Responses of jointed rock masses subjected to impact loading

Aziznejad, Shabnam; Esmaieli, Kamran; Hadjigeorgiou, John; Labrie, D.

doi:10.1016/j.jrmge.2017.12.006

Cited by 51 publications

(18 citation statements)

References 23 publications

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“…These two effects result in joints with different undulations and different mechanical properties occur inside the rock mass. Joint is the key part of stress concentration and release, and its mechanical characteristics control the deformation and strength of rock mass (Aziznejad et al., 2018; Xie et al., 2020; Yang et al., 2019; Yong et al., 2018; Zhao et al., 2019), the instability and failure of slopes, tunnels and storage chambers often starts from the deterioration of the joint (Monsen and Barton, 2001; Rasouli Maleki, 2018; Shen et al., 2019, 2020; Zhao et al., 2020). The morphology and mechanical properties of joints are important factors affecting the stability evaluation of rock mass engineering.…”

Section: Introductionmentioning

confidence: 99%

Damage evolution characteristics of saw-tooth joint under shear creep condition

Zhang

Lin

Wang

et al. 2020

International Journal of Damage Mechanics

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The creep characteristics of joint have an important influence on the long-term stability of rock mass engineering such as tunnels and slopes. In this paper, the sawtooth angle α is taken as the variable, five different numerical models of regular sawtooth joints are established using the discrete element numerical method, to study the shear mechanical characteristics of joints under creep condition. In addition, the shear mechanical properties of joints under transient condition are compared to analysis the influence of creep on the mechanical characteristics of joint. The results show that under shear creep condition: (1) Shear displacement of joint increases stepwise with time. At low sawtooth angles, the difference of joint shear displacement with different normal stresses is large. The long-term shear strength of joint is proportional to normal stress and sawtooth angle. (2) The total absorbed energy U and elastic energy Ue of the joint both increase as the sawtooth angle α increases. Dissipated energy Ud tends to increase first and then decrease with increasing sawtooth angle. Compared with the energy characteristics under transient condition, it is found that the joint under creep condition not only has a lower shear strength, but also requires less total absorbed energy and dissipative energy, and fewer cracks at critical failure. (3) Before the peak strength, the damage variable D increases nonlinearly with the shear displacement. Compared with the transient condition, the damage amount corresponding to the peak strength under the creep condition is smaller, and the evolution rate of the damage variable D with shear displacement at the critical failure is higher.

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Section: Introductionmentioning

confidence: 99%

Damage evolution characteristics of saw-tooth joint under shear creep condition

Zhang

Lin

Wang

et al. 2020

International Journal of Damage Mechanics

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“…Rojek et al and Su & Akcin [24], [25] applied the discrete element method to simulate the rock cutting process, which shows that the numerical simulation can provide valuable information about the cutting phenomenon, and the numerical results are in good qualitative and quantitative agreement of numerical results with experimental measurements. Aziznejad et al [26] simulated the response of jointed rock mass subjected to impact loading. They found that joints play an important role in the impact-induced rock mass damage where higher joint intensity results in more damage to the rock mass.…”

Section: Introductionmentioning

confidence: 99%

Finite Element Method for Prediction of Rock Breaking Performance of the Tipped Hob With Different Tooth Profiles

Jiang

2020

IEEE Access

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The raise boring machine, which plays a crucial role in wellbore construction, has been widely applied in subway tunnels and mine construction projects. High levels of quality and safety, make it recognized and promoted by an increasing number of users. The tipped hob as a rock-breaking cutter of the raise boring machine poses a direct influence on the efficiency of the well-bore construction. In this paper, the finite element software LS-DYNA is employed to establish the model of the crushed rock with the tipped hob, and the accuracy of the model is examined by experiments. On this basis, the variation laws and correlations of feed force, lateral force and positive force under different penetration depths are studied. The results show that as the penetration depth increases, the feed force, lateral force and positive force all grow exponentially. In the geological environment with high rock hardness, spherical tooth can effectively reduce cutter wear and conical tooth can achieve higher crushing ability. The research results provide a theoretical basis for the selection of a suitable tipped hob to improve rock breaking efficiency. INDEX TERMS Raise boring machine, rock breaking, tooth profile, tipped hob, numerical simulation.

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“…erefore, rock mass instability caused by natural or human activities is studied, such as earthquakes, excavations, and mining vibrations, and this not only destroys the stress balance of original rock but also leads to the phenomenon of stress redistribution [1], thus causing the changes of the physical and mechanical properties. Take the loading and unloading processes of rock stress as an example, and there will be pores evolution such as the closure of primary pores and the initiation and expansion of new pores, resulting in different damage degrees of the rock mass [4][5][6][7]. However, the rock mass instability induced by those natural and human activities is closely related to stress wave propagation.…”

Section: Introductionmentioning

confidence: 99%

“…Currently, given the blasting excavation of deep engineering rock mass, the research focus can be divided into dynamic response problems [4,6,8,9] and stress wave propagation problems [10][11][12]. However, since the complexity and discontinuity of the rock mass, the propagation and attenuation characteristics of stress waves are also very complicated, so there is no unified quantitative relationship to describe those attenuation mechanisms [4].…”

Section: Introductionmentioning

confidence: 99%

“…Engineering practice has shown that the change in original rock stress is calculated in milliseconds [13]; this indicates the necessity to study the dynamic response problem during the rock mass excavation. us, to meet the engineering needs, the impact damage, deformation and failure characteristics, and energy dissipation mechanism of the rock mass have been studied theoretically and practically, and the relevant theories and numerical models have been established [6,14,15].…”

Section: Introductionmentioning

confidence: 99%

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Attenuation Characteristics of Stress Wave Peak in Sandstone Subjected to Different Axial Stresses

Cheng

Song

Jin

et al. 2019

Advances in Materials Science and Engineering

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To investigate the effect of axial stress on the attenuation characteristics of stress wave peaks, stress wave propagation experiments with small disturbance of a sandstone bar were carried out by a modified split Hopkinson pressure bar test system. Then, effects of axial stress on the waveform, attenuation rate, temporal-spatial attenuation characteristics, and attenuation sensitivity factor of the peak were studied. The results showed that the presence or absence of axial stress has a significant effect on the waveform. With axial stress loading, both temporal and spatial attenuation rates undergo similar development stages, “nonlinear stage + linear stage,” in which the demarcation stress (σ/σc) is 30%. Under the same axial stress, the peak decreases exponentially with the propagation time and distance with different attenuation intensities. With increasing axial stress, the temporal and spatial response intensities also experience “nonlinear stage + linear stage.” However, the temporal and spatial attenuation coefficients undergo three stages, first a dramatic decrease, then gentle development, and finally a sharp increase, in which demarcation stresses (σ/σc) are 30% and 55%. The defined attenuation sensitivity factor can well describe the attenuation sensitivity of peaks to different axial stresses. The conclusions can provide a theoretical reference for rock mass stability analysis in blasting excavation.

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Responses of jointed rock masses subjected to impact loading

Cited by 51 publications

References 23 publications

Damage evolution characteristics of saw-tooth joint under shear creep condition

Damage evolution characteristics of saw-tooth joint under shear creep condition

Finite Element Method for Prediction of Rock Breaking Performance of the Tipped Hob With Different Tooth Profiles

Attenuation Characteristics of Stress Wave Peak in Sandstone Subjected to Different Axial Stresses

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