Research On Seismic Response And Seismic Reinforcement Measure Of Upstream Tailing Dam

Most of the tailings dams stack the saturated tailings sand, and the saturated sand is easy to liquefy under the seismic excitation, hence the tailings dam is prone to liquefy and lose stability, endanger the ecological environment in the downstream area. Therefore, study of tailings dam’s earthquake response, dynamic stability and earthquake liquefaction and putting forward the corresponding measures of reinforcement is very necessary and urgent.This paper carries out the research by setting an upstream tailings dam-Jijiezi tailings dam in Changning County of Yunnan Province as an engineering example, the upstream tailings dam seismic response, seismic liquefaction, the stability of the dam and seismic reinforcement measures etc is mainly included. The main content of the paper is:(1) the internal friction angle and cohesion index of the tailings and related materials are obtained through the research of the field test and laboratory direct shear tests of tailings material based on the engineering geological survey data of the Jijiezi tailings dam;(2) the seepage regularity of Jijiezi tailings dam is studied based on fluid solid coupling seepage and seepage theory of unsaturated soil theory;(3) the static stability of the Jijiezi tailings dam is studied by the classical limit equilibrium method and the strength reduction method of finite element;(4) the dynamic response of the Jijiezi tailings dam under the seismic load by using the time history analysis method, and the safety factor of dynamic stability of tailings dam under the seismic load is proposed;(5) the potential liquefaction zone of the Jijiezi tailings dam under seismic load is determined by using the Seed’s discriminant method of sand liquefaction;(6)the anti-seismic effect of different seismic reinforcement measures is studied, and relatively effective reinforcement measures are presented aiming at Jijiezi tailings.The results of this study show that:(1) the two-dimensional seepage calculation results are similar with the results of three-dimensional seepage when the tailings dam is in the normal condition; the value of the calculation of two-dimensional seepage tailings dam is generally less than that of three dimensional seepage when the tailings dam is in the condition of flood; the larger the saturated tailings zone is, the more obvious the effect the fluid solid coupling have on seepage;(2)the results of M-P method and strength reduction method is close to each other; limit equilibrium method is not suitable for the exact solution in location of potential sliding surface of the dam;(3) the response of Jijiezi tailings dam to inputted time-history load of earthquake is small, the tailings dam is stable, but the calculated minimum safety factor is smaller, the security reservation of safety of the tailings is not enough;(4) Jijiezi tailing dam has arised the liquefaction phenomenon under the seismic load of, but liquefaction has less effect on tailings dam’s stability.The creative work of this paper includes:(1) three dimensional finite element analysis is adopted to research the seismic response of the tailings dam, therefore the analysis result is more practical;(2) the relative effective are put forward according to the tailings dam’s potential instable area under the seismic load.