Study On The Performance Of Rubber-concrete Composite Periodic Vibration Isolation Barriers

With the rapid development of urban rail transit,the environmental vibration induced by trains is becoming more and more obvious.Vibration generation,propagation attenuation laws and their treatment have become one of the important research topics.When the track vibration reduction measures and the building vibration isolator cannot be implemented or the expected vibration reduction effect cannot be achieved even though the measures were adopted,the application of the transmission measures is another choice.Because of the band gap characteristic of periodic structures,that is,it can completely block the vibration propagation within the band gap range,so the vibration isolation barrier can be designed periodically to realize the blocking of vibration within specific frequency band.Considering the above background,in this thesis,a systematic research was carried out which combine theoretical analysis,experimental test and numerical simulation.The main research contents include:1.Taking two-dimensional and three-dimensional periodic structure as the research object,the influence of their geometric on the band gap distribution of periodic structure was investigated.By comparison and analysis,a type of dominant periodic structure with a wider vibration isolation frequency band was proposed referred to the frequency range of train-induced environmental vibration.2.An experimental device was designed and developed,which can be used to apply impact excitation inside soil layers in the laboratory sandbox.The depth of excitation location and impact force can be changed,and the impact force signal can be recorded.3.The principle experiment of the rubber-concrete periodic combined vibration isolation barrier was carried out.Under different excitation source burial depths(soil surface,underground depth 0.2 m,0.4 m,0.6 m,0.8 m),the vibration energy distribution of the layer surface and the vibration reduction effect of the vibration isolation barrier were obtained.4.The optimally designed prefabricated rubber-concrete periodic vibration isolation barrier was applied to the actual engineering finite element model of track-tunnel-stratum-period barrier to obtain the expected vibration isolation effect of its engineering application.The amplitude attenuation coefficient and insertion loss of three different depth rubber-concrete periodic vibration isolation barriers were studied.