Effect of double holes on crack propagation in PMMA plates under blasting load by caustics method

Li, Chengxiao; Kang, Yiqiang; Luo, Haohao

doi:10.1016/j.tafmec.2021.103103

Cited by 22 publications

(3 citation statements)

References 28 publications

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“…In engineering, multi-hole blasting is often used, so the interaction between blastholes needs to be considered. At present, the researches on double-hole or multi-hole initiation mainly focus on the blasthole spacing (Li C. et al, 2021), in-situ stress (Yang J. et al, 2020), initiation delayed time (Chen et al, 2017), and charging method (Guo et al, 2020). 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.…”

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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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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“…Hence, interaction of blastholes is always inevitable. Nowadays, the research on double-hole initiation or group-hole initiation chiefly focuses on distance of blastholes 5 , in-situ stress 6 , delay time 7 and charging mode 8 . By comparing the model test results of single-hole and double-hole initiation, Yang et al 9 believed that, at the midpoint of two blastholes, the peak strain in double-hole blasting is 2.4–2.7 times that of single-hole blasting, and the stress superposition effect of double-hole blasting is much greater than 2.…”

Section: Introductionmentioning

confidence: 99%

Cracks propagation characteristics of double-hole delay blasting in soft-hard composite rock mass

Cui

Xie

Qin

et al. 2023

Sci Rep

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By researching the distance between blasthole and interface of soft-hard rock strata, as well as the time of delay detonation, blasting effect of the rock mass will be more controllable. Firstly, validity of numerical method was authenticated from three angles: blasting coupled stress field, ratio of crushing zone radius to blasthole radius, and crack network state. Under the condition of soft-hard rock strata, numerical model of double-hole blasting was established by using PFC2D. Then delay blasting experiments were carried out under different relative positions of blasthole and interface. Ultimately, results were analyzed from three perspectives: crack network, crack quantity and rock fragment. Results show that: (1) When detonated in hard rock, if between interface and blasthole distance is greater than twice crushing zone radius, the closer blasthole is to the interface, the more obvious the “hook” phenomenon between the two blastholes is. With increasing delayed initiation time, “hook” phenomenon will weaken or even disappear. (2) Based on the crack information initiated in hard rock, the law of crack number varying with thickness of hard rock and delay time is obtained. (3) For initiation in hard rock, crack extension range is large, but less fragments are formed. The law is opposite to that initiation in structural plane and soft rock. Fragmentation area increases exponentially with increasing soft rock thickness, and exponential function is obtained.

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“…Such events are widespread and are triggered by a variety of causes. The causes of cooking-gas explosions in residential neighborhoods are stipulated by a range of interconnected factors (circumstances) of a technical or regulatory nature or involve human factors [1][2][3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Specifics of Explosion-Venting Structures Providing Acceptable Indoor Explosion Loads

et al. 2021

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This article experimentally and theoretically demonstrates that the presence of blast-relief openings (windows) equipped with explosion-venting structures (EVS) allows explosive pressure to be reduced to a safe level (2–4 kPa). We provide results of model and full-scale experiments aimed at studying the influence of EVS parameters of blast-relief openings in explosion-hazardous buildings on the intensity of explosive loads. It was demonstrated that the maximum explosive-pressure value inside EVS-equipped buildings depends on the EVS start-to-open pressure, the structure’s response rate (lag), and characteristic dimension of the premises. Thus, each particular building requires individual selection of EVS parameters, which provide a safe level of excessive pressure in case of an explosive accident. This aspect, however, prevents the widespread use of EVS at explosion-hazardous sites. This article offers an modest upgrade of the explosion-venting structure that provides an indoor pressure equal to the EVS start-to-open pressure. The suggested innovation excludes the possibility of a significant increase in explosive pressure due to an EVS response delay. The efficiency of the suggested technical upgrade was proven by numerical experiments and indirectly by experimental studies aimed at exploring the physical processes associated with the opening of EVSs after an explosion accident. The use of upgraded EVSs will allow for provision of a known maximum level of the explosion load should an explosion event occur in an EVS-equipped room.

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Effect of double holes on crack propagation in PMMA plates under blasting load by caustics method

Cited by 22 publications

References 28 publications

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

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

Cracks propagation characteristics of double-hole delay blasting in soft-hard composite rock mass

Specifics of Explosion-Venting Structures Providing Acceptable Indoor Explosion Loads

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