Mechanical Properties And Vibration Reduction Effect Of The Three-dimensional Vibration (Seismic) Isolated Device For Metro Surrounding Buildings

The operation of metro has brought vibration and noise to the surrounding buildings.Traditional vibration isolation devices reduce the vertical frequency of the structure by using thick rubber bearings or spring.In a large number of experimental studies and practical projects,the vibration isolation devices have shown vibration mitigation efficiency.In order to isolate earthquake and subway vibration at the same time,many scholars at home and abroad have combined horizontal isolation bearings with vertical vibration isolation bearings,and proposed three-dimensional vibration isolation systems.Most of 3D vibration isolation systems are tandem devices,but the smaller vertical stiffness makes them have the problem of limited bearing capacity.Further research is needed to solve the problem of better vibration mitigation efficiency and larger bearing capacity.In addition,the three-dimensional vibration isolation systems proposed are powerless to the vertical components of multi-dimensional earthquakes.Compared to horizontal isolation,it will even more amplify the response of the superstructure.At present,the research on this problem is not mature enough,and the mechanical performance of the isolation systems under the bidirectional loading needs to be further research.A novel three-dimensional vibration isolation device was proposed in this paper,and the horizontal and vertical mechanical properties of the device under different loading conditions were analyzed.The feasible region of the device’s parameters was investigated,and the influence of different parameters on the mechanical properties of the device was studied.Static tests and finite element simulation were carried out on the proposed isolation devices,and three 3D vibration isolated devices with 11°were selected for vibration tests to verify the vibration mitigation efficiency.Finally,the dynamic response of structure under the vibration of earthquake and metro was studied for a practical project.The main contents of this paper are as follows:(1)The structure and deformation mechanism of the novel vibration isolated device were introduced,and the mechanical properties of the device under different loadings were analyzed.In addition,the feasible region of the parameters based on the performance target was analyzed for the device.The parameters that affect the performance of the device were also analyzed.(2)Three test models with different inclined angles were designed and produced,the static tests under different loading conditions were carried out.The difference of the mechanical properties between the vertical vibration isolated bearing and the threedimensional isolation device was investigated.Based on the experiment,a numerical model was established using finite element analysis software,and relevant loading cases were simulated and analyzed.The numerical results of the device were compared with theoretical and experimental results.The results show that the numerical simulation is reliable.(3)The vibration test was carried out to verify the vibration mitigation efficiency of the vibration isolation bearing.The rail vibration strength and spectrum characteristics were tested,and the characteristics and propagation law of the vibration caused by subway were analyzed.The difference of dynamic response between the isolated system and the fixed system was investigated.In addition,the comfort of the isolated system was evaluated.(4)A practical project in Shenzhen was selected to carry out the design of vibration isolation.The SAP2000 finite element software was used to establish the isolated and fixed numerical model of the project,and the dynamic response of the structure under the earthquake and metro was studied.The difference between the isolated structure and the fixed structure was compared.