Study On Three-dimensional Seepage And Dynamic Characteristics Of Tailings Pond For One-step Constructed Dam

China’s annual mine beneficiation produces a huge amount of tailings,most of which are stored in tailings ponds.In the event of a dam failure,tailings ponds can pose a great threat to the safety of life and property of downstream residents and important facilities.The use of one-step constructed dam tailings ponds is vigorously promoted in China due to their high safety,however,the dynamic characteristics of one-step constructed dam tailings ponds under seismic action have not been studied in depth.This thesis takes a one-step constructed dam tailings pond as the research object,and uses finite element software to conduct three-dimensional seepage analysis,static analysis and dynamic analysis of the tailings pond,the main contents and conclusions are as follows:(1)The three-dimensional numerical simulation of seepage was carried out for the one-step constructed dam tailings pond,and the distribution of infiltration surface,total head and hydraulic specific drop were analyzed.It was found that the seepage field of the one-step constructed tailings pond is quite different from other types of tailings pond,and the characteristics of the seepage field of the one-step constructed dam tailings pond were obtained,in addition,the seepage data were provided for the dynamic analysis.(2)The nonlinear static analysis was carried out for the one-step constructed dam tailings pond,and it was found that the larger values of the maximum principal stresses in the tailings pond of the one-step constructed dam is distributed at the bottom of the rockfill dam and the bottom of the tailings accumulation area.The larger values of the minimum principal stress is mainly distributed at the bottom of the rockfill dam.The maximum principal stress and minimum principal stress increase with depth,and the main stress in the tailings pond is compressive stress.Tensile stress only appears in the shallow range of the surface layer of the tailings pond.(3)The dynamic response analysis was carried out for the one-step constructed dam tailings pond,and the regions with larger distribution of dynamic shear stress and dynamic shear strain were obtained.Higher dynamic shear stress in rockfill dams,lower dynamic shear stress in tailings sands and in clay core walls.The dynamic shear strain is smaller in rockfill dams and clay core walls,and larger in tailings sands.Inside the tailings pond,the acceleration amplification factor increases with height.At the same depth,the amplification coefficient of tailings sands is greater than rockfill dams.(4)The permanent deformation analysis of the one-step constructed dam tailings pond was carried out,and it was found that the vertical deformation of the one-step constructed dam tailings pond was larger than the horizontal deformation.The permanent deformation of one-step constructed dam tailing pond is manifested in the form of large vertical settlement in the middle of the tailing stockpile area and the formation of low-lying areas,thus the deformation of the surrounding surface tailing sand towards the larger settlement.The greater the depth of tailings sand accumulation,the greater the surface settlement at that location.(5)The liquefaction zone analysis was carried out for the one-step constructed dam tailings pond,and the study found that the liquefaction zone of the one-step constructed dam tailings pond mainly occurs in the area with saturated water content at the end of the tailings sediment beach.The liquefaction zone of the one-step constructed dam tailings pond is larger in scope and deeper in depth.(6)The results of seepage and dynamic stability calculations of one-step constructed dam tailings ponds and other types of tailings ponds were compared and analyzed in depth,thus obtaining the similarities and differences of seepage field and dynamic characteristics.