Effects of confining pressure on crater blasting in rock-like materials under electric explosion load

Peng, Jun; Zhang, Fengpeng; Du, Chuan; Yang, Xiaohui

doi:10.1016/j.ijimpeng.2020.103534

Cited by 40 publications

(11 citation statements)

References 55 publications

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“…Therefore, the anisotropy of the crack network is positively correlated with the anisotropy of static stress. Yi et al [29] and Peng et al [30] also obtained the same experimental results by a serious of experiments. The above experimental results indicate that the blast hole spacing should be properly adjusted based on the in situ stress.…”

Section: Effects Of Static Stress On the Morphological Characteristics Of The Crack Networksupporting

confidence: 57%

“…Under uniaxial static compressive stress, the cracks that are produced by explosion dynamic load tend to propagate along the axis of the direction of the static compressive stress [26][27][28]. In addition, Yi et al [29] and Peng et al [30] found, by using numerical experiments, that the higher the uniaxial static compressive stress, the longer the distance of crack propagation. However, under a triaxial static compressive stress, the number of cracks that are induced by dynamic loads will greatly reduce, as will the degree of damage to the rock [31,32].…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Effects Of Static Stress On the Morphological Characteristics Of The Crack Networksupporting

confidence: 57%

Section: Introductionmentioning

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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“…The work studied the crater blasting under different confining pressures through theoretical analysis and physical model tests. Under the condition of the uniaxial load, the shape of the crater in the long axial loading direction was elliptical with the increase in the confining pressure, and the opening angle and pit volume in this direction increased (Peng et al, 2020;Zhang et al, 2021). Some experiments and numerical simulation studies were carried out on rock blasting under high ground stress (Li et al, 2021;Jayasinghe et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Fracturing Characteristics of Double-Hole Blasting Under Static Stresses

et al. 2022

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This study aims to investigate the fracturing characteristics of double-hole blasting under the action of coupled static stress and delayed time explosion. A total of thirteen explosive tests were carried out on rectangular concrete blocks with different constraints. The test blocks were wrapped in steel mesh in the test bed to prevent flying away of the cracked blocks after blasting. After blasting, the surface area of the crater was measured, and all pieces of the cracked blocks were collected, screened, and analyzed. The experimental results show that (1) the shape of free-surface craters was affected by static stress. The surface area and overall volume of the craters increased in the direction of loading stress. (2) The crater under simultaneous initiation was larger than that under delayed initiation when the tested block had a single free surface. (3) The fragmentation of blasting is closely related to the static confining pressure and delay initiation applied on the tested specimens. It is believed that this research will contribute to the design of multi-hole blasting in the deep geological body in the respect of the theoretical analysis.

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“…According to Livingston's blasting funnel theory, loosening blasting is a kind of blasting technology that breaks the medium without throwing [5]. By adjusting the spacing parameter, the blasting effect can be improved and the unit consumption of explosives can be reduced.…”

Section: Introductionmentioning

confidence: 99%

Optimization and Application of Spacing Parameter for Loosening Blasting with 24‐m‐High Bench in Barun Open‐Pit Mine

Zhang

Wang

et al. 2021

Shock and Vibration

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In view of the near slope blasting in Barun open-pit mine, which has merged sublevel mining, the operation safety conditions of middle-sized and large equipment in the second phase expansion are poor and need urgent improvement. To increase the efficiency of expansion and reduce costs, a 24-m-high bench and large spacing parameter for loosening blasting are proposed. The analysis of the physical mechanism of the stress wave attenuation in the rock indicates that the cylindrical charge is equivalent to several spherical charges. Considering the pressure attenuation, reflection, transmission, and superposition of the spherical charge after the equivalence, a double exponential function correction equation of the stress wave attenuation is obtained based on the Mises strength criterion. The stress of any point in the rock medium with various spacing parameter is obtained by calculation. ANSYS/LS-DYNA was used to simulate and study the stress distribution of a 24-m-high bench with various spacing parameter. Meanwhile, the accuracy of the correction equation was verified. The parameters of the high-bench blasting with good effect and low cost were determined to be 15 m × 5.5 m, and field tests were carried out. Results show that the large spacing parameter for 24-m-high bench loosening blasting in Barun open-pit mine is efficient and economical in medium-hard rock blasting. This study provides a reference for the practical exploration of the expansion of high benches in open-pit mines in China. The calculation error of the corrected double exponential function is near the numerical simulation result. It is suitable for all kinds of professional designers.

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Effects of confining pressure on crater blasting in rock-like materials under electric explosion load

Cited by 40 publications

References 55 publications

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

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

Experimental Study on Fracturing Characteristics of Double-Hole Blasting Under Static Stresses

Optimization and Application of Spacing Parameter for Loosening Blasting with 24‐m‐High Bench in Barun Open‐Pit Mine

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