Study On The Stability Of Downdip Soft Rock Slope Of The West Slope Of Zanihe Open-pit Coal Mine

The downdip weak layer has a great impact on the development of stripping and mining engineering and the stability of the slope in open-pit mine,especially temporary boundary slope and final boundary slope,under the influence of downdip weak layer,too much coal resources are overburdened in the slope.it is necessary to put forward a technically feasible slope stability control scheme,which increases the resource recovery rate while taking into account the safety of production.In this paper,the west slope of Zanihe open-pit coal mine was taken as the research background.Based on the analysis of engineering geological characteristics of slope and past slope deformation datas,this paper determined the occurrence position of the downdip weak layers;by constructing the slope stability difference function,it was revealed that the quantitative relationship between the selected position of the section and the stability of the slope with downdip weak layer;combined with the engineering geological conditions of the west slope,the plane position of the main sliding direction of the west slope was determined;based on the rigid limit equilibrium method,the morphological design of the temporary boundary slope and the final boundary slope of the west slope was carried out,and anchor cable was proposed for reinforcement;CAD and combined with the dichotomy method were used to calculate the axial force required for anchor cable reinforcement,and the parameters such as the installation angle,the space,the number of rows,and the length of anchorage section required for anchor cable reinforcement were determined;the numerical simulation method was used to study the slope instability mechanism and the reinforcement effect of anchor cable.The research results show that the weak layers in the west slope are located at the interface between quaternary and base-rock,and the 9th coal floor;the plane position at 11° to the vertical slope section line is the plane position of the main sliding direction of the west slope;the stability coefficient of the temporary boundary slope of the west slope is 1.052,and when the minimum cover height of the inner dumping is 458,the stability coefficient is 1.112;the stability coefficient of the final boundary slope of the west slope before anchor cable reinforcement is0.821,and when the calculated stability coefficient is 1.100,the required axial force of anchor cable is 9700 k N,anchor cable installation angle is 30°,the anchor cable space is 2m,the number of anchor cable rows are 15,the row space is 4m,and the length of the anchor cable segment is14m;The failure mode of temporary boundary slope is sliding-shear failure,and the genesis mechanism is push-type;the failure mode of final boundary slope is sliding-shear failure before anchor cable reinforcement,and the genesis mechanism is traction-type;after the anchor cable is reinforced to the final boundary slope,the existence of the anchor cable significantly reduces the instability displacement of the slope and makes the stress distribution in the slope uniform.The paper has 61 figures,14 tables and 61 references.