Numerical investigation on crack propagation and coalescence induced by dual-borehole blasting

Chuan-jin, PU; Yang, Xin; Zhao, Han; Chen, Zhenlin; Xiao, Dingquan

doi:10.1016/j.ijimpeng.2021.103983

Cited by 29 publications

(16 citation statements)

References 50 publications

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“…where E g is the bursting energy of high-pressure gas, J; P 1 is the absolute pressure of high-pressure gas, Pa; V is the volume of high-pressure gas, m 3 ; R is the adiabatic index of gas, and the adiabatic index of air is 1.4; P 2 is the standard atmospheric pressure, which is 101,325 Pa. The TNT equivalent for the same energy is calculated using the energy equivalent formula, which is expressed as W TNT = E g /q TNT (11) where q TNT is the explosion energy of 1 g of TNT and takes the value of 4250 J/g. In this paper, the energy released by the HPAB is calculated as 75.67 J by Equation (10).…”

Section: Calculation Of Explosive Equivalentsmentioning

confidence: 99%

“…In this paper, the energy released by the HPAB is calculated as 75.67 J by Equation (10). Then, the energy released by the HPAB is substituted into Equation (11), and the corresponding TNT equivalent is calculated as 0.018 g.…”

Section: Calculation Of Explosive Equivalentsmentioning

confidence: 99%

“…Numerical simulation is an important tool to study stress evolution and crack propagation during blasting [9][10][11]. Zhu et al [12] investigated the gas drainage and crack propagation of concrete sample under the action of HPAB by using COMSOL (Version 3.5, COMSOL, Stockholm, Sweden).…”

Section: Introductionmentioning

confidence: 99%

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Study on the Stress Field and Crack Propagation of Coal Mass Induced by High-Pressure Air Blasting

et al. 2022

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High-pressure air blasting (HPAB) is one type of physical blasting technique that enhances the extraction rate of coalbed methane by impacting the coal mass with high-pressure gas to create cracks within it. First, based on the physical and mechanical parameters of the simulated coal rock mass, the RHT constitutive model of the coal rock mass was established, and its parameters were determined. Then, the laws of crack propagation and stress wave decay in coal induced by high-pressure air blasting were revealed by comparing the effect with that of equivalent explosive blasting. Next, the HPAB experiment was simulated to explore the coal crack propagation law under in-situ stress conditions. Finally, the HPAB experiment was carried out and the results of this experiment were compared with the numerical simulation results. The results indicate that the crack propagation induced by high-pressure air blasting is considered as two major stages, i.e., the crack initiation and crack propagation stage induced by the stress wave and the crack stable propagation stage induced by the duration high-pressure gas. In the case of equal energy, the peak stress wave of high-pressure gas is smaller, decays more slowly and has a longer action time, compared to explosive blasting. Therefore, the number of initial random cracks in coal mass induced by high-pressure air blasting is less, and the range of crack propagation induced by high-pressure air blasting is larger. When λ = 0 (λ is the ratio of the horizontal in-situ stress to the vertical in-situ stress), the in-situ stress in the coal seam can promote the propagation of vertical cracks but inhibit the propagation of horizontal cracks. When λ = 0.5 and 1, the in-situ stress inhibits the propagation of both horizontal and vertical cracks.

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Section: Calculation Of Explosive Equivalentsmentioning

confidence: 99%

Section: Calculation Of Explosive Equivalentsmentioning

confidence: 99%

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Study on the Stress Field and Crack Propagation of Coal Mass Induced by High-Pressure Air Blasting

et al. 2022

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“…Yang L. et al (2020) found that compared with single-hole blasting, double-hole blasting had a superposition effect, and the peak strain and stress at the midpoint of the blasthole were more than twice that of singlehole blasting. Pu et al (2021) found that, by using numerical simulation method, increasing the spacing of blastholes was not conducive to the propagation of cracks, but also inhibited the merging of cracks at the guide holes. Wu et al ( 2021) also compared the crack behavior of elliptical bipolar linear charge blasting and ordinary blasting based on numerical simulation method, and found that the charging mode had a great impact on the formation of directional cracks.…”

Section: Introductionmentioning

confidence: 99%

Study on rock mass failure characteristics of double-hole delayed blasting in interbedding based on particle expansion algorithm

et al. 2023

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The existence of the interface between soft and hard rock often makes it difficult to control the blasting effect. Studying the influence of structural plane and delayed initiation time on rock blasting characteristics can make the blasting effect more controllable. In this paper, by using the Particle Flow Code (PFC2D) and particle expansion algorithm, the double-hole delayed blasting experiments of soft-hard rock are carried out, and the results are analyzed from the perspectives of fragment gradation, micro contact force and energy field. Results show that: 1) When blasting in hard rock, if the distance between structural plane and blasthole is about two times the radius of crushing area, it will easier to form large area fragments, and the fragments tend to be crushed with the increase of the distance. When the distance is 2–4 times the radius of crushing area, with the increase of delay time, the overall fragment area value increases first and then decreases, and reaches the maximum when the delay time is 4 ms. 2) When the structural plane existing in the rock mass, the delayed initiation will make the contact force become relatively uniform within a certain range. The main direction of contact force will appear in the uneven state of contact force generated by simultaneous or delayed initiation, which is close to the parallel or vertical direction of blasthole connection. 3) When blasting in hard rock, if the distance between the structural plane and the blasthole is greater than about two times the radius of the crushing area, compared with simultaneous blasting, the peak kinetic energy and peak strain energy of delayed blasting will be reduced by about 33% and 46% respectively.

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“…These models require many additional material parameters that can be difficult to acquire for in situ rocks, but nonetheless have recently been used in the modelling of blasts to improve their predictive capabilities. 19,21,22 Banadaki 14 performed a number of blasting experiments on granitic rocks, providing images and quantitative characterisation of the resulting fracture patterns. Fracturing during a blast is driven by blast wave propagation and gaseous expansion.…”

Section: Introductionmentioning

confidence: 99%

Modelling of fracture intensity increase due to interacting blast waves in three-dimensional granitic rocks

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et al. 2023

International Journal of Rock Mechanics and Mining Sciences

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Numerical investigation on crack propagation and coalescence induced by dual-borehole blasting

Cited by 29 publications

References 50 publications

Study on the Stress Field and Crack Propagation of Coal Mass Induced by High-Pressure Air Blasting

Study on the Stress Field and Crack Propagation of Coal Mass Induced by High-Pressure Air Blasting

Study on rock mass failure characteristics of double-hole delayed blasting in interbedding based on particle expansion algorithm

Modelling of fracture intensity increase due to interacting blast waves in three-dimensional granitic rocks

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