scholarly journals Experimental Study on Explosion Pressure and Rock Breaking Characteristics under Liquid Carbon Dioxide Blasting

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Yanan Zhang ◽  
Junren Deng ◽  
Bo Ke ◽  
Hongwei Deng ◽  
Jielin Li

A liquid carbon dioxide blasting experiment was carried out under free field conditions, alongside a liquid carbon dioxide rock breaking experiment, to investigate explosion pressure variation and rock breaking characteristics under liquid carbon dioxide blasting. The experimental results show that the internal and external explosion pressures of the liquid carbon dioxide fracturing devices all rapidly increased at first, before attenuating vibrantly after blasting. When the explosion pressure was raised, the internal explosion pressure increased first exponentially and then linearly, while the external explosion pressure increased exponentially throughout. The duration time of the blasting effect stage was about 45 ms. Under the combined effect of jet impingement and a gas wedge of high-pressure carbon dioxide, the rock is subjected to tensile failure. The impact failure and the “gas wedge effect” of high-pressure carbon dioxide play a key role in the rock breaking of liquid carbon dioxide blasting technology.

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4134
Author(s):  
Bo Ke ◽  
Keping Zhou ◽  
Gaofeng Ren ◽  
Ji Shi ◽  
Yanan Zhang

As environmental requirements become more stringent, the liquid carbon dioxide blasting system is one of the non-explosive blasting technologies that, with low tensile stress energy, will replace the chemical explosive blasting technology, and the impact pressure characteristic of high-pressure fluid is a crucial factor in the process of rock breaking. To further investigate the impact and pressure attenuation characteristics of high-pressure fluid during the phase transition of liquid carbon dioxide blasting system, the pressure curves of high-pressure fluid in liquid carbon dioxide blasting systems at different distances were measured in the laboratory. Based on the mechanism analysis of phase transition kinetics, the initial jet velocity of the four experiments was calculated, and the rationality of results was verified by the Bernoulli equation. The general expression of the positive phase pressure–time function was proposed, and the idealized impact pressure curve can be divided into five stages. The impact pressure field of the liquid carbon dioxide blasting system can be divided into three areas at different distances: the explosive jet impact zone, the jet edge zone and the shock wave action zone, and the pressure–contrast distance fitting equation of the liquid carbon dioxide blasting system were obtained.


Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2909 ◽  
Author(s):  
Feng Gao ◽  
Leihu Tang ◽  
Keping Zhou ◽  
Yanan Zhang ◽  
Bo Ke

The technique of breaking rocks using carbon dioxide phase transition technology is being widely applied in current research. This article combines theoretical and practical methods to analyze the mechanism by which high-pressure gas breaks rock at different stages. Using the observation that liquid carbon dioxide forms a high-pressure jet from release holes at the moment of release, a formula for calculating the initial pressure on the wall in the direction of release was obtained, and the pattern of initial crack formation on the borehole wall under different initial stress conditions was examined. An experiment using carbon dioxide phase transition technology to fracture rock without an initial stress field was conducted. The mechanism of generation and expansion of subsequent cracks under stress waves and high-pressure gas was analyzed, and the formula for calculating crack propagation radius under stress waves was obtained. The results suggested that under the quasi-static action of high-pressure gas, cracks begin to develop when the stress intensity factor KI at the crack tip is equal to or greater than the fracture toughness KIC of the rock.


2012 ◽  
Vol 72 ◽  
pp. 213-222 ◽  
Author(s):  
Meysam Davoody ◽  
Gholamreza Zahedi ◽  
Mazda Biglari ◽  
M.A.A. Meireles ◽  
Alireza Bahadori

2003 ◽  
Vol 2003.3 (0) ◽  
pp. 309-310
Author(s):  
Yasuharu NAKAJIMA ◽  
Hideyuki SHIROTA ◽  
Ryuji KOJIMA ◽  
Kenji YAMANE ◽  
Izuo AYA ◽  
...  

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