Research On Dynamic Characteristics Of Upstream Tailings Under Earthquake Load

Tailings dam is the major hazards source for metal and non-metal mines. The proportion of tailings in normal operation is low in our country and disasters and secondary disasters often happen. It not only threatens the safety of people’s lives and property, but also affects the ecosystem environment. Earthquake is one of the most important factors that causes tailing liquefaction and induces instability. Therefore, establishing dynamic model of the tailings under seismic load, analyzing dynamic characteristics of the tailings and revealing the instability mechanism of the tailings under seismic load lay a theoretical foundation for the in-depth study of tailing dam stability, deformation and seismic measures and it has important research significance and practical value. In this paper, applying the methods of theoretical analysis, model test and calculation, treating tailings and shaking table model test as the basis and considering theoretical analysis and numerical calculation as the leading to research on dynamic characteristics of tailing dam under seismic load.Firstly, applying the shaking table test system to carry out experiment of pore water pressure growth law of different severe tailing sand in different load application frequency and different amplitude, revealing the close relationship between overlying tailings severe, input power load frequency and pore water pressure under dynamic load conditions, obtaining the relationship curve of pore water pressure of tailings under dynamic load and vibration time; applying the electric-gas dynamic three axle testing system to carry out the increasing model test of tailings pore water pressure, through the damped least square method, Fortran language and VC++ technology to develop parameter inversion software of the increasing model of tailings pore water pressure, the parameters of the pore pressure increasing strain model are calculated, and provide the basic data for the further study on dynamic properties of tailings dam.Secondly, using the tailings sands which have the same pore pressure regularity to carry out seismic model test of dynamic characteristics of tailing dam under different slope ratio and model test study of tailings dam failure to analysis the variation law of acceleration, pore water pressure, earth pressure and displacement with the vibration time, tailings dam elevation and slope ratio under different input peak acceleration, reappearing the process of higher pore pressure, lower strength, local failure instability, and ultimately dam failure under the dynamic loads, revealing the instability mechanism of the tailing dam under seismic load and mud depth evolution regularity in the process of dam failure and accumulation pattern after dam failure are reappeared at the same time.Third, considering the dynamic triaxial tests on three tailings and tailing shaking table model test results, starting from the Biot dynamic consolidation equation, considering the pore pressure increasing regularity and the deformation law after liquefaction to establish the tailings flow solid coupling dynamic model, applying this model to calculate the dynamic characteristics of the tailings dam under different slope, saturation line height and peak acceleration, the stability of tailings is worse if the dam slope and input peak acceleration are greater and the saturation line is higher, the calculation method is applied to engineering, to check the dynamic stability of the present tailings dam, and through calculating the different heightening and expansion program of the tailings to select the most stable expansion for guiding the engineering practice.