Blast-Induced Damage on Millisecond Blasting Model Test with Multicircle Vertical Blastholes

Ma, Qinghai; Yuan, Pei-Xin; Zhang, Jingshuang; Ma, Ruiqiu; Han, Bo

doi:10.1155/2015/504043

Cited by 4 publications

(3 citation statements)

References 5 publications

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“…The test results are in good agreement with those of numerical simulation, indicating that the pressure-relief effect of the borehole can protect the wall materials and the bottom air gap columns. Ma et al [21] tested 4 types of millisecond blasting models with three-circle boreholes, aiming to find the blast damage on the surrounding rock in vertical shaft excavation and put forward effective damage control measures. Zhao et al [22] performed a blasting model test with similar materials and dosages by Froude scaling and provided theoretical and empirical references to the selection of materials and charging conditions for blasting test models.…”

Section: Shock and Vibrationmentioning

confidence: 99%

Theoretical Calculation and Experimental Analysis on Initial Shock Pressure of Borehole Wall under Axial Decoupled Charge

Lou

Wang

2018

Shock and Vibration

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This paper attempts to calculate the exact initial shock pressure of borehole wall induced by the blasting with axially decoupled charge. For this purpose, Starfield superposition was introduced considering the attenuation and superposition of blasting pressure, and the theoretical solution of initial borehole wall pressure was obtained for the upper and middle air-decked charging structures. Then, the explosive pressure field around the borehole was measured by cement mortar models and a dynamic pressure test system, and the pressures at multiple measuring points were simulated with numerical models established by ANSYS/LS-DYNA. The results show that the deviations between simulated and theoretical pressures are smaller than 10%, indicating the reliability of the theoretical formula derived by Starfield superposition. For the upper air-decked charging structure, the initial shock pressure of the charging section followed a convex distribution, with the peak value near the charge centre. With the increase in the distance from the charging section, the borehole wall shock pressure in the air gap underwent a sharp decline initially before reaching a relatively constant level. The minimum pressure was observed at the hole collar. For the middle air-decked charging structure, the pressures at both ends of the charging section obeyed a convex distribution, with the peak value near the charge centre. Finally, the author optimized air-decked charging structure of periphery boreholes within Grade III surrounding rocks of Banjie tunnel, China, and proved the enhancement effect of the theoretical findings on smooth blasting. The research findings provide valuable references to the theoretical and experimental calculation of air column length and other key parameters of air-deck blasting and shed new light on the charging structure determination of smooth blasting and blasting vibration control for the excavation of large-section, deep mining roadways.

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Section: Shock and Vibrationmentioning

confidence: 99%

Theoretical Calculation and Experimental Analysis on Initial Shock Pressure of Borehole Wall under Axial Decoupled Charge

Lou

Wang

2018

Shock and Vibration

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“…Ma Q.Y. 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.…”

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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“…General Particle Dynamics (GPD) method was put forward to study the zonal disintegration mechanism of deep rock mass in blasting excavation, and it was found that dynamic loads and high geostress are two dominant factors for occurrence of zonal disintegration [30]. Blasting excavation not only applies a dynamic load on deep rock masses but also induces blasting damage around an excavation [31,32]. By considering both high axial geostress and blasting load in deep rock masses, failure mechanism of zonal disintegration is investigated by elastic stress field analyses and modified Hoek-Brown criterion.…”

Section: Introductionmentioning

confidence: 99%

Zonal Disintegration Mechanism of Deep Rock Masses under Coupled High Axial Geostress and Blasting Load

Yuan

2018

Shock and Vibration

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Zonal disintegration phenomenon with alternative distribution of fracture zones and nonfracture zones is a characteristic failure in deep rock masses, especially for deep tunnel excavated by drill and blast method. To investigate the mechanism of zonal disintegration under coupled high axial geostress and blasting load, elastic stress field distribution for a circular tunnel in deep isotropic rock masses is obtained. Furthermore, Hoek-Brown criterion is amended by considering blast-induced damage effect. Both radial blasting load and blast-induced damage effect are assumed to decay in a negative exponential function. Taking the deep tunnel of Dingji coal mine in China as engineering background, the number and width of fracture zones are determined by deduced elastic stress field and modified Hoek-Brown criterion. Then numerical computation is conducted. Numerical computation results indicate that both the number and width of fracture zones mainly depend on high axial geostress and mechanical parameters of deep rock masses, and peak radial blasting load plays an important role in determining the width of fracture zone near the excavation.

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Blast-Induced Damage on Millisecond Blasting Model Test with Multicircle Vertical Blastholes

Cited by 4 publications

References 5 publications

Theoretical Calculation and Experimental Analysis on Initial Shock Pressure of Borehole Wall under Axial Decoupled Charge

Theoretical Calculation and Experimental Analysis on Initial Shock Pressure of Borehole Wall under Axial Decoupled Charge

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

Zonal Disintegration Mechanism of Deep Rock Masses under Coupled High Axial Geostress and Blasting Load

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