Numerical Simulation of Rock Mass Structure Effect on Tunnel Smooth Blasting Quality: A Case Study

Wang, Jianxiu; Cao, Ansheng; Liu, Jiaxing; Wang, Huanran; Liu, Xiaotian; Li, Huboqiang; Sun, Yiying; Long, Yanxia; Wu, Fan

doi:10.3390/app112210761

Cited by 6 publications

(5 citation statements)

References 30 publications

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“…Generally, the tensile strength of rocks was much smaller than the compressive strength, and cracks occurred along the connection between the two holes. This finding was consistent with the principle of smooth blasting studied by many researchers in the literature [35]. At the same time, compared to the hole-by-hole blasting method, the effective stress and displacement generated in front of the blast hole were relatively large under the three-hole simultaneous blasting method.…”

Section: Resultssupporting

confidence: 89%

Experimental and Numerical Study on the Effect of Three-Hole Simultaneous Blasting Technology on Open-Pit Mine Bench Blasting

Zhang,

Li,

Wei

et al. 2024

Applied Sciences

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Blasting technology is widely applied in various engineering applications due to its cost-effectiveness and high efficiency, such as in mining, transport infrastructure construction, and building demolition. However, the occurrence of cracking in the rear row has always been a major problem that disrupts mining bench blasting. To address this issue, a three-hole simultaneous blasting technology is proposed in this study. Both numerical simulations and onsite blasting experimental testing were conducted. To aid this endeavor, the three-hole simultaneous blasting and the hole-by-hole blasting methods were adopted to comparatively analyze the severity of the damage caused to the original rock and the effect of rock fragmentation in the rear row. The obtained results highlighted that the outcome of the blast produced by the three-hole simultaneous blasting method is satisfactory, with fewer flying stones and concentrated blasting piles required. Additionally, the original rock in the rear row showed no obvious sign of tensile damage and had uniform fragmentation. It was also found that a block size of less than 60 cm accounts for 100%, while a block size of less than 50 cm accounts for 98.7% of the whole blocks, with no large blocks reported. Moreover, a penetrating horizontal crack occurred in the direction of the connection of the blast hole center when the three-hole simultaneous blasting method was adopted. This resulted in a smooth and flat rear part of the rocks at the interface. Compared to the hole-by-hole blasting method, the three-hole simultaneous blasting method improved the effective stress and displacement at each measurement point. At the measurement point directly at the front of the borehole, the maximum effective stress attained 67.9 GPa, and the maximum displacement reported was 31.9 cm. Overall, it was shown that the three-hole simultaneous blasting technology is applicable in similar applications of mine bench blasting, which is conducive to addressing the rear row original rock strain for onsite bench blasting.

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Section: Resultssupporting

confidence: 89%

Experimental and Numerical Study on the Effect of Three-Hole Simultaneous Blasting Technology on Open-Pit Mine Bench Blasting

Zhang,

Li,

Wei

et al. 2024

Applied Sciences

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“…Position 5, Position 6, and Position 7: www.nature.com/scientificreports/ When the joint surface is located between two peripheral holes, the explosion stress wave has a large attenuation effect on the joint surface, so the over-excavation phenomenon near these positions is effectively controlled. In summary, the relative position of the joint surface and the peripheral holes will have a great impact on rock mass damage, and on over-excavation and under-excavation 50,51 , which can be overcome by increasing or decreasing the charge.…”

Section: Discussionmentioning

confidence: 99%

“…The No. 2 rock emulsion explosive is used for the on-site blasting, the density of the explosive is 1.24 g/cm 3 , the detonation speed is D = 4200 m/s, the diameter of the blast hole is 42 mm, and the diameter of the cartridge is 32 mm. www.nature.com/scientificreports/ Peripheral holes are equipped with 1.5 cartridges, the charge length l c is 0.45 m, and the blast hole length l b is 1.4 m. Calculated using Eq.…”

Section: Numerical Simulationmentioning

confidence: 99%

“…A reasonable arrangement of peripheral holes is an effective means to control the over-excavation and under-excavation in tunnel blasting. Wang et al 3 established a numerical analysis model of tunnel smooth blasting using LS-DYNA software. By comparing the results of numerical simulation and field monitoring, it was shown that the spacing of peripheral holes should be mainly considered in the massive structure and the fractured structure.…”

Section: Introductionmentioning

confidence: 99%

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Calculation of hole spacing and surrounding rock damage analysis under the action of in situ stress and joints

Tian

Tao

Liu

et al. 2022

Sci Rep

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In situ stress and joints have a significant impact on the propagation and attenuation pattern of blast stress waves, and they are two important factors that must be considered for tunnel blasting hole network deployment. This paper proposes a blast stress wave attenuation equation and a peripheral hole distance calculation method under the combined action of in situ stress and joints. First, the static and dynamic parameters of the jointed slate are obtained by drilling core samples in the field and conducting indoor tests. Next, considering the geometric and physical attenuation of the blast stress wave, the attenuation formula of the blast stress wave under the combined action of in situ stress and joints is derived. Based on the theory of the combined action of stress waves and explosive gas, a formula for calculating the peripheral hole distance that integrates the effects of in situ stress, joints, and tensile strength of the rock body is proposed. Finally, LS-PREPOST software is used to analyze the damage to the surrounding rock, verified by an on-site blasting test. The results show that the blast stress wave attenuation formula proposed in this paper can accurately predict the stress wave peak value under the combined action of in situ stress and joints. Combining the geological conditions and blasting parameters of the Bayueshan Tunnel study section, the optimal peripheral hole spacing is calculated to be 45 cm. The average over-excavation value of the grade IV surrounding rock is controlled within 22 cm and the over-consumption of concrete per linear meter is controlled within 100% using the peripheral hole layout method and the hole network layout parameters proposed in this paper. The research results provide a reference for the control of over-excavation and under-excavation in large-section tunnel blasting.

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“…To ensure a clear understanding of the influence of each factor on the mechanical factors, we divided each factor into five grades. We combined this with the orthogonal test scheme used in previous investigations on rock-like materials [33,34]. Table 2 presents the orthogonal test scheme for the sandstone-like material ratio, while Table 3 shows the orthogonal test scheme for four factors and five levels.…”

Section: Orthogonal Test Of Rock-like Materialsmentioning

confidence: 99%

Investigation of Sandstone-like Material for Damaged Rock Mass Based on Orthogonal Experimental Method

Wang,

Xie,

Song

et al. 2024

Buildings

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The investigation of the mechanical properties of rock mass can be effectively carried out through rock-like material experiments. In this study, polystyrene foam particles were utilized as a novel material for simulating initial damage within rocks. Our research involved the development of sandstone-like materials with comparable mechanical properties to actual sandstone. These materials were then subjected to orthogonal mechanical tests, allowing us to identify the key factors that have a substantial impact on the mechanical parameters of sandstone-like rocks. The influencing factors considered in the orthogonal mechanical tests were the proportion of aggregate and binder, the proportion of polystyrene foam in the entire model, the proportion of binder and regulator, and the size of polystyrene foam. Five levels were set for each factor, and mechanical parameters such as compressive strength, tensile strength, elastic modulus, axial strain, and Poisson’s ratio were tested for each group of samples. The changes in mechanical parameters with the levels of the above four factors were studied. The study found that modifying the proportion of aggregate to binder can alter the elastic modulus, tensile strength, and compressive strength values of sandstone-like material. The size of polystyrene foam can be modified to alter the axial strain values of sandstone-like materials. Additionally, adjusting the ratio of binder and regulator can modify the value of Poisson’s ratio. The comparison of mechanical parameters between sandstone-like samples and sandstone reveals that sandstone-like materials can better simulate the deformation and failure mechanisms of sandstone. The error in the main mechanical parameters, such as modulus of elasticity, strength, and Poisson’s ratio, is less than 7%, indicating a greater resemblance between sandstone-like materials and sandstone. Therefore, sandstone-like materials can be used to investigate the deformation law, damage evolution law, and failure mechanism of sandstone. This can help alleviate the difficulty of obtaining specimens of deep damaged rock and the high cost of testing.

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Numerical Simulation of Rock Mass Structure Effect on Tunnel Smooth Blasting Quality: A Case Study

Cited by 6 publications

References 30 publications

Experimental and Numerical Study on the Effect of Three-Hole Simultaneous Blasting Technology on Open-Pit Mine Bench Blasting

Experimental and Numerical Study on the Effect of Three-Hole Simultaneous Blasting Technology on Open-Pit Mine Bench Blasting

Calculation of hole spacing and surrounding rock damage analysis under the action of in situ stress and joints

Investigation of Sandstone-like Material for Damaged Rock Mass Based on Orthogonal Experimental Method

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