Dynamic Response Analysis And Reinforcement Measures Of High Tailings Dam Under Earthquake Actio

China is rich in mineral resources.With the rapid growth of the economy,the demand for mineral resources has rapidly increased,resulting in the construction of a large number of new tailings dam.In recent years,the stable operation of tailings dam and the surrounding environmental protection have received attention,and the overall operation of tailings dam has gradually stabilized.However,the damming materials of tailings dam are extremely special,the tailings dam are under serious threat to the safety of production under earthquake action.Thus,It is of great significance to study the dynamic response of tailing dam and the stability of the dam body under earthquake and to propose effective reinforcement measures.Seepage and seismic action are the main factors affecting the stability of tailings dam.A tailing dam in Yunnan Province was used as the background of the study,and based on Geostudio software,the dynamic response,liquefaction region,dynamic stability and the influence of reinforcement measures on the stability of tailings dam under earthquake were studied,the main research contents and results of the paper are as follows:(1)Based on the relevant design data of tailings dam,the calculation model of tailings dam with dam height of 160 m is established.Based on the seepage theory and the unsaturated soil flow-solid coupling theory,the seepage law of the tailing dam is analyzed.Consider the effect of seepage action on tailings dam,the static stability of tailings dam is studied based on Duncan-Chang model and limit equilibrium method.The results show that the saturation line does not escape from the initial dam slope,and the buried depth of the accumulation dam is sufficient.The initial stress of the dam is the smallest at the top of the dam and the largest at the bottom of the dam,showing a compressive state;the stability coefficient of tailings dam calculated by different limit equilibrium methods meets the requirements of the specification.It is concluded that the tailings dam is in a stable state under static action.(2)Taking the results of static analysis as the initial conditions,based on the equivalent linear model,the stability of tailings dam under earthquake action was studied.The computation results show that the maximum value of the downstream and vertical dynamic displacement is 0.691 m and 0.46 m respectively.As the height of stacked dam increases,the relative acceleration along river and vertical direction of tailings dam increases,so the seismic response at the top of stacked dam should be paid more attention.The area of liquefaction is the junction of sedimentary beach and upstream water level surface.The minimum average safety factor method is used to calculate the safety factors of dynamic stability of tailings dam under normal conditions and flood conditions under earthquake,which are 1.459 and 1.239 respectively.The horizontal permanent deformation of the tailings dam is greater than the vertical permanent deformation.The horizontal permanent deformation is the deformation of the accumulation dam to the downstream position,and the vertical permanent deformation is the settlement of the top of the accumulation dam.(3)Based on the results of dynamic analysis,it can be seen that the top of the stacked dam is the weak part.The method of laying geogrid about 1/3 of the distance from the top of the stacked dam is adopted to strengthen the tailings dam,and the dynamic response of the tailings dam is analyzed when the spacing of reinforcement is 2m,3m,4m,5m and 6m.The results show that reinforcement measures will not change the seepage law of tailings dam;The relative acceleration of the stacked dam top after reinforcement decreased slightly compared with that without reinforcement,but the relative acceleration of the initial dam top did not change significantly compared with that without reinforcement.With the decrease of reinforcement spacing,the minimum safety factor of tailings dam gradually increased.Reinforcement can effectively inhibit the permanent deformation of the dam body,but too small reinforcement spacing can not significantly improve the seismic stability of the dam body.By comparing the influence of different spacing of reinforcement on permanent deformation and minimum safety factor of dam body,the optimum spacing of geogrid is determined to be 3m.