Key Blasting Parameters for Deep‐Hole Excavation in an Underground Tunnel of Phosphorite Mine

Chai, Xiuwei; Shi, Sha-sha; Yan, Yao-feng; Li, Jianguo; Zhang, Long

doi:10.1155/2019/4924382

Cited by 10 publications

(11 citation statements)

References 11 publications

(9 reference statements)

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“…In addition, since the straight hole cutting blasting technique with a central empty hole is currently the most commonly used straight hole cutting method, charging and supplemental blasting were carried out at the bottom of the central empty hole in this study. With the change of construction conditions, the holes used for cutting blasting might not follow this traditional arrangement form in some actual projects, but the empty holes used to provide additional free face and compensation space were usually still maintained (Chai et al 2019;Chandrakar et al 2021). At this time, according to the blasting concept proposed in this study, charging and supplemental blasting could also be conducted at the bottom of empty holes to improve the deep hole cutting effect, but the specific charge parameters and initiation network need to be designed according to the actual conditions.…”

Section: Discussionmentioning

confidence: 99%

“…Zuo et al (2018) performed model tests to explore the specific influence of empty hole diameter on straight hole cutting blasting, and the testing results indicated that the cutting cavity depth gradually increased with increasing diameter of the empty hole. Chai et al (2019) supposed that the number of empty holes had an appreciable impact on the cutting results and proved that the increasing quantity of empty holes was positive for straight hole cutting blasting. In addition, Chandrakar et al (2021) proposed a new concept of the void ratio and investigated its impact on the cutting effect according to the field testing results and concluded that a high void ratio was more effective in achieving a satisfactory cutting effect.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Study on the novel technique of straight hole cutting blasting with a bottom charged central hole exploded supplementally

Cheng

Wang

et al. 2021

Arab J Geosci

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To improve the cutting efficiency in the deep hole blasting of rock roadways, a straight hole cutting blasting technique with supplemental blasting of the central hole was developed. First, the blasting mechanisms of the traditional and novel cutting methods were analysed theoretically. For the novel cutting method, the upper uncharged part of the central hole still acted as empty hole. Cutting hole blasting could eject most of the rock mass in the cutting cavity and hence produce a new free face to weaken the clamping effect of central hole blasting. Then, the residual rock mass could be fully removed after central hole blasting. Second, simulation of the new cutting mode was conducted, which visualized the stress wave forming process. Simulation results showed that the rock mass at the bottom of the cutting cavity could be predamaged by the stress wave caused by cutting hole blasting, and the high-intensity stress field generated by central hole blasting would lead to further damage to the residual rock mass. Thus, the residual rock mass could be thrown out readily. Finally, the auxiliary roadway of an iron mine was selected for the blasting experiments. After statistical analysis, due to the supplemental blasting of the central hole, the average blasting footage was increased by 0.35 m, and the average specific charge was reduced by 0.43 kg•m −3 , which validated the predominance of the novel cutting method in the deep hole blasting of rock roadways.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on the novel technique of straight hole cutting blasting with a bottom charged central hole exploded supplementally

Cheng

Wang

et al. 2021

Arab J Geosci

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“…To improve the excavation efficiency, Ma et al obtained the critical distance of the borehole restraint by field test and they proposed a new charging structure without detonating cord and achieved a good smooth blasting effect [8]. Chai et al studied the effect of the arrangement of cut holes on the control blasting effect and they found that the layout of four empty holes could improve the utilization rate of explosive better than the two, indicating that reasonable reserved compensation space could improve the blasting effect and tunneling efficiency [9]. Duan et al investigated the influence of blasting excavation on existing tunnels under small spacing [10].…”

Section: Introductionmentioning

confidence: 99%

Controlling Vibration Speed in Tunnel Excavation Using Fine Blasting Method under Complex Environmental Conditions

Zhang

Wang

et al. 2021

Shock and Vibration

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It is very important to reduce the impact of blasting vibration on the surrounding structures during the tunnel drilling-blasting excavation. Taking the diversion tunnel of the urban water supply project in Zhumadian, Henan Province, China, as an example, the segmentation linear function between the drilling rig and borehole depth was established by fining blasting design. The test of the blasting number and particle vibration velocity was designed. The propagation and attenuation characteristics of blast vibration velocity in the surrounding rocks of the tunnel were analyzed by using theoretical calculation and field monitoring methods. Results show that the fine blasting design can realize the superposition of negative phase of shock waveform to reduce the vibration speed. With the increase of the blasting number, the attenuation of the particle vibration velocity shows a negative exponential function, and the dimensionless vibration velocity loss increases in a power function. The greater the loss, the greater the energy loss during the shock wave propagation process, which is more conducive to ensuring the stability of the protected buildings. The research results can provide the reference for similar engineering practices.

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“…ese factors cause certain restraints against efficiency of construction and the engineering quality of the tunnel. erefore, studying the influences of posterior tunnel construction on the stability of the anterior tunnel in the transition section of branching-out tunnel has important practical significance [9,10].…”

Section: Introductionmentioning

confidence: 99%

Blasting‐Induced Vibration Response of the Transition Section in a Branching‐Out Tunnel and Vibration Control Measures

Cao

Zhang

Ling

2020

Advances in Civil Engineering

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Blasting-induced vibration during the excavation of transition section in a branching-out tunnel causes damage and hence affects the safety and stability of the supporting structure and surrounding rock. To examine the effects of excavation and blasting of the transition section in the posterior tunnel on the supporting structures of the anterior tunnel, the influences of the blasting-induced vibration in the posterior tunnel on the anterior tunnel were analyzed under different surrounding rock levels, excavation techniques, distances from explosive source, and net spans. This method was performed by combining numerical simulation with blasting-induced vibration monitoring according to the construction characteristics of the transition section in a branching-out tunnel of a highway. A control technique was investigated to assure the safety and stability of the anterior tunnel during the excavation and blasting of the posterior tunnel. Results demonstrate that (1) the vibration velocity peak behind the blasting excavation surface of the tunnel is higher than that in front. These results suggest paying much attention in monitoring vibration velocity within 10 m behind the excavation surface. (2) The blasting-induced vibration velocity peak on the spandrel at the side that faces the blasting in the anterior tunnel is 2.0–2.5 times than that at the side behind the blasting. Moreover, the blasting-induced vibration velocity peak on the haunch at the side that faces the blasting in the anterior tunnel is 6-7 times than that at the side behind the blasting. (3) Instead of the full-face excavation method, the use of center cross diagram (CRD) technique or side wall pilot tunnel method is suggested for the excavation of surrounding rocks of IV-level, V-level, and III-level with a net span smaller than 3 m. (4) Vibration control measures, such as double wedge-shaped cut blasting and floor blast-hole staged detonation, were adopted by designing and optimizing blasting parameters (e.g., total explosives, maximal segment explosive quantity, detonation order, and detonation interval) in posterior tunnel. According to the test, the blasting-induced vibration velocity peak, which is monitored in the anterior tunnel, can be controlled within 10 cm/s to assure the safety and stability of the supporting structure and surrounding rocks of the tunnel.

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Key Blasting Parameters for Deep‐Hole Excavation in an Underground Tunnel of Phosphorite Mine

Cited by 10 publications

References 11 publications

Study on the novel technique of straight hole cutting blasting with a bottom charged central hole exploded supplementally

Study on the novel technique of straight hole cutting blasting with a bottom charged central hole exploded supplementally

Controlling Vibration Speed in Tunnel Excavation Using Fine Blasting Method under Complex Environmental Conditions

Blasting‐Induced Vibration Response of the Transition Section in a Branching‐Out Tunnel and Vibration Control Measures

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