Study On Deformation Mechanism Of Mine Slope Joint Based On Key Block Theory

In recent years,with the continuous expansion of the open-pit mining area,the stability of open-pit slope rock mass gradually becomes prominent,which makes it difficult for the mine to produce safely and efficiently.However,there is few research on the relationship between joint deformation mechanism and slope stability,so it is very important to study the slope stability and joint deformation mechanism under different joint parameters.Taking the rock slope of Yanshan Iron Mine as the research object,the theoretical analysis and numerical simulation are combined to study the shear deformation mechanism of the slope joint.According to the actual geologic survey,Shape Metri X 3D is used to make statistical analysis of the dominant joint surface of the slope,and the dominant structural surface group which can generate the key block is determined according to the stereographic projection and vector operations.Combined with 3DEC numerical simulation,the stability of slopes under different joint development degrees of open-pit mines was studied,and the change of stability coefficient of critical blocks under different parameters of sliding surfaces was analyzed.The mechanism of joint deformation was discussed.The research shows:Rock samples were collected from the Yanshan Iron Mine,and the cohesion of the jointed rock was 0.248 MPa and the internal friction angle was 27.31 ° measured by laboratory tests in rock mechanics.The quality of the jointed rock mass was evaluated by RMR method.Statistical analysis of the production parameters of jointed and fractured rock collected by the slope scanner shows that the four dominant joints.According to the combination of the dominant joints,three optimal joint combinations that can cut the key blocks are identified.By analyzing the results of 3DEC numerical simulation,the more joints develop in the slope,the greater the displacement of the key blocks toward the slope under the action of gravity,and the maximum displacement has an exponential relationship with the number of joints on the line per unit length.When the inclination angle of sliding surface increases(less than the slope angle),the stability coefficient of the key block decreases,and when the inclination angle of the sliding surface is parallel to the slope angle of the slope,the stability coefficient of the critical mass decreases to the minimum.And the degree of shear sliding deformation of the joint surface is maximum.When the cohesion and internal friction angle of the sliding surface increase,the stability coefficient of the key block increases.At this time,the shear deformation of the joint surface due to the sliding of the key block decreases.