SHPB test analysis and a constitutive model for frozen soil under multiaxial loading

Zhu, Zhiwu; Cao, Chenxu; Fu, Tiantian

doi:10.1177/1056789519867471

Cited by 17 publications

(13 citation statements)

References 35 publications

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“…(2017) proposed a nonlinear viscoelastic constitutive model to reflect the confining pressure effect of frozen soil under impact loading. Zhu et al. (2020) proposed a dynamic constitutive model for frozen soil under passive confining pressure, considering the damage to ice particles and soil matrix.…”

Section: Introductionmentioning

confidence: 99%

“…Based on the Zhu-Wang-Tang model, Ma et al (2017) proposed a nonlinear viscoelastic constitutive model to reflect the confining pressure effect of frozen soil under impact loading. Zhu et al (2020) proposed a dynamic constitutive model for frozen soil under passive confining pressure, considering the damage to ice particles and soil matrix. To describe the effect of freezing-thawing on the impact behaviors of frozen soil, Li et al (2022) established a viscoelastic-plastic constitutive model of frozen soil under cyclic freeze-thaw and impact loading by introducing the Drucker-Prager yield criterion into the Zhu-Wang-Tang model.…”

Section: Introductionmentioning

confidence: 99%

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Numerical simulation research on impact mechanical properties of frozen soil based on discrete element method

Chunyu

Zhu

et al. 2022

International Journal of Damage Mechanics

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Many engineering activities have been conducted on permafrost. Frozen soil is subjected to impact loading, particularly during blasting and excavation projects. Thus, it is essential to study the impact mechanical properties of frozen soil. A split Hopkinson pressure bar (SHPB) experiment was conducted to investigate the mechanical responses of frozen soil specimens subjected to impact loading under different strain rates at different temperatures. Evident strain rate and temperature effects were also observed. As crack development in the specimens could not be observed experimentally, a two-dimensional particle flow code was utilized to numerically simulate SHPB impact experiments on frozen soil. A contact bonding model was used for the simulation. We assumed that only temperature could change the particle parameters. The parameters and establishment of the geometric model in the simulation were calibrated and validated by comparing them with the experimentally obtained impact stress–strain curves and wave signals. More influences of strain rate and temperature on crack development were presented intuitively in this study, in combination with the propagation of stress waves. The results of the numerical simulation demonstrated that when the frozen soil specimen was subjected to impact loading, shear failure was the primary failure in the specimen. For a given temperature, a lower strain rate decreased the number of cracks generated, increased the duration of crack generation, and delayed the formation of cracks. For a given strain rate, a lower temperature decreased the number of cracks generated and the duration of crack generation; however, the number of tensile cracks was negligibly affected by changes in temperature.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical simulation research on impact mechanical properties of frozen soil based on discrete element method

Chunyu

Zhu

et al. 2022

International Journal of Damage Mechanics

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“…Coal rock is a kind of porous material. The volume of moisture in coal pores and fractures expands by 9% when it freezes into ice, and 270 MPa frost heaving force is produced at the tip of pores and fractures (Bai et al., 2021; Gao et al., 2018; Li et al., 2016; Zhu et al., 2020). Besides, LN 2 gasification may produce high pressure, and coal fractures may participate in coal breakage.…”

Section: Introductionmentioning

confidence: 99%

Effects of cyclic freeze-thaw by liquid nitrogen on the coal breakage properties and fragment size distribution

Chong

Yao

et al. 2022

International Journal of Damage Mechanics

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Transforming intact coal seams into broken coals that are convenient to transport is one of the technical problems of fluidized coal mining. In this paper, cyclic freeze-thaw by liquid nitrogen (CFT-LN2) was adopted to improve the fragmentation degree of coal seams. The coal pore structure evolutions and coal breakage properties were explored using the acoustic emission (AE) parameter method (the kernel density estimation method), the fractal theory, and the nuclear magnetic resonance spectra. The main factors discussed include the number of freeze-thaw cycles, the LN2 freezing time and the moisture content of the coal sample. Variations of these factors alter the mechanical and physical characteristics and pore structures of coal samples treated with CFT-LN2. The results reveal that the kernel density estimation method can distinguish the density region determined based on the rise angle (RA) and average frequency (AF) values and visualize the rupture modes of coal samples formed after CFT-LN2. As the number of freeze-thaw cycles grows, the tensile rupture mode gradually transits to shear rupture mode; the fractal dimension gradually increases; the equivalent average size gradually decreases; and the mass of different fragment sizes tend to be more uniform. Only freezing in LN2 without CFT-LN2 cannot notably change the rupture mode or fragmentation degree of a coal sample. During CFT-LN2, the coal matrix is subjected to repeated action of contraction in LN2 and expansion at room temperature. As a result, new micro-pores are formed easily in the matrix, and micro-pores incline to connect into larger pores. Meanwhile, increasing the moisture content is conducive to coal fracturing through CFT-LN2.

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“…Zhai et al [11] proposed a dynamic model of viscoelastoplastic damage, and its applicability was verified by the SHPB experiment of two rock materials. Based on the dynamic mechanical behavior results of frozen soil at different temperatures and high strain rates, a dynamic constitutive model of frozen soil under a multiaxial state was proposed by Zhu et al [12]. e dynamic constitutive model of secondary loading surface of rock materials constructed by Zhou et al [13] could reflect the hysteretic loop characteristics and rate effect under seismic loads.…”

Section: Introductionmentioning

confidence: 99%

Experiment and Applications of Dynamic Constitutive Model of Tensile and Compression Damage of Sandstones

Dong

Zhao

et al. 2021

Advances in Materials Science and Engineering

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A dynamic constitutive model of tensile and compressive damage was constructed on the basis of the ZWT and statistical damage models, particularly by introducing the maximum tension and maximum shear stress criteria to solve the failure problem of the surrounding rock mass caused by deep excavation unloading. A shock compression and splitting test of sandstone specimens under different strain rates were performed by using a split Hopkinson pressure bar (SHPB). The constitutive model was developed again by LS-DYNA for the secondary numerical impact compression and split test of sandstones. Results demonstrated that the constructed dynamic constitutive model of tensile and compressive damage could considerably simulate tensile and compressive stress-strain relations and failure features of sandstones well. Lastly, the constitutive model was applied to conduct a numerical study on damage distribution and failure laws of the surrounding rocks at Gaochou Roadway, Luling Mine under cyclic excavation unloading. Results showed that the unloading failure of surrounding rocks has significant accumulation effects, and the accumulated damage on the floor is larger than those on the roof and roadway walls. The maximum breaking and damage depths are 0.4 m and 5.31 m, respectively. Circumferential damage showed an “umbrella-shaped” distribution pattern. With respect to trend, the damage accumulation effect at the rear part of the excavation face is stronger than that at the front part and the maximum influence distance is 6.4 m. However, the influencing degree of the accumulation effect attenuates gradually as advancing into the excavation face. The reliability of the numerical simulation is verified by combining the test results of the field geological radar on the roadway roof.

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SHPB test analysis and a constitutive model for frozen soil under multiaxial loading

Cited by 17 publications

References 35 publications

Numerical simulation research on impact mechanical properties of frozen soil based on discrete element method

Numerical simulation research on impact mechanical properties of frozen soil based on discrete element method

Effects of cyclic freeze-thaw by liquid nitrogen on the coal breakage properties and fragment size distribution

Experiment and Applications of Dynamic Constitutive Model of Tensile and Compression Damage of Sandstones

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