Study On Slope Stability Of Faults And Goafs In Gongchangling Open-pit Mine

The shallow mineral resources of the current mine have been exhausted,which brings new challenges to the open-pit mine.Open-pit mining has to develop in depth and under complex geological conditions.The existence of interrupted layers and mined-out areas seriously threatens the safe production of open-pit mines.Past engineering practice experience shows that slopes containing faults and slopes containing mined-out areas are the two types of slopes with the most instability and the most destructiveness.At present,due to the lack of in-depth and systematic research on the stability characteristics of fault-containing slopes and the influence of mined-out areas on fault-containing slopes,how to analyze the stability of faultcontaining slopes and study the influence of mined-out areas on fault-containing slopes.It is a thorny problem to geotechnical engineers.The thesis is based on the analysis of the stability of slopes containing faults on line 4 and 6 in the Laoling mining area of Gongchangling Open-pit Mine.The research content is based on the measured fault occurrence form in the mining area,and the deformation and failure mechanism of slopes containing faults on line 4 and 6.the influence of the mined-out area on the slope slippage with faults,the comparison of related geometrical and mechanical parameters of the faults,etc.have been comprehensively and systematically analyzed and studied.FLAC3D and GEO-SLOPE software is used for simulation analysis,and the research results obtained are as follows:The quality of the rocks was graded through relevant geological reports and field test data,and the overlying rock mass from 0 to 22 meters in the mining area was classified as the weathered area;the limit balance method and the finite element method were used to compare and analyze the 4 and 6 lines in the project.The stability of the slope containing faults,the stability coefficient of the slope and its potential sliding mode are obtained,which provides a reliable basis for the formulation of the early mining plan of the mine slope;for the common downward slope,when there is an empty area at the bottom of the slope,Existence will change the slip mode of fault-containing slopes,and summed up the composite shear slip mode of"fault-both sides of the goaf";the existence of the goaf greatly reduces the stability of faultcontaining slopes.After the empty area,the safety factor of the 4-line slope decreased from 1.96 to 1.82,with a decrease of 7.14%,and the safety factor of the 6-line slope decreased from 2.12 to 2.01,with a decrease of 5.18%.The fault dip,fault slope distance,the thickness of the fault has an influence on the stability of the slope.The stability of the slope increases with the increase of the inclination of the fault and the distance between the slopes of the fault.The thickness of the fault has little influence on the stability of the slope.The analysis of the simulation results verifies the stability of the slope.The engineering experience law that stability changes with the geometric parameters of the fault;in double faults parallel to the slope,the left and right faults will cause stress redistribution,and only the fault on the side closest to the slope directly affects the slip failure form of the slope;The idea of "a certain change" is proposed to divide the slope into optimized area and to-be-optimized area to optimize the optimized area and the to-be-optimized area.Finally,it is determined that the upper step angle is optimized from 55° to 58°,and the lower step angle is optimized.Optimized from 55° to 60°,the final slope angle was determined to be 46°,which met the safety design requirements of the mine.