Stability Analysis Of Open Pit Mine Slope Under The Underground Mining Based On FLAC3D

With the rising demand for coal in our country,The open pit mining of the majority of domestic open-pit mines has entered deep mining or turned into underground mining,Open-pit slope height and area of the formed constantly in the increased,Therefore,the stability analysis of open pit slopes is critical to the safety of open pit mines.This paper is based on the strength reduction method,combined with the northern slope of the No.2 mine in Anjialing,Using the FLAC3 D software,the Mohr-Coulomb constitutive model is used to study the influence of underground mining on the open pit slope,and it is concluded that when the mining is advanced,the slope is unstable and the area is prone to instability.The research in this paper can provide reference for the safe production of the No.2 mine in Anjialing.The main work of this paper is as follows :(1)The sliding form of open pit slope is summarized,and three methods for preventing slope slip are introduced: the method of reducing the sliding force to increase the anti-sliding force,the method of increasing the strength of the slope rock mass and the artificial reinforcement method;(2)From the four aspects of coal mining method,well mining boundary,well mining direction,goaf size and mining speed,the deformation mechanism of slope failure under underground mining is analyze;(3)Using FLAC3 D software,combined with engineering practice,the 3-D model of the northern slope of No.2 Mine of Anjialing Mine was established,and the force and deformation of the slope under the influence of gravity were simulated and analyzed;(4)Using FLAC3 D software,the excavation of No.9 coal seam was simulated,and according to the depth of excavation,the underground mining was divided into five working conditions,and the force cloud and displacement cloud map of each working condition were analyzed,and the strength reduction method was used.Calculate the safety factor of the slope of each working condition,and obtain the slope displacement and the trend of the force change through the lateral comparison,and determine the boundary position where the mining is stopped and the area prone to instability.