Damage Evolution Mechanism of Extraction Structure During Mining Gently Dipped Orebody by Block Caving Method

The layout of single transportation level and multiple production levels in one panel made it possible to mine gently dipped orebody by block caving method. However, with the collapse of the orebody in the main sublevel, the ground pressure damage of the extraction structure in the vice sublevel presented some specific characteristics. In order to study the damage evolution mechanism of ground pressure in extraction structure during the process of mining gently dipped orebody, a numerical simulation model was established by using finite difference software FLAC^3D, Mohr–Coulomb strength criterion was adopted in calculation. The stress state of the extraction structure in the vice sublevel after each step was monitored and analyzed separately. The research results show that: undercutting in the main sublevel can aggravate the ground pressure damage of the extraction structure in front of an advancing undercut front in the vice sublevel while undercutting in the main sublevel can reduce the probability of secondary occurrence of ground pressure damage in the vice sublevel. The results are beneficial to the guidance of mining gently dipped orebodies in block caving method.