Experimental and numerical studies of the blast-induced overbreak and underbreak in underground roadways

Hong, Zhixian; Tao, Ming; Cui, Xili; Wu, Chengqing; Zhao, Minghui

doi:10.1016/j.undsp.2022.04.007

Cited by 32 publications

(4 citation statements)

References 32 publications

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“…DIF c = (DIF t −1)(T/ f c ) + 1 (10) in which, DIF t and DIF c are the dynamic increase factor for tension and compression, respectively. W x , S, F m , W y are the fitting constants, the values of W x = 1.6, S = 0.8, F m = 10, W y = 5.5 are determined referred the research of Tedesco et al [33],…”

Section: Strain Rate Effect Modelmentioning

confidence: 99%

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Influence of In-Situ Stress on Cut Blasting of One-Step Raise Excavation Using Numerical Analysis Based on a Modified Holmquist-Johnson-Cook Model

et al. 2023

Materials

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Due to different tensile and compressive properties of rock material, the corresponding tensile and compressive damage evolution show major differences. To investigate the tensile and compressive damage evolution in deep cut blasting with different in-situ stresses, an improved Holmquist-Johnson-Cook (HJC) material model considers the tensile and compressive damage separately is developed. The improved HJC model is implemented into LS-DYNA via a user-defined subroutine in this study. Then, a numerical model with different in-situ stresses loading schemes is modelled. Numerical simulation results show that in-situ stress can inhibit the development of tensile damage evolution, while promote the development of compressive damage evolution. The overall damage zone presents a decreasing trend with the increase of in-situ stress, because the tensile damage is more sensitive than the compressive damage for rock material. In addition, the maximum principal stress can determine the development of the direction of damage. Further, for a field test of blind cut raise in deep, the actual in-situ stress values are loaded on the numerical model. Then, in order to overcome the difficulties caused by in-situ stress, the cut blasting design is optimized by reducing hole spacing. Subsequently, the optimized cut parameters are applied in the blind cut raise. However, the one-step raise excavation method is adjusted to two steps to ensure success due to a serious borehole deviation between drilling and design drawing. After these steps, the formation of the blind cut raise with 8.7 m depth is met the requirements of design.

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Section: Strain Rate Effect Modelmentioning

confidence: 99%

“…In recent years, many studies on damage evolution of rock mass under blasting loading have been conducted [10,11]. Liu and Katsabanis [12] described a constitutive model for predicting rock damage and fragment size distribution based on continuum mechanics and statistical fracture mechanics.…”

Section: Introductionmentioning

confidence: 99%

Influence of In-Situ Stress on Cut Blasting of One-Step Raise Excavation Using Numerical Analysis Based on a Modified Holmquist-Johnson-Cook Model

et al. 2023

Materials

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“…Drilling and blasting technology is widely used in rock engineering, such as tunneling and underground chamber excavation, due to low cost and high efficiency [5,6]. With the increasing of the in situ stress in rock engineering projects, the drilling and blasting are faced with severe challenges, such as unmanageable blast-induced damage cracking and insufficient fragmenting, so sustainable development of deep rock engineering is limited [7][8][9][10]. Therefore, it is essential to enrich the understanding of blast-induced damage cracking of high-stress rock mass for improving blasting efficiency in deep projects.…”

Section: Introductionmentioning

confidence: 99%

Effects of Confining Stress on Blast-Induced Damage Distribution of Rock with Discontinuity

Pan,

Wang,

Zhou

et al. 2023

Sustainability

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Discontinuous rock mass, such as joints and fractures, have a great influence on the blasting quality and sometimes induce additional damage at the discontinuity. In deep rock engineering, high in situ stress makes the damage mechanism of rock with discontinuity under blasting loading more complicated. Quantitative analysis of blast-induced damage in discontinuous rock under high in situ stress is of great importance in guiding the fine blast design. In this paper, a series of numerical models have been established to quantitatively investigate the effect of confining stress and inclination angle on blast-induced damage of rock with discontinuity. The numerical results show that the discontinuity obviously changes the distribution mode of blast-induced damage, and there is more damage near the discontinuity. The blast-induced damage crack length of discontinuous rock decreases as hydrostatic stress rises. Under non-hydrostatic stress, the damage crack propagation appears to have a higher tendency in the higher confining stress direction. In addition, the inclination angle of discontinuity will affect the damage distribution of rock with discontinuity. The fragmentation degree is greatest when the discontinuity is perpendicular to the direction of higher confining stress. Due to the presence of discontinuity, the guiding effect of higher confining stress on damaged cracks is weakened. The results provide a reference for the tunnel fine-blasting design of rock with discontinuity.

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“…Stemming length is a crucial parameter in blasting design, and its rational application to enhance energy utilization has been substantiated in various studies [8][9][10]. Compared to non-stemming, appropriate stemming facilitates the retention of a more significant portion of blast energy and prolongs the duration of waves within the blast hole, consequently improving rock fragmentation efficiency and reducing under-break extents in tunnels induced by blasting [11][12][13][14]. Furthermore, stemming length influences blast performance and directly impacts fly-rock and ground vibrations [15,16].…”

Section: Introductionmentioning

confidence: 99%

Experiment Study of Stemming Length and Stemming Material Impact on Rock Fragmentation and Dynamic Strain

Shi,

Zhang,

Qiu

et al. 2023

Sustainability

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Stemming length and stemming materials are crucial factors in blasting design, which affect the sustainability of mining. This study investigates the influence of stemming length and stemming material on rock fragmentation, stemming recoil, and surface strain response through 15 small-scale model blasting tests. The results indicate that when using clay as a stemming material, increasing the stemming length facilitates rock fragmentation and reduces the stemming recoil area. The strain measurements show that both tensile and compressive strain peaks on the blasting crater surface increase with the growth of stemming length, while the strain peaks on the upper surface decrease. A comparative analysis of different stemming materials reveals that clay performs the best, exhibiting the highest total weight of fragments, blasting crater size, and fragmentation energy utilization. Strain results indicate that clay stemming generates more significant strain peaks and higher strain loading rates on the blasting crater surface, favoring a more concentrated application of explosive energy on the crater surface and improving rock fragmentation. Sand + clay stemming yields fragments more concentrated in medium-sized particles than clay stemming. If the blasting goal is to increase the utilization efficiency of explosive energy and reduce the hazards of stemming recoil, it is recommended to use clay stemming. In addition, if uniform fragmentation is desired (reducing large and fine particles), a combination of sand + clay stemming can be used. These findings have practical implications for optimizing blasting design and engineering applications.

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Experimental and numerical studies of the blast-induced overbreak and underbreak in underground roadways

Cited by 32 publications

References 32 publications

Influence of In-Situ Stress on Cut Blasting of One-Step Raise Excavation Using Numerical Analysis Based on a Modified Holmquist-Johnson-Cook Model

Influence of In-Situ Stress on Cut Blasting of One-Step Raise Excavation Using Numerical Analysis Based on a Modified Holmquist-Johnson-Cook Model

Effects of Confining Stress on Blast-Induced Damage Distribution of Rock with Discontinuity

Experiment Study of Stemming Length and Stemming Material Impact on Rock Fragmentation and Dynamic Strain

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