Study On Vibration Isolation Performance Of Rigid Polyurethane Foam Continual Barrier With Bolting

With the rapid development of China's economy,environmental vibration caused by production,transportation and construction has become more and more serious,which has seriously affected people's daily life and work.The traditional continual barrier has achieved satisfactory results in mitigating environmental vibration.However,there are still some problems,such as poor stability,insufficient depth of embedding,poor vibration isolation effect of low-frequency,abnormal vibration amplification in the vibration isolation area.Based on the theory of resonance effect of barrier vibration isolation,a new kind of vibration isolation method of rigid polyurethane foam continual barrier with bolting was presented in this paper,and its vibration isolation performance was studied,and some practical application results were obtained.The main results are as follows:1.The basic principle of 3D finite element method is summarized,and the parameter design of finite element numerical analysis is discussed,including the size of the model,the size of the element,the step of the time integration,the rationality of the Rayleigh damping coefficient,the effect of the artificial boundary e.g.According to the shear wave velocity,wave length and the frequency range of interest,the model parameters needed in the whole modeling process are determined.2.Based on the theoretical analysis,the theory of the resonance effect of the vibration isolation barrier system is introduced,and the central problem of the influence of the bolt arrangement on the natural frequency of the barrier system is analyzed numerically.On the one hand,the influence of the width of the barrier system on the natural frequency of the barrier system is studied in the direction of the incident wave propagation.On the other hand,the parameters sensitivity analysis of bolt to barrier system is carried out.3.Through the establishment of three-dimensional finite element model of typical site soil and the application of ground vibration source harmonic load,the vibration propagation law of ground surface is analyzed numerically.The vibration displacement amplitude and the vibration displacement decay rate are taken as indexes to draw vibration displacement amplitude frequency curve and vibration displacement decay rate curve,the propagation attenuation law of vibration wave inthe soil free field is obtained.And compared with the measured data of the engineering site,the rationality of the numerical model is verified.4.Through the establishment of three-dimensional finite element model of soil-bolt-vibration isolation barrier,the vibration isolation performance of rigid polyurethane foam continual barrier with bolting and the concrete continual wall barrier under the ground vibration source harmonic load and the pile vibration source harmonic load respectively was investigated,the vibration vertical acceleration amplitude is taken as index to draw vibration vertical acceleration amplitude frequency curve,the vibration isolation performance of the two kinds of vibration isolation barriers are compared and analyzed.The vertical vibration acceleration amplitude attenuation coefficient is taken as an index to compare and analyze the vibration isolation effect of two kinds of vibration isolation measures on low frequency vibration.The research results of this paper can not only provide solutions for vibration problems such as urban ground transportation,elevated traffic,subway transportation,construction piling and so on,but also provide reference for vibration research and management in relevant areas.