Study On Slope Stability Of Mine Pits And Its Influence On Water Stop Curtain Engineering

In this paper,based on the actual mining project of an open pit mine,the slope of the pit and the peripheral water curtain project in the final mining form of the second and third mining areas of the open pit mine are studied.Finally,based on the aforementioned analysis and evaluation,corresponding prevention and control measures are taken for the slope of the mine pit,and the stability of the slope of the mine pit after the prevention and control works and the influence on the water curtain are numerically simulated by Midas numerical simulation software.The main research contents and results of this paper are as follows:(1)Based on the stability of the slope of the pit in the second and third mining areas,a detailed description of the subsequent mining of the slope of the pit in the second mining area and the northern gang of the third mining area is given and the final mining form of the slope is given;in order to ensure the normal production of the open pit and to fundamentally reduce the drainage of the pit,water stop curtains are placed at the periphery of the second and third mining areas in the northern part of the open pit to intercept the diving of the fourth series pore space.(2)Stability analysis of the slope of the pit in the final mining form of the northern gang of the second and third mining areas was carried out.Firstly,a qualitative analysis was conducted and it was concluded that the slopes of the upper part of the Quaternary strata of the slopes of the two pits are less stable and are susceptible to deformation and damage,and will affect the water curtain;subsequently,representative sections of the slopes of the two pits were selected and the stability of the slopes of the two pits was calculated quantitatively using the Rizheng geotechnical software and the simplified Bishop method,and it was concluded that the stability coefficients of the slopes of the two pits are less than 1 under both natural and rainfall conditions,and The potential slip surface is located in the upper Quaternary stratum and the slip surface form is circular.(3)The stability of the slopes of the two pits under natural and rainfall conditions and the influence on the water curtain are analyzed and evaluated from three perspectives of displacement,stress and strain respectively with the help of Midas numerical simulation software;the numerical simulation results show that the slope displacement of the upper quaternary strata of the slopes of the two pits is large,the potential slip surface is circular,and the slope body slides along the surface of the gravel layer,and there is a potential slip surface at the foot of each level.The slope stability coefficients of the two pits are less than 1.The sliding deformation of the slopes of the upper part of the fourth layer of the two pits causes the soil in front of the water curtain to loosen,which causes the soil to be displaced in the direction of the pits,resulting in changes in the stress state of the soil.The state of the soil changes,and the soil before and after the water stop curtain is unevenly stressed,thus producing displacement deformation.(4)Based on the deformation and damage of the slopes of the two pits and the analysis of the influence on the water curtain,the corresponding prevention and control measures are proposed;the study adopts prestressed anchor cables to prevent and control the slopes of the upper fourth strata of the slopes of the two pits respectively,and the numerical simulation analysis of the stability of the slopes of the pits after the prevention and control works and the influence on the water curtain.The slope displacement is significantly reduced,the maximum slope displacement is in millimeter level,the potential sliding surface basically disappears,and the stress concentration phenomenon at the foot of the slope at all levels is obviously weakened;compared with before the prevention and control,the slope of the upper fourth system stratum changes from overall slip deformation to shallow surface damage,and the original through strain area obviously fades away;the calculated stability coefficient of the slopes of the two pits is greater than the comprehensive selected safety coefficient of 1.25,and there is sufficient safety reserve.The maximum displacement is only a few millimeters;the stability of the slopes and curtain of the two pits has increased significantly after the prevention and control.