Study On Isolation Barrier Based On Gradient Non-homogeneous Wave Impeding Block

The vibration influence of urban transportation and manufacturing production on the surrounding environment and countermeasures is one of the important subjects in the field of soil dynamics.Wave impeding block(WIB)vibration isolation system as an effective measure for vibration pollution control is applied in practical engineering gradually,but the previous studies mostly focused on the soil is single-phase elastic homogeneous foundation and the wave impeding block is single-phase solid homogeneous materials,few research have been on the vibration isolation performance of wave impeding block with materials properties that have a continuous variation along space relatively.Due to the fluid-solid coupling,the fluid-saturated porous media materials can lead to energy dissipation during vibration and has the similar damping effect;and the non-homogeneity of gradient non-homogeneous has a significant influence on the dispersion curves and attenuation curves,it can also cause energy dissipation in the process of environmental vibration.Therefore,in this paper,the author employed the characteristics of the fluid-saturated porous media and gradient non-homogeneous materials to investigate the isolation efficiency of wave impeding block with various materials such as single-phase solid homogeneous materials,single-phase gradient non-homogeneous materials,fluid-saturated porous homogeneous materials and fluid-saturated porous gradient non-homogeneous materials,and the work mechanism of reservoir gradient non-homogeneous and fluid-saturated isolation barrier is revealed,which provides a kind of vibration isolation system for the control of environmental vibration pollution problems caused by artificial vibration.The main contents of the paper are as follows:(1)Considering setting the single homogeneous wave impeding block in the elastic foundation,the mathematic model of problem is established.Based on the liner elastic theory,the calculation formulas of the foundation’s dynamic responses to surface and internal strip harmonic loads are build with the using the Fourier series expansion method,and the stress and displacement response at any point in elastic foundation and single homogeneous wave impeding block are obtained,which lays the foundations for the comparative analysis of the superiority of the vibration isolation effect with different materials properties wave impeding block vibration isolation system and single-phase homogeneous solid wave impeding block in the following article.(2)Based on the fluid-solid coupling in fluid-saturated porous media,a new type of foundation vibration isolation system is proposed.The fluid-saturated porous wave impeding blocks are set in an elastic foundation subjected to surface and internal strip harmonic loads.The Fourier series expansion method is used to build the calculation formulas of the foundation’s dynamic responses to surface and internal strip harmonic loads with the liner elastic theory and Biot’s model.With numerical examples,the vibration isolation effect is compared to that with conventional single phase solid wave impeding block,and the influences of parameters of fluid-saturated porous material including properties of solid phase,porosity,and properties of pore fluid on the foundation’s vibration isolation performance are analyzed.The results show that compared with the single phase solid impeding block vibration isolation system,the fluid-saturated porous wave impeding block vibration isolation system has more advantages.(3)Based on the gradient non-homogeneous material,a new type of foundation vibration isolation system is proposed.Considering setting the gradient non-homogeneous wave impeding block in the elastic foundation which subjected to surface strip harmonic load,using the Fourier transform and Helmholtz vector decomposition,the calculation formula of reverberation ray matrix method(RRMM)is established for two-dimensional transient response of elastic foundation based on the line elastic theory.Assuming that the material properties of gradient non-homogeneous wave impeding block have an exponential law distribution along the thickness-coordinate,by using numerical inverse Fourier transformation,the displacement and the stress are obtained.Via numerical examples,the effectiveness of vibration isolation of gradient non-homogeneous wave impeding block is compared to conventional single phase solid homogeneous wave impeding block,and the influences of physical and mechanical parameters including the gradient factor,the depth and the thickness of gradient non-homogeneous wave impeding block are analyzed.The results show that the gradient non-homogeneous wave impeding block can effectively reduce the vibration amplitude,and compared with the single phase solid homogeneous wave impeding block isolation system,gradient non-homogeneous wave impeding block isolation system has more effective and more flexible design..(4)Using the saturated porous soil model,which is more realistic than that the line elastic model,the isolation effect of fluid-saturated gradient non-homogeneous wave impeding block in a saturated foundations are studied.Based on the Biot’s model,using the Fourier transform and reverberation ray matrix method,the expression of displacement,stress and pore-fluid pressure of saturated soil in the frequency domain are derived.Via numerical examples,the isolation effect of fluid-saturated gradient non-homogeneous wave impeding block in saturated foundations are analyzed in detail.The results show that the fluid-saturated gradient non-homogeneous wave impeding block isolation system has more effective in saturated foundations,which provides a kind of vibration isolation system for the ground vibration control of saturated soil.(5)Combined with the coordinate transformation,the dynamic governing equations for elastic foundation and saturated foundation under a moving load are established respectively.Using the Fourier transform and reverberation ray matrix method,the calculation formulas of the elastic and saturated foundation’s dynamic responses in the frequency domain are derived to study the vibration isolation effect of single gradient non-homogeneous wave impeding block and fluid-saturated gradient non-homogeneous wave impeding block on reducing vibration induced by a moving load.Via numerical examples,the vibration isolation effect of single gradient non-homogeneous wave impeding block and fluid-saturated gradient non-homogeneous wave impeding block under a moving load are analyzed.