Study On Damping Problem In Seismic Dynamic Response Analysis Of Tailings

With the rapid development of the economy, the strength of the resources exploitation, followed by the increases of the number of tailings pond. In recent years, the accidents induced by the earthquake such as the dam break of the tailing reservoir and the waste residue and water infiltration have increased a lot correspondingly. For this reason, the research of the stability of the tailings pond under seismic action is particularly important, the selection of the damping is one of the key issues in the core. This thesis carried out the research entitled "Research of the Damping Problem in Seismic Dynamic Analysis of Tailings Pond". The main research results are as follows:(1)Based on the engineering geological conditions, hydro-geological datum and experimental data from indoor and outdoor, this paper took the Xiangchong tailings pond in Gejiu,Yunnan as research objects, generalized the strata in the tailings reservoir, built the three-dimensional finite element model, converted the model into FLAC3D for the dynamic calculation.(2)Based on the theory of structural dynamics and the model of concentrated parameters, each strata’s weight was concentrated at the top of the responding layer. Through establishing the kinematical equations of multi-particle and solving the generalized coordinate with decoupling of equation and the integrating Duhamel equations, we obtained the analytical solution of maximum displacement and acceleration of the tailings dam under the damping ratio of 0.05. Compared with the numerical solution under the same damping ratio, the difference in value of maximum displacement was 20 mm, Therefore the results of numerical simulation is reasonable.(3)It was showed that, when the different local damping ratio were applied in the calculation of the displacement and acceleration amplification factor of the tailings dam under the seismic action, the maximum displacement present a negative correlation relationship with the value of the damping ratio. Make the results of damping ratio of 0.05 for reference, the differences between the results of damping ratio of 0.02 and 0.03 were large respectively, while with the results of damping ratio of 0.04 were minor. The acceleration amplification factor presented normal distribution, and the dispersion and the peak value showed a negative relationship with the damping ratio. Using SPSS software to analyze the correlation and variation of the acceleration amplification factor, it was also showed that, the correlation between the damping ratio of 0.04 and 0.05 was quite high.(4)The displacement and acceleration amplification factor of the tailings dam calculated by Rayleigh damping were analyzed, and the results showed that the maximum displacement of this two kinds of damping model were close when considering the natural vibration characteristics. When the seismic wave frequency similar characteristics were considered, the results between the two damping models were similar too, while the former calculation results were larger than the later. There existed differential among the four damping model calculated results, which presented a normal distribution. The dynamic response of the dam body was most obvious, and the acceleration amplification factor had the same distribution regularity with the displacement.(5) Different damping model calculation results show that:With local damping model and the Rayleigh damping model, the dynamic response of the tailings level differences, but the displacement and acceleration amplification factor distribution is similar; Local damping model calculated the tailings displacement calculation results is less than the Rayleigh damping model, the calculation results show that local damping model is relatively conservative. In practical engineering, when using the local damping model for dynamic response calculation of tailings, should pay attention to the influence of different damping ratios on the calculation results; If the Rayleigh damping model is used to calculate the dynamic response of the tailings, the influence of seismic wave spectrum characteristics on the calculation results should be fully considered.