Comparative Study On Discrete Element And Finite Difference Simulations Of Marble Slopes In Yunnan Diantan

With the rapid development of computer technology,the numerical method gradually replaces the traditional qualitative judgment method and plays a great role in the quantitative analysis of slope stability,among which the FDM is one of the most widely used methods.However,in the study of mechanical problems of rock slope,due to the existence of many micro-cracks,joints and other discontinuities in rock mass,the FDM can not truly describe the discontinuity characteristics of rock mass,so there are some differences between the simulation and the actual situation of rock slope.On the other hand,the DEM has great potential in solving the problems of rock mechanics because it can describe the condition of rock mass well.In this paper,the marble slope on the west side of the south mining pit of Diantan Iron Mine in Yunnan Province is taken as the research object,and the influence of parameters variation in the simulation of DEM on rock mass strength is discussed.Three dimensional FDM and DEM are used to analyze the stability of the marble slope in the west side of the mining area,and the differences between the simulation results of the two methods are compared and analyzed.By comparing the stability analysis results with the slope displacement monitoring data,the advantages and disadvantages of the DEM and the FDM in engineering application as well as the errors caused by them are analyzed.The main insights are as follows:1.In the discrete element simulation,the strength of rock mass with single structural plane does not fully follow the theory of single weak plane.When the dip Angle of the structural plane is less than the internal friction Angle of the structural plane,the strength of the structural plane will not affect the strength of the rock mass,and the strength of the rock mass is controlled by the strength of the rock block,and the strength is consistent with the strength of the rock block.When the dip Angle of the structural plane is greater than the internal friction Angle of the structural plane,the rock mass strength is controlled by the strength of the structural plane,and the rock mass strength is the lowest at 45°,and the failure is most likely to occur.2.In the discrete element simulation,the strength of rock mass with single discontinuities does not completely follow the theory of single weak plane.When the inclination angle of discontinuities is less than the internal friction angle of discontinuities,the strength of discontinuities does not affect the strength of rock mass,and the strength of rock mass is controlled by and consistent with the strength of rock block.When the dip angle of the structural plane is greater than the internal friction Angle of the structural plane,the rock mass strength is controlled by the strength of the structural plane,and the rock mass strength is the lowest at 45°,and the failure is most likely to occur.2.Through the simulation of the DEM and the FDM,the safety factor of the marble slope can meet the requirements of the mine safety code under the natural condition and the rainstorm condition.3.The slope stability simulated by the FDM only shows the characteristics of typical sliding landslide or traction landslide,and does not reflect the sudden and rapid brittle failure characteristics of rock mass collapse.4.The process of slope stability simulation by the DEM is more similar to the step-by-step overturning rock slope collapse,with obvious brittle failure characteristics,and can more effectively reflect the displacement and deformation characteristics of the rock slope than the FDM.5.In engineering application,the safety factor calculated by the DEM is relatively smaller than that by the FDM;Moreover,the basic theory of the DEM is more consistent with the characteristics of the rock slope,and the theoretical error generated by using the DEM is smaller,and the simulation results are closer to the actual situation.