Experimental Study On Vibration Isolation Effect Of Rigid Polyurethane Foam Continuous Barriers

With the increasing speed of urbanization,environmental vibration caused by human activities such as transportation,industrial production,and infrastructure has become more and more serious.This has greatly affected people's normal production and life.Vibration is listed as one of the seven major environmental hazards.Therefore,it is necessary to study the vibration caused by these artificial vibration sources and their propagation and attenuation laws in the soil and related vibration isolation techniques.Barrier vibration isolation is an engineering method of installing one or more barriers between a vibration source and an area requiring vibration isolation.When the vibration wave propagates to the barrier,reflection and refraction occur,and the energy absorption effect of the barrier is added.Only a small part of the vibration wave can pass through the barrier,so that the vibration after the barrier will be greatly reduced to achieve the effect of vibration isolation.The barrier vibration isolation has been widely used in practical projects.In this paper,the effect of vibration isolation of different barriers is studied by model test.On the basis of the current research status of barrier isolation at home and abroad and the existing problems of barrier,the research content of this paper is put forward.First,it briefly introduces the theory of wave motion,analyzes the causes of barrier vibration isolation,and points out the significance of model test;Then,an experimental model box was set up indoors to study the propagation and attenuation of vibration waves under impact vibration;ground vibration and vibration in tunnel under the action of no barrier,polystyrene foam barrier,rigid polyurethane foam(insulation type)barrier and rigid polyurethane foam(imitation wood type)isolation barrier effect.The vibration attenuation of the ground under different vibration sources was analyzed.The vibration isolation effects of different vibration isolation measures on low frequency vibration were compared and analyzed.The main achievements of this paper are as follows.(1)The attenuation of the medium-high frequency vibration under the impact load is fast,while the low frequency attenuation is slow,and the peak acceleration decays with the distance as a negative power function.(2)Under the action of the ground vibration source,The polystyrene foam barrier has a good vibration isolation effect on the mid-high frequency,but has poor vibrationisolation effect on low-frequency vibration;the rigid Polyurethane foam barrier has the best vibration isolation effect on the medium-high frequency,in which the rigid Polyurethane foam(imitation wood type)barrier It has better vibration isolation effect on low frequency vibration.(3)Under the same working conditions,the peak vibration acceleration of the ground under the tunnel vibration source is greatly reduced compared to the ground vibration source,and the amplitude can be reduced by more than 50%.Therefore,a new type of vibration reduction concept can be provided.The vibration source can be transmitted to the deep soil by the vibration source transmission pile at the vibration source concentration point,and the vibration wave can be weakened by the damping effect of the soil to achieve the purpose of vibration isolation.(4)Rigid Polyurethane foam(imitation wood type)barrier has the best vibration isolation effect for low-frequency(10Hz-40Hz)vibration,and it can reduce the low-frequency vibration more than 41.57%.