Numerical analysis of rock fracturing by gas pressure using the extended finite element method

Abstract

High energy gas fracturing is a simple approach of applying high pressure gas to stimulate wells by generating several radial cracks without creating any other damages to the wells. In this paper, a numerical algorithm is proposed to quantitatively simulate propagation of these fractures around a pressurized hole as a quasi-static phenomenon. The gas flow through the cracks is assumed as a one-dimensional transient flow, governed by equations of conservation of mass and momentum. The fractured medium is modeled with the extended finite element method, and the stress intensity factor is calculated by the simple, though sufficiently accurate, displacement extrapolation method. To evaluate the proposed algorithm, two field tests are simulated and the unknown parameters are determined through calibration. Sensitivity analyses are performed on the main effective parameters. Considering that the level of uncertainty is very high in these types of engineering problems, the results show a good agreement with the experimental data. They are also consistent with the theory that the final crack length is mainly determined by the gas pressure rather than the initial crack length produced by the stress waves.

Experimental Study on High‐Pressure Air Blasting Fracture for Coal and Rock Mass

“…e two main stages of stress wave and high-pressure gas action during blasting are identified in the process of rock fracture caused by explosive blasting, which are helpful to crack propagation and rock breakage. e effect of stress wave is to produce initial crack, and high-pressure gas will lead to crack propagation [7][8][9]. e blasting mechanism of explosive and high-pressure gas is mainly different from the peak pressure and duration of stress wave [10].…”

Optimization of ring blasting in sublevel stoping gold mine

“…Also, excessive damage of surrounding rock mass leads to frequent instabilities. Blast fragmentation has been widely investigated and some of notable research results are presented by Goodarzi et al (2015), Esen et al (2003), Cho and Kaneko (2004) and Lapcevic (2014b, 2016a). Excessive damage to surrounding rock mass is also one of the huge problems that occurs in underground mining since it impact the stability of the openings and stopes.…”

Application of Confined Blasting in Water-Filled Deep Holes to Control Strong Rock Pressure in Hard Rock Mines

“…Meanwhile, the presence of water can help guide the explosive shock waves, promote fracture propagation, avoid high temperature, and prevent hazards like sparks. In this technique, the blast-hole loading and sealing procedure is simplified and the explosive in blast holes can presplit hard coal and rock in a safer and more effective manner [22][23][24][25]. In this study, the technique of confined blasting in water-filled deep holes was applied to presplit the thick seam and hard roof in Datong Coal Mine area.…”