The Analysis Of Slope Stability In An Open-pit To Underground Mining In Certain Iron Mine

When surface mining finished, mine will turn to underground mining, it influences the stability of surface slopes which will directly determine the mine construction and the safety of producing. Based on research results and progress about surface mining to underground mining at home and abroad, combining with the geological and topographical conditions of certain iron mine and the technical requirements of sublevel caving method, this paper calculate and analysis different mining phases at north first western area by using numerical simulation and calculate the stability of surface slopes according to shear strength reduction theory. Finally, the paper predicts the inflow of water in mine area.The main achievements of this thesis are listed as followings:1. Based on the geological and topographical data of mine and the technical requirements of sublevel caving method, the author established the 3-Dimension geological model by using MIDAS-FLAC3 D technology.2. Calculating and analyzing the features of stress and strain on different mining phases of sublevel caving method and different positions, evaluating the stability of the slope; the stability got better after backfill.3. Analyzed the stability of slope by using shear strength reduction theory. Using self-made shear strength reduction method the author calculated the upper wall and foot wall slopes’ stability of different mining phases, from the results, we can conclude that the stability of the upper wall slope and foot wall slope decreased incessantly, the stability get better when the goaf is filled.