| With the rapid development of China’s transportation industry,environmental vibration pollution induced by traffic load has become increasingly prominent,adversely affecting the physical and mental health of residents along the route and the structural safety of buildings,and how to control and reduce environmental vibration caused by traffic load is becoming the focus of widespread attention in today’s society.Due to its bandgap characteristics,periodic structural vibration isolation barriers can block and control environmental vibrations at specific target frequencies.Based on the calculation theory of vibration propagation and periodic structure bandgap,this thesis studies the bandgap characteristics of continuous barrier of periodic wave-resistance blocks,establishes a wave resistance block supercell model combined with the supercellular method,and analyzes the bandgap characteristics of periodic wave-resistance block defect states.In order to explore the vibration damping performance of wave resistance block,a vibration experimental platform is designed and built,and the continuous barrier experiment of periodic wave resistance block is carried out,which verifies the effectiveness of the bandgap characteristics of wave resistance block.By establishing a three-dimensional foundation soil model,the vibration damping performance of the continuous barrier of periodic wave resistance block under simple harmonic moving load is deeply studied.The main conclusions of this thesis are as follows:(1)The bandgap characteristics of the periodic wave resistance block continuous barrier composed of concrete as matrix,rubber as wrapping layer and natural soil as core were studied.When the band gap is mainly generated by the propagation of the vibration wave to the wave resistance block,the scatterer and the matrix composed of the core and the envelope cancel each other,and the local resonance mode is stimulated,and the vibration wave attenuation in the band gap interval is significantly higher than that outside the band gap.(2)The main factors affecting the complete band gap of the periodic wave resistance block are analyzed.Among the geometric parameters and material parameters of periodic waveresist block,the main factors affecting the complete band gap of periodic wavestop block include cell constant,wrapping layer thickness,core size,matrix density,core density,and elastic modulus of the wrapping layer.Through the analysis of the frequency response function of finite periodic wave resistance block in the orthogonal experimental scheme,it is verified that the periodic wave resistance block has a good damping effect in the attenuation domain.(3)By comparing the bandgap characteristics of periodic wavestop cell and wavestop block supercell,it is found that the wavestop block cell and supercell have the same complete band gap.On the basis of wave resistance block supercell,when there is a single point defect at the center position of the periodic wave resistance block,the core material is missing,the cross-shaped core will produce defect bands,the core and wrapping layer materials are missing and the round core will not appear defective bands,and the change of the composition ratio of core and wrapping layer materials in the center position is the main reason for the defective bands.When there are multi-point defects in the periodic wave resistance block,the number and arrangement of the missing multipoint defects of the core material have no effect on the number of defect bands produced,and the lack of multi-point defects of the core and wrapping layer material will also not produce defective bands,but the number and arrangement of the missing multi-point defects of the core and wrapping layer material will lead to changes in the interval range of the complete band gap of the wave resistance block.(4)Design and build a vibration experimental platform that can be used to study the vibration damping performance of vibration isolation barrier indoors.Through the indoor model experiment of continuous barrier of periodic wave resistance block,it is shown that the periodic wave resistance block has a good vibration damping effect.In the designed experimental continuous barrier band gap interval,the vibration damping effect is more obvious than that outside the band gap interval,which verifies the effectiveness of the continuous barrier bandgap characteristics of periodic wave resistance block.(5)According to the main frequency of vibration caused by traffic load,a periodic wave resistance block with a cell constant of 1 m,a thickness of 0.05 m and a core size of 0.8 m is designed,and its complete band gap interval is 20.6～37.2 Hz.Under the same conditions,the vibration damping performance of the continuous barrier of periodic wave resistance block with a vibration frequency in the complete band gap interval is higher than that of the concrete wall barrier.Under the action of simple harmonic moving load,the vibration damping effect of wave resistance block is affected by the load moving speed,and according to actual needs,a specific wave resistance block layout scheme can effectively reduce the environmental vibration caused by moving load. |
