Study On Slope Stability Of Open Pit To Underground Mining In Tenglong Iron Mine

With the continuous development of open-pit mining,the mining area gradually approaches the designed maximum open-pit mining boundary,and the mine needs to transition from open-pit mining to underground mining.Under the action of underground mining effect,the stress and strain in rock and soil will change,and the change law of stress and strain is more complex than that of single open pit mining.In the process of transferring open pit mining to underground mining,the stability of slope is a necessary condition to ensure the smooth transition of mining.In this paper,based on the engineering background of Tenglong iron mine open-pit to underground mining,on the basis of the existing data analysis and field investigation of the mining area,using the means of theoretical analysis and FLAC3 D numerical simulation software,the stability of Tenglong iron mine open-pit slope under the influence of underground mining effect is studied.The main contents and achievements are as follows:Based on the field investigation and data analysis of Tenglong iron mine,the geological environment conditions,mining history and mining status are summarized.According to the lithology of the rock mass in the mining area,the stope slope in the mining area is divided into the west side slope zone(1),the south side slope zone(2)and the east side slope zone(3).The stereographic projection method is used to analyze the influence of the structural plane characteristics of the rock mass in the stope slope on the stability of the slope,and the possible failure forms of the slope are predicted.This paper analyzes the factors affecting the stability of open-pit mine slope,studies the stress field and displacement field of open-pit mine slope under the action of underground mining,and summarizes the deformation mode of rock mass and the overall failure mode of slope in the process of open-pit to underground mining.In this paper,the stability of the open pit slope in Tenglong iron mine is analyzed by using the limit equilibrium method and limit analysis method.The slope stability coefficients of zone 1,zone 2 and zone 3 are 1.259,1.310 and 1.275 respectively,The slope of open-pit mine tends to be stable under the condition of early open-pit miningFLAC3D numerical simulation software is used to establish a three-dimensional model of Tenglong iron mine from open-pit to underground mining,simulate and analyze the variation law of stress field,displacement field and plastic zone of the slope in the process of underground filling and slicing mining,and analyze the slope stability of the open-pit mine under the condition of underground mining.According to the simulation results of underground mining,the prevention and control measures of drainage and reinforcement are put forward for the safety production of Tenglong iron mine.At the same time,the real-time monitoring system of slope is established in the process of underground mining to evaluate the slope stability in time.