Experimental study on rock-like materials fragmentation by electric explosion method under high stress condition

Peng, Jun; Zhang, Fengpeng; Yan, Guangliang; Qiu, Zhaoguo; Dai, Xinghang

doi:10.1016/j.powtec.2019.09.001

Cited by 26 publications

(6 citation statements)

References 28 publications

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“…The axial stress at failure (σ 1 ) under different confining pressures (σ 2 = σ 3 ) can be calculated by Equation (4). The results are shown in Table 1.…”

Section: Failure Surface Parametersmentioning

confidence: 99%

“…The results showed that the cracks induced by blasting stress wave and gas pressure grow preferably in the direction of maximum principal stress of superimposed stress fields. Zhang and Peng [2][3][4][5] studied the crater blasting under different confining pressures via theoretical analysis and physical model tests. The outcomes showed that the crater shape becomes oval with the long axis aligned on the loading direction, and the open angle in this direction and the crater volume is greater with the increase of confining pressure under uniaxial static load.…”

Section: Introductionmentioning

confidence: 99%

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Study on Rock Damage Mechanism for Lateral Blasting under High In Situ Stresses

et al. 2021

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A 3D numerical model was presented to investigate the blast-induced damage characteristics of highly stressed rock mass. The RHT (Riedel, Hiermaier, and Thoma) model in LS-DYNA was used to simulate the blast-induced damage and its parameters were calibrated by a physical model test. Based on the calibrated numerical model, the influences of confining pressure and free surface span on the blast-induced damage characteristics were investigated. The results show that under uniaxial loading, the crater volume increases with confining pressure increases. The uniaxial static load can change the optimal burden and the critical embedding depth of charge. In stressed rock, the variation law of the crater shape affected by radial tensile fractures is opposite to that affected by reflected tensile fractures. Under the biaxial static load, the crater volume of the borehole placed on the side of the max static load is greater than the other side. The explosion crater can be improved by increasing the free surface span on the same side. Finally, it is suggested that the blasting efficiency can be improved by preferentially detonating the charge on the side of the max static load, and then the charge on the other side can be detonated with a wider free surface span.

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“…The axial stress at failure (σ 1 ) under different confining pressures (σ 2 = σ 3 ) can be calculated by Equation (4). The results are shown in Table 1.…”

Section: Failure Surface Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on Rock Damage Mechanism for Lateral Blasting under High In Situ Stresses

et al. 2021

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“…The experimental apparatus mainly consisted of an electrical explosion experimental system, a static loading system, a measuring system, and a control system [41,42]. The photos of the experimental apparatus are shown in Figure 1.…”

Section: Experiments 21 Experimental Apparatusmentioning

confidence: 99%

Experimental Study on the Effects of In Situ Stress on the Initiation and Propagation of Cracks during Hard Rock Blasting

et al. 2021

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In situ stress is one of the most important factors affecting rock dynamic fractures during blasting excavation of deep rock mass that generally is hard rock. In this research, crater blasting experiments on hard rock under different uniaxial static stresses were conducted to investigate the initiation and propagation process of crack networks that were induced by coupled dynamic and static loads. Furthermore, the effects of anisotropic static stress fields on the initiation and propagation of crack networks during hard rock blasting, and the crack network morphological characteristics were analyzed and elucidated. The experimental results showed that the static stress field changed the process of crack network initiation and propagation during hard rock blasting, and then control the crack network morphology. Under uniaxial static stress, the crack network was elliptical with the long axis parallel to the static stress. In addition, the larger the anisotropic static stress is, the more obvious the elliptical morphology of the crack network. Moreover, the static stress lead to the delay of crack formation which indicates that the delay time during millisecond blasting excavation of deep rock mass should be adjusted appropriately according to the in situ stress. A stress-strength ratio (SSR) of 0.15 is the threshold value where static stress may have a significant effect on the initiation and propagation of a crack network. Meanwhile, the strain field prior to crack initiation during rock blasting controlled the morphological characteristics of the crack network. Finally, the mechanism of static stress affecting propagation and morphology of crack network was revealed theoretically.

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“…The test apparatus used in this study mainly consists of an electric explosion system, loading system, measurement system, and control system [21], as shown in Figure 1. The electric explosion system transforms electric energy into mechanical energy by utilizing the plasma explosion of wires and replaces the chemical explosion for rock blasting.…”

Section: Test Apparatusmentioning

confidence: 99%

Strain Field Evolution Characteristics of Free Surface during Crater Blasting in Sandstone under High Stress

et al. 2020

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Considering the problems related to hard rock blasting under high in-situ stresses at large depths, we conducted crater blasting tests on sandstone specimens under three static load conditions to investigate the strain field evolution of rock blasting under high stress. The digital image correlation (DIC) technique was used to monitor the evolution of the strain field on the free surface. Thus, the influence of the static stress on the blasting strain field was analyzed, and the formation mechanism of cracks on the free surface was elucidated. The results indicate that a circular tensile strain zone was formed without static loading. The direction of the maximum principal strain was perpendicular to the radius, which lead to the random emergence of multiple radial tensile cracks. Under a uniaxial static loading, an elliptical tensile strain zone was formed. The direction of the maximum principal strain was perpendicular to the static loading direction. This facilitated the initiation and propagation of tensile cracks preferentially in the direction parallel to the static loading. Under an equal biaxial static loading, the initial compressive strain in the specimen reduced the increment rate of the blasting strain, and restrained the formation of surface cracks. Besides, a determination method for dynamic tensile fracture strain of rock was proposed.

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Experimental study on rock-like materials fragmentation by electric explosion method under high stress condition

Cited by 26 publications

References 28 publications

Study on Rock Damage Mechanism for Lateral Blasting under High In Situ Stresses

Study on Rock Damage Mechanism for Lateral Blasting under High In Situ Stresses

Experimental Study on the Effects of In Situ Stress on the Initiation and Propagation of Cracks during Hard Rock Blasting

Strain Field Evolution Characteristics of Free Surface during Crater Blasting in Sandstone under High Stress

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