Study On The Dynamic Characteristics Of The Pie Base Is Olation Structure Considering The SSI Effect On Soft Found Ation

At present, most of the building structures are designed on the assumption of the rigid foundation and passive control design, and less consideration of the impact of the foundation on the dynamic response characteristics of the overall structure. But there have been many studies show that:AS considering the influence of SSI effect, which leads to changes in the dynamic characteristics of the upper structure and the soil, then leading to under flexible foundation for failing to show under the assumption of rigid foundation structure of the optimal control effect. Based on the paramenters from model test, integral three dimensional finite element models considering dynamic response of isolation and non-isolation structure on rigid and soft interlayer foundation were established based on ABAQUS. The elastic half space simplified model has been optimized based on above. Main contents and conclusions are:(1) Integral three-dimensional finite element model of pile-soil-isolated and non-isolated structure on rigid and soft interlayer foundation were established. Results of model test and numerical calculation were mainly compared, and indicates under the condition of rigid foundation, In addition to certain conditions, the amplification coefficient law is consistent. Under the condition of soft interlayer foundation, with the peak acceleration increasing, the deviation of the peak at the top of pile caps and the soil surface becoming small gradually. The intension of the motions are weakened when passing the interlayer. It proves the natural isolation effect of soft interlayer foundation is well.(2) The law of the isolation structure seismic response was studied through comparing the results of the models on different kinds of foundations. Overall, natural frequency of isolation structure is reducing with the severity of the foundation soil from firm to soft, and the damping ratio increases significantly. The influence on the response of isolation structure is different when the foundation is different.(3)Based on the existing simplified calculation method of the isolation structure dynamic characteristics, simplified analysis model of pile-base isolation structure was established. Results from this simplified method were compared with those from the model test. It verifies the simplified calculating method can effectively predict the dynamic characteristic and the seismic response of the isolation structure in considering pile-soil interaction.