Due to certain geological characteristics (high thickness, rocky properties), some underground coal mines require the use of explosives. This paper explores the effects of fragmentation of different decks detonated simultaneously in a single borehole with the use of numerical analysis. ANSYS/LS-DYNA code was used for the implementation of the models. The models include an erosion criterion to simulate the cracks generated by the explosion. As expected, the near-borehole area was damaged by compression stresses, while far zones and the free surface of the boundary were subjected to tensile damage. With the increase of the number of decks in the borehole, different changes in the fracture pattern were observed, and the superposition effects of the stress wave became evident, affecting the fragmentation results. The superposition effect is more evident in close distances to the borehole, and its effect attenuates when the distance to the borehole increase.
Fei Liu, Shengli Yang, Huayong Lv and Jinwang Zhang — 1.) School of Energy and Mining Engineering, China University of Mining & Technology, Beijing 100083, China 2.) Coal Industry Engineering Research Center of Top-Coal Caving Mining, Beijing 100083, China
Jhon Silva — Department of Mining Engineering, University of Kentucky, Lexington, KY, 40506, U.S.A.
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