Numerical simulation and experiment analysis of improving permeability by deep-hole presplitting explosion in high gassy and low permeability coal seam

Feng, Cai; Liu, Zegong; Lin, Baiquan; Li, Wei

doi:10.1007/s12404-009-0213-7

Cited by 15 publications

(12 citation statements)

References 3 publications

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“…These fractures extend over a large range during the action of the blasting stress wave and the blasting gas wedge. With continuous research on the formation mechanism of coal fractures in the effect of blasting, many theories have been developed and numerous discoveries made, such as stress wave theory and blasting gas quasistatic compression failure theory (Yang et al 1991), fracturing extension under the action of dynamic compression impact and stress superposition combining blasting gas (Cai et al 2007), and dynamic and static compression failure theory (Li et al 2009). Unlike conventional blasting, the penetration effect of the jet flow generated by cumulative blasting plays an important role in directional fracturing.…”

Section: Studies On the Penetrating Effect Of Cumulative Blastingmentioning

confidence: 99%

Research progress on permeability improvement mechanisms and technologies of coalbed deep-hole cumulative blasting

Guo

Zhao

et al. 2020

Int J Coal Sci Technol

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Coalbed gas extraction is an important means of exploiting and utilizing gas resources, as well as a means of preventing coal mine disasters. In view of the low gas extraction rate from coalbeds with high gas content and low permeability, a method of improving permeability through deep-hole cumulative blasting is applied to develop initial directional fractures using a jet flow. Under the action of the blasting stress wave and detonation gas wedge, the fractures extend over a large range within the coal, thereby improving coalbed permeability. This study focuses on the criteria of cumulative blasting-induced coalbed fracturing based on a literature review of the penetration effect of cumulative blasting. On this basis, we summarize the coal fracturing zone, crack extension process, and the key technologies of charging and hole sealing for cumulative blasting. In addition, the latest research progress in the optimization of field test drilling and blasting parameters for cumulative blasting is introduced. Research findings indicate that the permeability improvement mechanism of cumulative blasting could be further enhanced, and the technology and technical equipment are in urgent need of improvement. Finally, development trends in the cumulative blasting permeability improvement technique are identified.

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Section: Studies On the Penetrating Effect Of Cumulative Blastingmentioning

confidence: 99%

Research progress on permeability improvement mechanisms and technologies of coalbed deep-hole cumulative blasting

Guo

Zhao

et al. 2020

Int J Coal Sci Technol

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“…The fissure continues to extend (the boundary of the crack zone) until the burst-gas pressure decreases below the geo-stress and coal strength. It is generally accepted that the boundary of the crack zone is the effective cracking range of the blasting [27]. Thus the drainage hole can be employed in this range, and the free surface can be effectively provided.…”

Section: Division Of Blasting Influencementioning

confidence: 99%

Optimization of Drilling Layouts Based on Controlled Presplitting Blasting through Strata for Gas Drainage in Coal Roadway Strips

et al. 2017

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Abstract:The controlled presplitting blasting technique is widely used in mining engineering to improve the permeability and gas extraction efficiency of coal seams. One of the key factors is the appropriate arrangement of the blasting and drainage holes, which can help improve the gas drainage quantity. To optimize the drilling layout to enhance gas-drainage efficiency, a series of controlled presplitting blasting tests were conducted at the Pingdingshan No. 8 coal mine. Based on the analysis of variations in stress and longitudinal-wave velocity of the coal in different blasting ranges, the results show that the stress on the coal at a distance of 1 m from the blasting hole decreased significantly after blasting; thus, the coal exhibited negligible bearing capacity and the longitudinal-wave velocity decreased by 56%. However, the coal exhibited particular bearing capacity at a distance of 3 m away from the blasting hole, and the longitudinal-wave velocity decreased by 35%. The stress and longitudinal-wave velocity at a distance of 5 m from the blasting hole were unaffected by the blasting. The blasting integrity rate of coal k v was defined to characterize the effect of blasting on the coal-seam fracture. The effective cracking and effective influence radii of blasting under these working conditions were predicted to be in the ranges 3.3-3.4 m and 7.2-7.3 m, respectively. According to the test results, the borehole layout was optimized in the field testes for gas drainage in coal roadway strips, and the amounts of pure gas extracted after blasting were thus increased by 1.54-2.24 times the amount before blasting.

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“…Based on the Holmquist-Johnson-Cook model, Hu et al built a dynamic damage model of presplit blasting and studied the evolution and formation process of the presplit cracks using numerical simulation [12]. rough numerical simulation, Cai et al reproduced the shattering induced by dynamic impact, propagation, and superposition of stress waves and crack growth driven by blasting gas in a deep-hole presplit blasting process [13,14]. Wang et al analysed the mechanism underpinning presplit blasting and applied it to control the caving of underground roadway roofs [15].…”

Section: Introductionmentioning

confidence: 99%

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

Xiao

Wang

Dong

2019

Shock and Vibration

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Presplit blasting can reduce vibration and back impact induced by cast blasting, thus resulting in a smooth bench slope. To design reasonable presplit blasting parameters, this research investigated the formation of presplit faces based on the explosion mechanics and revealed the cracking mechanism of presplit blasting. According to the stress distribution in the vicinity of the blast holes under the action of explosive stress waves and blasting gas, we deduced theoretical formulae for parameters including charge mass in blast holes, hole spacing, and distance from presplit blast holes to cushion holes. On this basis, a method was proposed for the design of large-diameter deep-hole presplit blasting. Field testing was conducted by setting different spacing for presplit blast holes, to monitor the blasting-induced vibration. The results showed that appropriate hole spacing can reduce the particle vibration velocity and the attenuation index of blasting-induced vibration changed slightly while the attenuation coefficient decreased significantly; the formed presplit faces were smooth and had a high half-cast factor. Finally, the reasonable hole spacing for presplit blasting, distance from presplit blast hole to the cushion hole, and the charge mass in blast holes in the Heidaigou open-pit coal mine were determined, respectively.

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Numerical simulation and experiment analysis of improving permeability by deep-hole presplitting explosion in high gassy and low permeability coal seam

Cited by 15 publications

References 3 publications

Research progress on permeability improvement mechanisms and technologies of coalbed deep-hole cumulative blasting

Research progress on permeability improvement mechanisms and technologies of coalbed deep-hole cumulative blasting

Optimization of Drilling Layouts Based on Controlled Presplitting Blasting through Strata for Gas Drainage in Coal Roadway Strips

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

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