Study On Static And Dynamic Stability Of Tailing Orebody Slope Based On DEM-FDM Coupling Analysis Method

In this paper,a three-dimensional numerical model is established for the tailing slope in Xiangchong,Jielao City,Yunnan Province,as the research background.Two different numerical analysis methods,discrete(DEM)and continuous(FDM),are selected to combine the advantages of the two methods in analyzing the stability of tailing slopes,and the discrete-continuous coupled analysis method is used to analyze the intrinsic mechanism of tailing slope damage from the fine viewpoint.The analysis is then compared with the ultimate equilibrium method.The main research work and the results obtained in the paper are as follows:(1)A triaxial numerical test was established using PFC3D to obtain the stress-strain curves of the tailings particles,and by comparing the stress Mohr circles to make them consistent with the macroscopic strength parameters,the fine parameter values corresponding to the same macroscopic parameters of cohesion and internal friction angle as those of the tailings material were calibrated,and in addition,the numerical test was compared with the indoor test results to verify the accuracy of the calibration results of this numerical test.The accuracy of the numerical test calibration results was verified.(2)Based on the fine parameter calibration,the fine strength reduction law was derived by combining the macroscopic strength reduction method,and the reduction relationship was written into a strength reduction function code and carried out discrete-continuous coupling analysis,which finally verified the reliability of the coupling model.(3)Based on the strength reduction method and the limit equilibrium method,the analysis of the fine damage mechanism and macro stability of the tailing slope under the action of static force shows that: the velocity and displacement of the particles increase during the formation of the slip surface of the tailing slope,and the velocity will remain unchanged after the formation of the slip surface,while the displacement continues to increase;the contact force between the particles shows a trend of first increasing and then decreasing,and the peak value appears at the time of the formation of the slip surface.The contact force between particles shows a trend of increasing and then decreasing,and the peak occurs when the slip crack surface is formed,and the shear stress and the main stress also show an increase first,but then enter the stage of residual stress;analysis of the contact of particles in the measuring ball shows that: in the whole process of slope damage,the particles in the coupling area first appear to be crowded and then separate,and the bond stress between particles is destroyed when the slip surface penetrates the measuring ball;the pore space in the slope body decreases first during the formation of the slip crack surface of the tailings slope,and then the pore space in the slope body decreases as the damage continues to increase.As the damage continues to increase,the porosity gradually increases.(4)The dynamic response and stability analysis of the tailings slope under dynamic action based on the intensity reduction method and the limit equilibrium method shows that: at the elevation,there is an obvious amplification of acceleration and tendency to table effect,and the heavier impact is at the interlayer;when the seismic intensity is higher,the dynamic response is more intense along the upper part of the slope table and near the coupling area,and the damage is mainly at the shallow slip surface;the material with higher elastic modulus is more affected by the lateral ground shaking.The material with higher modulus of elasticity is subject to more significant transverse ground shaking and more intense acceleration response;the coupling wall around the coupling area has an inhibiting effect on the seismic wave propagation;the coupling area has a certain amplifying effect on the PGA amplification coefficient of the nearby continuous unit medium;under the action of earthquake,the internal structural damage of the slope body is more serious,and the deep shear damage range and the top tensile range are more concentrated.(5)Based on the limit equilibrium method and the strength reduction method,the stability calculations of the slope of the object washing tailings unde r static and dynamic effects were carried out by using the numerical analysis software Slide,PFC3D and FLAC3D software,respectively.The difference with the Bishop method is 5.63% under the static action,and the difference with the Spencer method is 2.4 2% under the dynamic action.Overall,the difference is within 6%,which indicates that the coupled DEM-FDM analysis method has high accuracy in analyzing the stability of tailing slopes.