Effect of an eccentric decoupled charge on rock mass blasting

Jung-Gyu Kim, Department of Energy and Resources Engineering, Chonnam National University, Korea
Mahrous A. M. Ali, Mining and Petroleum Engineering Department, Faculty of Enigneering, Al-Azhar University, Qena, Egypt
Jong-Gwan Kim, Department of Energy and Resources Engineering, Chonnam National University, KoreaFollow

Author ORCID Identifier

Jung-Gyu Kim 0000-0002-9869-2636

Mahrous A. M. Ali 0000-0001-9369-0765

Jong-Gwan Kim 0000-0002-2131-1946

Abstract

Experimental and numerical analyses were conducted to investigate the effect of an eccentric loaded contour hole on a rock mass. In the concrete blocks used for the analyses, detonating cords were placed at the centre of the blast hole and eccentrically against the wall of the blast hole. PFC^2D and AUTODYN were used for the numerical analyses, and the results of these software showed that an eccentric decoupled charge can result in the directional development of fractures, thereby enabling the control of cracks in the opposite direction. Even though both types of blasting have identical decoupling indexes, the crack and fracture patterns were affected by the location of the explosive, tamping, and other conditions. The results showed that an eccentric charge holder can be applicable to control the fracture direction and the damaged zone. For an eccentric charge, the initial crack was generated at 0.01 ms and expanded in the intended direction. For the eccentric charge, the maximum pressure at the area in contact with the blast hole wall exceeded that for the central decoupled charge by a factor of 5.5. Furthermore, the pressure in the intended direction was twice of that in the opposite direction.

Recommended Citation

Kim, Jung-Gyu; Ali, Mahrous A. M.; and Kim, Jong-Gwan (2020) "Effect of an eccentric decoupled charge on rock mass blasting," Journal of Sustainable Mining: Vol. 19 : Iss. 1 , Article 1.
Available at: https://doi.org/10.46873/2300-3960.1000