The free surface influence on blast vibration

Blair, D. P.

doi:10.1016/j.ijrmms.2015.04.006

Cited by 54 publications

(27 citation statements)

References 10 publications

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“…Blair [43,44] noted that grid size has an important effect on calculation accuracy and time consumption. In this simulation, due to the limitation of computer capacity, small grids were used near the cut holes and at the bottom of the cut cavity to ensure precision, while large grids were adopted farther from the cut holes to reduce computational complexity and improve efficiency.…”

Section: Numerical Modelmentioning

confidence: 99%

A Study on Cut Blasting with Large Diameter Charges in Hard Rock Roadways

Cheng

Wang

et al. 2020

Advances in Civil Engineering

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To overcome the problems of poor cutting effects in hard rock roadways, a cut blasting technique with large diameter charges was developed; that is, the cut holes employ 50 mm diameter blast holes and 45 mm diameter explosive sticks, while the other holes adopt 42 mm diameter blast holes and 35 mm diameter explosive sticks. First, the effect of charge diameter on damage range and cut cavity formation was analyzed. Next, simulation of wedge cut for different charge diameters was conducted to reveal the stress wave developments and compare the stress field intensities. Finally, field tests were conducted to verify the viability of this technique. The results indicate that large diameter charges can increase the damage range around cut holes to improve the fragmentation degree of the rock mass in the cut cavity and significantly enhance the cavity formation power to better expel the rock mass fragments. The stress wave evolution of wedge cut was visualized using numerical simulations, which confirmed that the use of large diameter charges in cut holes increases the stress field intensity in the cut cavity and hence increases the damage degree of the rock mass. In this study, the use of a large diameter charge for cut blasting increased the average footage by 0.30 m, and the average utilization rate of blast holes increased by 12.5%. Therefore, the cutting effects in hard rock roadways can be improved by using large diameter charges, which increase the blasting footage and the utilization rate of blast holes.

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Section: Numerical Modelmentioning

confidence: 99%

A Study on Cut Blasting with Large Diameter Charges in Hard Rock Roadways

Cheng

Wang

et al. 2020

Advances in Civil Engineering

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“…The millisecond delay electric detonator is used for underground coal mine, its delay time interval between segments is 20 ms and the total delay time is less than 130ms. With the increase of roadway section, detonator segments are not enough in construction or overmuch blast hole in a segment detonation are appeared gradually, which indicated that the in-site requirements are not meet by the existing regulation for delay time [18,19]. By changing delay time interval between segments and the total delay time remain the same, our group conducting a testing on large section of soft rock roadway, and throwing distance of gangue reduced from 20 m-25 m before test to 10 m-15 m during the test.…”

Section: Priming Technology In Millisecond Delaymentioning

confidence: 99%

Blasting vibration on deep shaft ingate rock damage and its control measures

Xue¹,

Yao²,

Cheng³

et al. 2016

J. vibroeng.

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Traditional control of ingate surrounding rock is partial to repair and optimization after failure of supporting structure, and only for specific structure of ingate is studied, without considering blasting vibration effect on damage of ingate surrounding rock, and lack of study on layout design of ingate surrounding chamber group. Based on the research status of deep vertical shaft ingate, this paper has carried on theoretical analysis and field testing for ingate surrounding rock damage affected by vibration load produced in process of excavation and blasting in mine roadway and chamber, getting the change law of ingate surrounding rock damage under blasting vibration, and new control measures about loaded constitution, delay blasting technology, set isolation hole, especially the rational layout of ingate surrounding chamber group are provided, combined with numerical simulation software to determine reasonable spacing of ingate surrounding chamber group in deep vertical shaft, and optimize construction sequence. Finally, research achievements are applied to engineering practice, the results of field deformation monitoring show that ingate in mine roadway and chamber can maintain good integrity under construction process.

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“…However, in the process of numerical simulation, the large deformation and distortion of the finite elements at high pressure often cause the calculation process to be terminated when using JWL EOS. In order to overcome this problem, fluid-solid coupling method and the method of applying pressure delay function are usually used [30][31][32][33][34][35][36]. The fluidsolid coupling method needs to refine the element grid of rock mass near the boreholes, since more unit grids are required in the numerical calculation of large-scale blasting engineering, which raises the numerical calculation difficulty.…”

Section: Introductionmentioning

confidence: 99%

Excavation Method of Reducing Blasting Vibration in Complicated Geological Conditions

Xie

Jin-cai

et al. 2018

Shock and Vibration

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Drilling and blasting method as a common excavation method is widely used in the underground engineering construction. However, in the complicated geological conditions, the path of blasting excavation available has limitation, and then the larger blasting vibration is produced, which influence the stability and safety of the protected structure. To effectively reduce the blasting vibration by optimizing the blasting excavation method, firstly, the site test on blasting vibration is conducted to obtain the blasting vibration data; secondly, the LS-DYNA software is applied to simulate the vibration generated by blasting in site test, based on back analysis on the blasting vibration, the mechanical parameters of the rock mass are obtained, and they are used to simulate six different types of blasting excavation method. According to the analysis on them, the reasonable blasting excavation method is proposed to reduce the blasting vibration which can satisfy the blasting safety regulation.

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The free surface influence on blast vibration

Cited by 54 publications

References 10 publications

A Study on Cut Blasting with Large Diameter Charges in Hard Rock Roadways

A Study on Cut Blasting with Large Diameter Charges in Hard Rock Roadways

Blasting vibration on deep shaft ingate rock damage and its control measures

Excavation Method of Reducing Blasting Vibration in Complicated Geological Conditions

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