Damage Analysis of Concrete Structure under Multidirectional Shaped Charge Blasting Using Model Experiment and Ultrasonic Testing

Liu, Dunwen; Zhang, Jianjun; Tang, Yu; Jian, Yinghua; Cai, Caiwu

doi:10.1155/2021/6677041

Cited by 4 publications

(4 citation statements)

References 14 publications

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“…Shaped charge blasting fully utilizes the high compressive and low tensile properties of rocks to form tangential tensile stress. The coupling effect between the shaped charge tank and the explosive charge is perpendicular to the direction of the shaped charge [56,57]. Tangential tensile stress causes initial cracks on the wall of the blast hole.…”

Section: Bidirectional Shaped Charge Blastingmentioning

confidence: 99%

Multifractal Characteristics of Smooth Blasting Overbreak in Extra-Long Hard Rock Tunnel

Zhang,

Liu,

Tang

et al. 2023

Fractal Fract

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With the development of infrastructure construction in mountainous areas, the number of new extra-long tunnels is increasing. However, these tunnels often face the challenge of complex and variable surrounding rock grades, resulting in a large number of overbreak and underbreak due to the untimely adjustment of smooth blasting parameters. This study focuses on the optimization of the peripheral hole charging structure and blasting parameters for extra-long hard rock tunnels, aiming to improve the effectiveness of smooth blasting technology. The results of this study demonstrate a significant improvement in the effect of smooth blasting after implementing bidirectional polymerization blasting in the tunnel. A comparison between the bidirectional shaped charge and spaced decoupled charge blasting reveals that the former yields better results. To obtain accurate data on the tunnel section profile during excavation, a laser cross-section meter is used for measurement. Furthermore, this study quantitatively compares the optimization effect of smooth blasting parameters. The multifractal characteristics of the tunnel profile overbreak point sequences are analyzed under different smooth blasting schemes using the multifractal detrended fluctuation analysis (MF-DFA) method. It is found that both the spaced decoupled charge and the bidirectional shaped charge blasting exhibit multifractal features in the overbreak measurement point sequences. The calculation results of the multifractal features of the tunnel profile under different smooth blasting plans are in line with the actual situation.

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Section: Bidirectional Shaped Charge Blastingmentioning

confidence: 99%

Multifractal Characteristics of Smooth Blasting Overbreak in Extra-Long Hard Rock Tunnel

Zhang,

Liu,

Tang

et al. 2023

Fractal Fract

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“…In the aspect of slit blasting, Cheng Chen used high-speed laser schlieren system to conduct experimental research on the explosion wave of slit charge. Schlieren photos visually showed the change of external explosion wave flow field after slit charge explosion [6] . Chenxi Ding et al…”

Section: Introductionmentioning

confidence: 99%

Study on the effect of slit length of borehole on blasting effect

Jin,

Han,

et al. 2024

Preprint

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The dynamic caustics system combined with numerical simulation is used to study the effect of the slit in the borehole on the blasting effect. The result show that: slit blasting of the borehole has a significant directional fracture effect when compared with ordinary blasting, the length of cracks in the slit direction is significantly larger than that of ordinary blasting, and the length and number of cracks in the non-slit direction are significantly smaller than that of ordinary blasting. The slit in the borehole wall causes the blast energy to be released mainly in the slit direction and suppressed in the non-slit direction. Crack inhibition zone exists at the root of slit in the borehole wall. Once blasting produced the direction cracks in the slit direction, the surroundings of the blast hole wall will not produce cracks. Slit blasting can inhibit cracks near the slits, so as to achieve the purpose of controlling the direction of rock fracture. As the slit length increased, the major crack propagation length of the slits decreased before increasing. When the slit length increased to 5mm (diameter to length ratio of 1.2), the crack propagation length was the largest, then the slit length continued to increase, the crack extension length did not change much. With the increase of the slit length, the peak value of the slit main crack propagation stress intensity factor and the peak value of the velocity show the trend of decreasing and then increasing, and the two peak values are the lowest when the slit length is 3 mm. The horizontal incident tensile wave reflected by rock mass defects and blasthole unloading waves increase the stress intensity factor and crack propagation rate, promoting crack propagation. Considering the blasting effect, the cost and time of drilling slits, it is more appropriate to choose a slit length of 0.5mm (diameter to length ratio λ is 12). The research results provide a certain significance of guidance for the slit blasting of the borehole wall in practical engineering.

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“…et al [17,18] designed several sets of blasting model tests and a blasting plan ensuring the cutting effect was obtained. Liu D.W. et al [19,20] conducted rock-like material model tests, and the non-linear change law of rock mass damage and the advantages of V-shaped grooves were proposed. Qiu J.D.…”

Section: Introductionmentioning

confidence: 99%

Calculation Method of the Blasting Throwing Energy and Its Variation Affected by the Burden

et al. 2022

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Precise control of casting velocity and effective throwing kinetic energy conversion efficiency in blasting engineering are challenges. To provide a theoretical basis and reference for the implementation plan and fine construction of the cast blasting project, we study the problems of casting velocity and energy consumption ratio of broken rock under the impact load of explosions in this manuscript. The calculation methods of casting velocity and throwing energy of broken rock under two blasting modes of spherical charge and cylindrical charge are established by using the theory of dimensional analysis and rock breaking by blasting. A large number of model tests are carried out by using high-speed photography. The results indicate that the casting velocity of broken rock after explosive initiation has two evident stages: instantaneous acceleration to a certain value and subsequent fluctuation; the velocity presents an ordinary distribution law with the step height, and the fitting correlation of high-speed photography results is more than 91%. With the minimum burden increasing from 0.12 m to 0.2 m, the energy consumption decreases from 1306.88 J to 747.49 J and the proportion of energy consumption decreases from 14.77% to 8.45%.

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Damage Analysis of Concrete Structure under Multidirectional Shaped Charge Blasting Using Model Experiment and Ultrasonic Testing

Cited by 4 publications

References 14 publications

Multifractal Characteristics of Smooth Blasting Overbreak in Extra-Long Hard Rock Tunnel

Multifractal Characteristics of Smooth Blasting Overbreak in Extra-Long Hard Rock Tunnel

Study on the effect of slit length of borehole on blasting effect

Calculation Method of the Blasting Throwing Energy and Its Variation Affected by the Burden

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