Analysis And Study On The Stability Of High And Steep Slope In A Large Copper Mine In Sichuan

The open pit slopes have the characteristics of high height,steep slopes,and great instability hazards.In addition,the engineering geological conditions of mines are generally complex,and the stability of the slopes will change to a certain extent with mining,and even landslides,Geological disasters such as collapses seriously affect mine production efficiency and the safety of life and property of mine workers.Therefore,starting from the actual situation of the mine,the research on the stability of the open pit slope has certain practical value and theoretical significance.This paper takes a new large-scale copper mine in Sichuan as the background,on the basis of the collected engineering geological data,four typical geological sections are selected on the slope of the open pit,and the rock mass mechanical parameters of each typical section are determined.On this basis,using FLAC^3D numerical simulation software,numerical simulation of four typical slopes is carried out,and the stress,displacement,plastic zone,maximum shear strain increment and stability coefficient in the excavation process of each typical slope in natural state are analyzed in detail.At the same time,the stability of each typical slope under the action of heavy rainfall,the coupling action of heavy rainfall and the coupling action of heavy rainfall blasting was also analyzed,and the most unfavorable working conditions affecting the stability of the slope were determined.For unstable slopes,according to the failure form of the slope and the characteristics of the rock mass,anti-sliding piles and anchor cables are used to reinforce them.Different support measures are discussed from the two aspects of the cross-section size of the anti-sliding piles and the supporting positions of the anchor cables.Influence on slope stability,and finally determine the best support scheme.This paper takes theⅠ-Ⅰ’slope as an example,the trial calculation is carried out,and the grid size at the model slope is determined to be 1.5m*1.5m to meet the calculation accuracy requirements;As long as the calculated sliding surface is within the selected boundary range,the boundary size has little effect on the final result;The error between the FLAC3D numerical simulation results and the unbalanced thrust method calculation results is 1%.The FLAC^3Dnumerical simulation software is effective and feasible to solve the slope stability coefficient.The rock mass of theⅠ-Ⅰ’andⅡ-Ⅱ’slopes is complete,the rock mass is of good quality,and is in a stable state under the natural state,seismic force and blasting vibration;The rock mass in the strong-moderately weathered rock strata in the upper part of theⅢ-Ⅲ’slope is of poor quality,and it is in an unstable state under the natural state,the action of heavy rainfall,the coupling action of heavy rainfall,and the coupling action of heavy rainfall blasting vibration-Instability failure easily occurs in the area of moderately weathered rock formations;The weak interlayer rock mass of theⅣ-Ⅳ’slope is of poor quality,and it is in an unstable state under the natural state,the action of heavy rainfall,the coupling action of heavy rainfall,and the coupling action of heavy rainfall blasting vibration.Instability failure.When the anti-sliding piles are used to support theⅢ-Ⅲ’slope,the section size of the anti-sliding pile D=1.5m is the optimum section size for the support;After being supported by anti-sliding piles,the maximum displacement of theⅢ-Ⅲ’slope is greatly reduced,and the area of the plastic zone is also reduced.Significantly improved,theⅢ-Ⅲ’slope is in a stable state under all working conditions after being supported by anti-sliding piles.When using anchor cables to conduct support research on theⅣ-Ⅳ’slope,under the condition that the total number of anchor cables is certain,the arrangement scheme of setting up a row of anchor cables on each of the four slopes has the best supporting effect;After being supported by anchor cables,the displacement of theⅣ-Ⅳ’slope decreases,the shear failure does not occur at the free surface of the weak interlayer,the maximum value of the incremental shear strain decreases,and the slope stability coefficient is improved,theⅣ-Ⅳ’slopes are in a stable state under all working conditions after being supported by anchor cables.