Research On Stability Analysis And Prevention Measures Of Slope During Mining Hanging Wall Ore By Shrinkage Method

During the transition period from open-pit mining to underground mining in open-pit mines,it is possible to stabilize the production of the mine by actively implement to stope for hanging wall ore under the premise of ensuring the safety and stability of the open-pit slope.Based on the engineering background of an open-pit mine hanging wall ore mining,the slope stability in the process of mining hang wall ore with shrinkage method is analyzed by FLAC^3D numerical simulation software;Ore mining hang wall ore by shrinkage method is discussed,which may inducing the types of slope geological hazards,The paper propose relatively prevention measures aiming the different types of slope geological disaster and discuss the slope stability under the joint action of the prevention measures.The main research work of the paper as follows:?1?According to the calculation method of various boundary pillar widths and the engineering geological background of the certain open-pit iron mine,the K.B.Lu Pei brezhnev's estimation formula is determined as the optimal boundary pillar width calculation method in this paper.Based on the K.B.LuPei brezhnev's formula,the boundary pillar's width theory range for the mining of the hanging wall ore is calculated.Considering the operability in the actual construction,the boundary pillars in the four groups of numerical simulations are determined in this theoretical interval width.?2?Using the FLAC^3D numerical simulation software,the changes of plastic zone stress and displacement of surrounding rock after sequential mining of the first,second and third district mining room in each set working condition was analyzed,the influence of hanging wall ore mining on the stability of open-pit slope is minimized when the width of boundary pillar and intercolumn is equal to 16m and 10m respectively.Through the FLAC^3D numerical simulation software embedded safety factor solver,the slope safety coefficient of the three district mining room is calculated under the conditions that the boundary pillar and the intercolumn width were equal to16m and 10m respectively,which are less than the safety reserve coefficient and the slope is in the unstable state.?3?Based on the relevant domestic and foreign literature,the stress distribution of slope sxz axis,szz axis,sxx axis of slope and the displacement of slope monitoring point are analyzed under the influence of boundary pillar width and intercolumn width are analyzed.The types of geologic hazard of slope caused by boundary pillar and column instability are proposed.?4?Aiming at the possible geologic hazard types of slope,three kinds of slope prevention measures are proposed,including bolt,anti-slide piles and grouting.By using FLAC^3D numerical simulation software,the mining process of the three district mining room under the combined effect of the three prevention measures was simulated.Compared with unprevention conditions,the change of plastic zone,stress distribution and displacement law of the surrounding rock after mining in the three district mining room were compared and analyzed.It was found that under the conditions of prevention measures,the stability of the slope after mining in the three zones was promoted.The safety factor of the slope after preventing is calculated and it is obtained that it is larger than the safety reserve factor,and the prevented slope is in a stable state.