Application Of Viscoelastic Artificial Boundary In Dynamic Response Analysis Of Tailings Dam

Tailings dam is a kind of hazard with high potential energy. Earthquake damage of tailings dam may lead to disastrous consequences. Energy dissipation effect of seismic wave in far field is an important factor in seismic response of tailings dam.Under earthquake action,selecting boundary types have a great influence on the results of seismic response. Therefore, it is meaningful for deeper dynamic response analysis of tailings dam to research application of viscoelasticity artificial boundary in this field. In this paper, the main research work is carried out as following:(1)Firstly, basic situation and research status of dynamic response analysis of tailings dam as well as viscoelasticity artificial boundary are summarized. Secondly,in the second chapter, derivation process of the two-dimensional and the three-dimensional formulas of viscoelasticity artificial boundary are introduced, and the equivalent parameters formulas of the viscoelasticity artificial boundary element are introduced. Furthermore, the equivalent viscoelasticity artificial boundary element in the ABAQUS are realized, and the classical lamb problem by ABAQUS is analyzed to verify that equivalent viscoelasticity artificial boundary element is more accurate, which can simulate energy dissipation effect of seismic wave in far field better. Finally, the theory of dynamic response analysis of tailings dam is introduced, equivalent linear viscous constitutive of tailings sand is realized based on the secondary development of ABAQUS.(2)According to an investigation data of a flat ground type tailings dam, the corresponding 2D model is built. The seepage calculation results by using ABAQUS obtain saturation line of the tailings dam as well as initial stress in dynamic response computation of tailings dam.(3)Viscoelasticity artificial boundary and fixed boundary are used respectively for dynamic response analysis of the tailings dam. On the basis, the dynamic response of the horizontal acceleration, the horizontal displacement, the dynamic principal stress, the dynamic shear stress and the entire strain energy is analyzed.Through the above study the following main conclusions are drown:(1)That boundary types have great influence on dynamic response of tailings dam. Compared with the fixed boundary, if using the viscoelastic artificial boundary,the maximum values of dynamic response analysis of tailings dam reduce 15%~25%because of the energy absorption effect of the viscoelastic artificial boundary.However, it is not significant that viscoelastic artificial boundary absorb energy during the starting four seconds of earthquake, the amplitudes of time history curve of dynamic response of tailings dam are contiguous. Because the volume of tailings dam is very large, during initial stage of seismic action, the viscoelastic artificial boundary on the tailings dam absorbs less energy which radiate out from scattering wave source.(2)Parameter R can take value in a wider range, it indicate that viscoelastic artificial boundary have good robustness when it is used for dynamic response of the tailings dam.(3)There is a significant positive correlation between the dynamic elastic modulus of foundation and K2. The larger the K2 value, the smaller the ground flexibility, the smaller dynamic shear strain in the foundation of tailings dam. If the K2 value is larger, the viscoelastic artificial boundary absorption energy is smaller.The eventual results show that the amplitude reduction of dynamic shear stress is smaller.