Analysis on the impact pressure on blast hole wall with radial air-decked charge based on shock tube theory

Lou, Xiaoming; Zhou, Ping; Yu, Jin; Sun, Mingwu

doi:10.1016/j.soildyn.2019.105905

Cited by 16 publications

(8 citation statements)

References 12 publications

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“…However, the internal part of the water medium is not enough to form an interface to weaken the shock wave, and the calculation result will be much more enhanced than the attenuation occurred. From the pressure curve of the blasthole plotted by experiment (Lou et al, 2020), the blasthole pressure would significantly reduce for every increase of 0.5 in the decoupled coefficient, so the decoupled coefficient η is introduced. Assume that η endures an attenuation for every increase of 0.5 (starting from 1).where R is the radius of the blasthole and r is the radius of the explosive.…”

Section: Attenuation Of Blasthole Pressure In the Scenario Of Water-c...mentioning

confidence: 99%

“…Many researchers calculated the blasthole pressure and crack length by referring to the experimental findings and data: Xiaoming Lou (Lou et al, 2020) engaged in model blasting test on a thick-walled concrete cylinder with strain bricks, calculated the peak blasting stress according to the strain equation, and further considered the correlation between peak stress and air radial decoupled coefficient; Li Yuan Chi (Chi et al, 2019) used a self-engineered cylinder and pressure gauge to study the shock wave pressure applied on granite and the attenuation of pressure, and derived the exponential function applicable to the pressure of shock wave on granite and the attenuation of pressure by fitting the experimental data curves; Wei Yuan (Yuan et al, 2019) observed the effects of water-coupled charge structure on the attenuation and distribution of blasting stress by combining physical model experiment and numerical simulation and considering the ion amplitude changes of stress wave along the radial direction; Zhiheng Wang (Wang et al, 2021) examined the cracking mechanism and propagation tendency in respect of different types of cracks by conducting acoustic emission tests of rock specimens and considering the propagation characteristics of sound waves in cracks; Xiaohan Li (Li et al, 2021) employed a crack propagation instrument and strain gauge to monitor relevant data of blasting stress wave propagation, in order to analyze the stress distribution and fracture mode in rocks under the action of blasting stress wave; Lei Zhou (Zhou et al, 2018) used a strain gauge to detect the fracture time and crack velocity in the course of dynamic loading test; and Wan Duanying (Wan et al, 2019) studied the propagation behavior of Type I crack under explosive load by testing uniform and transparent organic glass specimens, divided it into steady propagation stage and unsteady propagation stage, and further analyzed the extent of roughness of cracks in each stage.…”

Section: Introductionmentioning

confidence: 99%

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Attenuation of hole wall pressure and the prediction model for crack length in the scenario of blasting with water-coupled medium

Wang

Yang

et al. 2023

Journal of Vibration and Control

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For fixing the parametric design problem of blasting with water-coupled medium and improving the rock breaking quality, efforts should be made to quantify and examine the blasthole pressure and the explosive crack growth length in the scenario of blasting with water-coupled medium. The water medium was treated as an ideal fluid on the precondition that its flow velocity and internal energy would change continuously with time. Under the elastic wave theory and combining the propagation law of shock wave in water and rock or rock-like medium, the pressure, velocity, and other parameters in relation to shock wave at the interface between explosive and water, in the water medium, and in the peripheral medium after the occurrence of transmission and reflection at the interface between water and hole wall, were subject to theoretical calculations. As a result, the equation for the peak blasthole pressure in the scenarios of explosive and hole wall medium parameters was derived. Further considering the weakening effect of sparse wave on shock wave and the effect of multiple reflections superimposed on shock wave by the hole wall medium, the equation for the attenuation of blasthole pressure as a function of the time constant T was obtained. Next, the prediction model for crack length in the scenario of blasting with water-coupled medium was constructed by the aforementioned equation for calculation of blasthole pressure in the scenario of blasting and according to the model for explosive gas-driven one-dimensional crack growth. Finally, the blasthole pressure and one-dimensional crack length applicable to the explosive and hole wall medium parameter with decoupled coefficients of 1.33, 1.67, 2.00, 2.67, and 3.33 at a given time point were examined by combining the derived equations for theoretical calculations and numerical simulations. Results showed that in the scenario of blasting with water-coupled medium, the blasthole pressure would reduce as the decoupled coefficient η increases, and it is significantly influenced by η, up to 25% even above 50%. Similarly, the crack length would reduce as the decoupled coefficient η increases, but it is slightly influenced by η, only at 15% or so in general.

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Section: Attenuation Of Blasthole Pressure In the Scenario Of Water-c...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Attenuation of hole wall pressure and the prediction model for crack length in the scenario of blasting with water-coupled medium

Wang

Yang

et al. 2023

Journal of Vibration and Control

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“…Some scholars have also conducted intensive research on the different charge structures of columnar drug packs. rough different positions and proportions of air deck, the action time in the cylindrical charge hole is extended to improve the utilization rate of explosives and reduce the blasting vibration [25][26][27][28][29].…”

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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“…Andrievskii [22] optimized the parameters for drill-and-blast operation chart in mining with direct slot stage cutting. In addition, Qiao et al [23,24] research on optimization algorithms, wave transformation, and hybrid model prediction of improved deep learning, Lou et al [25,26] research on impact pressure on blasthole wall with radial air-decked charge, and so on obviously have better parameter value for blasting parameter optimization.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and Numerical Research on V‐Cut Parameters and Auxiliary Cuthole Criterion in Tunnelling

Lou

Bao

et al. 2020

Advances in Materials Science and Engineering

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This paper aims at providing a sound theoretical solution to auxiliary central hole and the cutting parameters. For this purpose, the forming mechanism of V-cut cavity for cutting blasting was performed based on the hypothetical rock breaking mechanism of V-cut blasting. A theoretical solution for increasing the critical depth of the auxiliary center cuthole and the criteria for increasing the cuthole diameter of various types of cutholes when the rock attributes, explosive properties, and cuthole dip angle are constant are proposed. (1) If charging length le < 0.75H/sin θ, no auxiliary cuthole is needed. (2) If 0.75H/sin θ < le < 0.75H/sin θ + (2∼4) × 0.1, a central vertical auxiliary hole is needed. (3) If 0.75H/sin θ + (2∼4) × 0.1 < le < 0.75(H/sin θ + Hi/sin θi), a shallow inclined hole is needed. (4) If le > 0.75(H/sin θ + Hi/sin θi), both the central vertical cuthole and the shallow inclined cuthole are needed. Meanwhile, the theoretical solution was verified by numerical modelling with ANSYS/LS-DYNA. Moreover, the field implementation of the V-cut and the auxiliary hole effectively improved the blasting effect in both efficiency and economy.

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Analysis on the impact pressure on blast hole wall with radial air-decked charge based on shock tube theory

Cited by 16 publications

References 12 publications

Attenuation of hole wall pressure and the prediction model for crack length in the scenario of blasting with water-coupled medium

Attenuation of hole wall pressure and the prediction model for crack length in the scenario of blasting with water-coupled medium

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

Theoretical and Numerical Research on V‐Cut Parameters and Auxiliary Cuthole Criterion in Tunnelling

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