A Preliminary Study on the Design Method for Large‐Diameter Deep‐Hole Presplit Blasting and Its Vibration‐Isolation Effect

Xiao, Shuangjiu; Wang, Hongsheng; Dong, Guowei

doi:10.1155/2019/2038578

Cited by 8 publications

(5 citation statements)

References 21 publications

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“…Based on the indepth research, the theoretical model of damage mechanics has become one of the main research directions. Based on isobaric conditions, this paper establishes a mechanical model of the surrounding rock with an excavation radius of R 0 without a supporting structure by analyzing the displacement of the surrounding rock mass and blasting vibration [23][24][25], as shown in Figure 2.…”

Section: E Analytical Solution Of Radial Displacement Based On Cumulative Effect Of Particle Velocitymentioning

confidence: 99%

Study on the Vibration Effect of Short Footage Blasting Load on Surrounding Rock-Support Structure of Tunnel

Dai

Sui

2020

Shock and Vibration

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In the excavation process of a drilling and blasting tunnel, it takes multiple blasting excavations to form, so it is inevitable to produce multiple blasting impact loads, which will cause certain vibration damage to the surrounding rock-support structure. To solve this problem, based on the attenuation formula of blasting vibration wave and considering the cumulative effect of short footage blasting load, the radial displacement formula of surrounding rock particles is derived, and the analytical solution of vibration velocity field is obtained by using the method of separating variables. Then, taking Cuobuling station of Qingdao Metro as the engineering background, the finite element software is used to simulate the tunnel excavation process under the action of short footage multiple blasting. The vibration damage impact of multiple blasting loads on the surrounding rock-supporting structure is analyzed from the accumulated displacement value and vibration velocity cumulative value of the excavation tunnel. The results show that the damage accumulation effect is produced in the surrounding rock of each section during the blasting construction, among which the accumulation is the largest at the arch bottom. With the increase of blasting times, the damage of the surrounding rock is still accumulating gradually. Compared with the first blasting, the peak value of vibration velocity of the second blasting increased by 114%, and with the increase of blasting times, the variation trend of maximum vibration velocity of the measuring point showed an upward trend, but the subsequent vibration acceleration decreased. Under the condition of grade V surrounding rock, when the thickness of the concrete spray layer is 350 mm, the maximum displacement cumulative value of each measuring point in profile 1-1 is reduced by about 50.4% compared with that without support. According to the displacement nephogram of the concrete spray layer, the displacement of the concrete spray layer accumulates after three times of blasting, which affects the stability of the supporting structure. Finally, an example analysis is carried out and compared with the analytical model results to verify the accuracy of the mechanical model.

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Section: E Analytical Solution Of Radial Displacement Based On Cumulative Effect Of Particle Velocitymentioning

confidence: 99%

Study on the Vibration Effect of Short Footage Blasting Load on Surrounding Rock-Support Structure of Tunnel

Dai

Sui

2020

Shock and Vibration

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“…At the interface of the smashed zone, the shock wave attenuates to a stress wave and the wave velocity attenuates to the elastic longitudinal wave velocity in rock mass, where the peak pressure is where u r is the motion velocity of rock particles at the interface of smashed zone, m/s; a ′ and b ′ are rock-related constants determined by experiment. On the other hand, according to the attenuation relationship between the peak pressure of shock wave and distance, the peak pressure of shock wave at the interface of smashed zone can be expressed as follows [41]:…”

Section: Hole Spacing Optimisationmentioning

confidence: 99%

Blast-Casting Mechanism and Parameter Optimization of a Benched Deep-Hole in an Opencast Coal Mine

Lai

Zhang

et al. 2020

Shock and Vibration

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During the research on bench deep-hole blast casting, the blast-casting parameters are directly related to the blast-casting results, so it could reveal the mechanism for improving the effect thereof. Based on the principle of the plane charge method, both the stress wave and detonation gas were considered to affect rock fragmentation and casting, a model of overburden fragmentation and casting process around the blasting hole was established, and bench deep-hole blast-casting behaviours were elucidated. By using the Factor Analysis Method (FAM), a correlation analysis model of factors influencing blast-casting results was built. The results proved that powder factor (or specific charge) ranked first in terms of its influence, followed by hole spacing, minimum resistance line, burden, and bench height. The formulae for calculating the limit powder factor value and the spacing of blasting holes were derived for different rock properties. The results showed that the optimum hole spacing was no more than 12.49 m and the powder factor was no more than 0.75 kg/m3, and it proved that an effective casting percentage (ECP) of 34% could be realized.

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“…The integrity and physical mechanics of the rock mass in the damaged excavation zone deteriorate at various degrees [4], and have direct impact on the quality of the foundation construction, the economic benefits of the project, and the overall construction progress. Therefore, controlling excavation damage and reducing blasting influence on the rock-foundation protection layer is a focus of engineering-practice and rock-dynamics research [5].…”

Section: Research Backgroundmentioning

confidence: 99%

Piezoceramic-Based Damage Monitoring of Concrete Structure for Underwater Blasting

Zhong

Xiong

2020

Sensors

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This paper developed a piezoelectric-transducer-based damage detection of concrete materials after blasting. Two specimens (with or without an energy-relieving structure) were subjected to a 40 m deep-underwater blasting load in an underwater-explosion vessel, and their damage was detected by a multifunctional piezoelectric-signal-monitoring and -analysis system before and after the explosion. Statistical-data analysis of the piezoelectric signals revealed four zones: crushing, fracture, damage, and safe zones. The signal energy was analyzed and calculated by wavelet-packet analysis, and the blasting-damage index was obtained after the concrete specimen was subjected to the impact load of the underwater explosion. The damage of the two specimens gradually decreased from the blast hole to the bottom of the specimen. The damage index of the specimen with the energy-relieving structure differed for the fracture area and the damage area, and the damage protection of the energy-relieving structure was prominent at the bottom of the specimen. The piezoelectric-transducer-based damage monitoring of concrete materials is sensitive to underwater blasting, and with wavelet-packet-energy analysis, it can be used for postblasting damage detection and the evaluation of concrete materials.

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A Preliminary Study on the Design Method for Large‐Diameter Deep‐Hole Presplit Blasting and Its Vibration‐Isolation Effect

Cited by 8 publications

References 21 publications

Study on the Vibration Effect of Short Footage Blasting Load on Surrounding Rock-Support Structure of Tunnel

Study on the Vibration Effect of Short Footage Blasting Load on Surrounding Rock-Support Structure of Tunnel

Blast-Casting Mechanism and Parameter Optimization of a Benched Deep-Hole in an Opencast Coal Mine

Piezoceramic-Based Damage Monitoring of Concrete Structure for Underwater Blasting

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