| The seismic simulation shaking table can reproduce the actual ground motion acceleration time history,and it is a test equipment to test the damage mode and failure mechanism of the structure under the action of earthquake.If the design parameters of the vibration table power machine are unreasonable,it will affect the working performance and accuracy of the equipment,and will also cause vibration and noise pollution to the surrounding environment.In this thesis,based on the engineering background of the 5m×5m seismic simulation shaking table planned to be built by Shijiazhuang Railway University,the foundation of the shaking table is designed and studied.Firstly,the lumped parameter method recommended in "Code for Design of Power Machine Foundation" is used to optimize the design parameters of the shaking table foundation,and the influence of the eccentric arrangement of the test specimen and different site conditions on the maximum response of the shaking table foundation is analyzed.Under the condition of constant foundation mass,the optimal length,height and width ratio relationship under the premise of ensuring that the maximum response of the shaking table does not exceed the limit is analyzed;In the optimal length,height and width proportional relationship,the minimum mass under the premise of ensuring that the maximum response of the shaking table does not exceed the limit is analyzed;When the specimen is eccentrically arranged,the maximum response of the foundation is far greater than that of the non-eccentric arrangement;Silt,fine sand,coarse sand,and cohesive soil are used as foundation soil,and the dynamic response of the foundation caused by the shaking table test is too large,so it is not suitable to directly build the shaking table foundation on it.Secondly,the influence of the pile foundation on the maximum response of the shaking table foundation is studied.The results show that when the pile foundation is arranged at the four corners of the shaking table foundation,it is beneficial to reduce the dynamic response of the foundation;when the total cross-sectional area of the pile foundation remains unchanged,appropriately reducing the pile diameter can effectively reduce the dynamic response of the reaction foundation;soft soil foundation is suitable for Using the combination of reaction foundation and pile foundation,the shock absorption effect is obvious;for sites with good foundation conditions,it is not suitable to add additional pile foundations.Finally,the static analysis,harmonic response analysis and time history analysis of the shaking table foundation are carried out using the finite element model,and the results are compared with the results of the lumped parameter method.When analyzing the data control points of the foundation model,it is more reasonable to select the corner points at the top of the foundation pier when the actuators work in three directions at the same time;When designing the foundation,it is advisable to reinforce the pit where the vibrating table is placed,especially the concentrated force point of the actuator;Comparing the results of the harmonic response analysis and the lumped parameter method,the natural frequencies of the two are close,the displacements are not much different,and the graph trends are the same;Using various field seismic waveforms,the model is subjected to time-history analysis of the force,and it is obtained that the displacement peak value of the model foundation is higher than that of the harmonic response analysis and the lumped parameter method. |
