Excavation Method of Reducing Blasting Vibration in Complicated Geological Conditions

In situ stress has a large influence on blasts in deep mines and should be considered in blasting design. In this study, explosion crater tests were conducted to investigate the variation of specific charges under different stress loading conditions. It was revealed that rock blasting under high stress is different from that under low stress. A correction coefficient for specific charge was defined to consider the influence of in situ stress on blasting. A quantitative relation between the correction coefficient, stress-to-strength ratio, and lateral stress coefficient was presented. Based on the explosion-crater test results, a design method for specific charges was proposed with the consideration of in situ stress. Finally, the design method was applied to a field blasting test at Hongtoushan Copper Mine. The test results indicate that the proposed design method can effectively use the high in situ stress at depth for rock fragmentation. Compared with the original blasting design, the specific charge is reduced by 19.8% and the average block rate is reduced from 6.8% to 2.84%. At the same time, the blasting boundary is well controlled and the ore loss and dilution rates are reduced. This research has important guiding significance to deep mine blasting design.

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“…e correction coefficient corresponding to λ � 0 and λ � 1 can be calculated using equation (7), and the result is shown in Figure 7.…”

Section: Correction Coefficient For Specific Chargementioning

confidence: 99%

“…e drill-and-blast method is one of the main methods of rock fragmentation [6][7][8][9]. When the drill-and-blast excavation method is used in excavation of deep mineral resources, rocks are fragmented under the coupled effect of high static stress and blastinginduced dynamic stress [8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Design Method for Specific Charge in Deep Mining considering Influence of In Situ Stress

Zhang

Hao

Wang

et al. 2021

Advances in Civil Engineering

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“…According to equation (16), adopting steel fiber concrete can improve the bond characteristic of the interface (σ 24hb ) and thus increases the safety distance of shotcrete. (2) Operation sequences in tunnel excavation can be ordered to reduce blast charge and therefore significantly controls blast vibration [21,44]. A certain distance should be kept between upper and lower benches to keep the shotcrete from being repeatedly disturbed by blasting in a short time.…”

Section: Recommendations For the Security Of Shotcretementioning

confidence: 99%

“…In general, the safety of shotcrete subjected to blast vibration is affected by blast parameters, geological characteristics, and distance between blast and observation points [21]. It can also be determined by the failure criteria of shotcrete.…”

Section: Introductionmentioning

confidence: 99%

Safety Distance of Shotcrete Subjected to Blasting Vibration in Large‐Span High‐Speed Railway Tunnels

Zhang

Fang

et al. 2019

Shock and Vibration

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e drill and blast method is widely used in constructing tunnels in rock. Unfortunately, blasting vibration can damage newly performed shotcrete layers which are major support structures to stabilize surrounding structures. erefore, investigation of the influence of blasting on shotcrete and determining reasonable distance between blasting work face and shotcrete position is of great importance. In this paper, a large-span tunnel excavated by drill and blast method acting as a high-speed railway station has been investigated. Blast vibration in the tunnel was recorded using microseismic monitoring technique. Empirical prediction equations for peak particle velocity (PPV) were obtained through regression analysis based on the obtained monitoring data. e attenuation law of tensile stress imposed on shotcrete layer due to blasting and bond strength of shotcrete-rock interface was also investigated. Minimum safety distance between shotcrete and blasting positions was calculated based on bond failure criterion. Evolution law considering different factors including blasting charge, rock mass class, and setting time of shotcrete was also obtained, which could be applied to determine blast charge shotcrete arrangements for tunnel constructions in future. e obtained results showed that the safety of shotcrete could be ensured and shotcrete falling off the rock could be prevented under current blast constructions.

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“…Li and Li [20] used the finite element method to compare and analyze the CD method, the step method, and the reserved core soil in the blasting excavation method and determined the damping excavation method for shallow buried tunnels crossing dense residential areas. Xie et al [21] used LS-DYNA software to simulate six different types of blasting excavation methods. By analyzing them, a reasonable blasting excavation method was proposed to reduce blasting vibration.…”

Section: Introductionmentioning

confidence: 99%

Optimization Analysis of Controlled Blasting for Passing through Houses at Close Range in Super‐Large Section Tunnels

Song

Mao

Tian

et al. 2019

Shock and Vibration

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According to the on-site vibration velocity monitoring and peak vibration velocity prediction, it is found that the maximum vibration velocity generated by the existing Dizong blasting scheme does not meet the requirements of the maximum allowable vibration velocity of houses. Therefore, the existing blasting scheme is optimized by reducing the maximum single-segment charge and a variety of damping measures such as multistage duplex wedge groove, adding damping hole, and millisecond blasting. In addition, the blasting data before and after optimization are analyzed and compared by wavelet (packet) technology. The results show that the optimized blasting main frequency domain is increased to 50∼150 Hz and the maximum vibration intensity value is reduced by 79.8%. Based on the time-energy analysis, the maximum energy value is reduced by 67.75% compared with the original scheme, and the dominant energy of the original scheme is reduced by 97.81%, 71.49%, 82.44%, 95.93%, and 93.03%, respectively, after optimization. The maximum vibration velocity generated by the optimized blasting scheme construction is 1.12 cm/s, which is less than the maximum allowable vibration velocity of the building of 1.2 cm/s, which meets the maximum allowable vibration velocity requirements of the building. The optimized blasting scheme realizes the safe and rapid construction of the two steps of the Dizong tunnel, which can provide a reference for similar engineering construction in the future.

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Excavation Method of Reducing Blasting Vibration in Complicated Geological Conditions

Cited by 10 publications

References 29 publications

Design Method for Specific Charge in Deep Mining considering Influence of In Situ Stress

Design Method for Specific Charge in Deep Mining considering Influence of In Situ Stress

Safety Distance of Shotcrete Subjected to Blasting Vibration in Large‐Span High‐Speed Railway Tunnels

Optimization Analysis of Controlled Blasting for Passing through Houses at Close Range in Super‐Large Section Tunnels

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