodamage‐embedded discontinuity model

Saksala

Brancherie

Ibrahimbegović

2016

Num Anal Meth Geomechanics

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Summary This paper deals with numerical modeling of dynamic failure phenomena in rate‐sensitive quasi‐brittle materials, such as rocks, with initial microcrack populations. To this end, a continuum viscodamage‐embedded discontinuity model is developed and tested in full 3D setting. The model describes the pre‐peak nonlinear and rate‐sensitive hardening response of the material behavior, representing the fracture‐process zone creation, by a rate‐dependent continuum damage model. The post‐peak response, involving the macrocrack creation accompanied by exponential softening, is formulated by using an embedded displacement discontinuity model. The finite element implementation of this model relies upon the linear tetrahedral element, which seems appropriate for explicit dynamic analyses involving stress wave propagation. The problems of crack locking and spreading typical of embedded discontinuity models are addressed in this paper. A combination of two remedies, the inclusion of viscosity in the spirit of Wang's viscoplastic consistency approach and introduction of isotropic damaging into the embedded discontinuity model, is shown to be effective in the present explicit dynamics setting. The model performance is illustrated by several numerical simulations. In particular, the dynamic Brazilian disc test and the Kalthoff–Winkler experiment show that the present model provides realistic predictions with the correct failure modes and rate‐dependent tensile strengths of rock at different loading rates. The ability of initial embedded discontinuity populations to model the initial microcrack populations in rocks is also successfully tested. Copyright © 2016 John Wiley & Sons, Ltd.

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Study on mechanical properties of (1 % PVA fiber +1 % Steel fiber) PS‐ECC under the coupling effects of elevated temperature and dynamic loads

Chen

Zhu

Zhou

et al. 2023

Structural Concrete

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The coupling effect of temperature and impact loads can cause the concrete strength to decay and lead to the failure of the structure that cannot reach the designed load‐bearing strength. In this study, the evolution laws of dynamic compressive strength, dynamic increase factor (DIF), and absorbed energy of (1% polyvinyl alcohol [PVA] fiber +1% steel fiber) PS‐ECC (engineered cementitious composite) were obtained by a split Hopkinson compression bar test. The conclusions can be concluded: the dynamic compressive strength, DIF, and absorbed energy of PS‐ECC largely show a tendency to decrease with increasing temperature; however, the recovery effect occurs at 200°C due to the accumulation of steam inside the specimen to counteract the impact force. Then, 200°C becomes a threshold value, and the sensitivity of PS‐ECC to strain rate shows a steep drop when the temperature exceeds 200°C. Compared to 200°C, the growth rate of dynamic compressive strength, DIF, and energy absorption capacity from strain rate 50–80 s−1 decreases by 50.65, 55.24, and 45.71% at 300°C, the growth rate decreases by 55.87, 56.5, and 48.45% at 400°C. The impact energy absorption of PS‐ECC was provided mainly by PVA fiber. The energy absorption of PS‐ECC is almost the same at 300 and 400°C for the same strain rate due to PVA fiber burning disappears.

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Suggested methods for determining the dynamic strength parameters and mode-I fracture toughness of rock materials

Cited by 703 publications

References 8 publications

An Experimental Study of Dynamic Tensile Failure of Rocks Subjected to Hydrostatic Confinement

An Experimental Study of Dynamic Tensile Failure of Rocks Subjected to Hydrostatic Confinement

Numerical modeling of dynamic rock fracture with a combined 3D continuum viscodamage‐embedded discontinuity model

Study on mechanical properties of (1 % PVA fiber +1 % Steel fiber) PS‐ECC under the coupling effects of elevated temperature and dynamic loads

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