Analysis On Isolation Of Ground Vibration Induced By Vertical Excitation For Duxseal-WIB

The ground vibration generated by traffic load,engineering construction,machine operation,and other dynamic loads is known to induce environmental vibration pollution in the vicinity of the vibration source,which seriously influences the structural safety of buildings,and the normal production and life of human beings,especially the production and use of adjacent precision instruments that are sensitive to vibrations.To solve the problem,a kind of vibration screening material with high damping ratio,Duxseal,is creatively utilized as an active barrier in the free field.Based on the semi-theoretical and semi-analytical boundary element method(BEM),a soil-structure dynamic model is established,and the vibration screening characteristics of Duxseal is calculated and analyzed.Then,a newly designed barrier system,i.e.,the basic wave impeding blocks(WIBs)are drilled with multiple cylindrical holes which are then packed with Duxseal,is proposed to be used for vibration screening in the free field on the basis of the isolation complementary of Duxseal and WIB.To evaluate the isolation performance of Duxseal-WIB(DXWIB)under the vertical excitation,a set of field tests are conducted.The main contents are as follows:(1)Two dimensional(2D)analysis of Duxseal material as an active vibration isolation in elastic half-space foundation.Duxseal is firstly proposed to be creatively used as an active vibration barrier to isolate the vibrations in the free field based on its excellent damping ratio.Applying 2D semi-theoretical and semi-analytical BEM combined with thin-layer method(TLM),a soil-structure dynamic model is established,and the influences of the geometrical dimension of Duxseal and soil parameters on the vibration reduction for Duxseal are then discussed.After a parametric study,the differences of the vibration isolation between Duxseal and WIB are compared.The results show that Duxseal performed exceedingly well in reducing ground displacement amplitude especially for vertical displacement in the free field under harmonic vertical excitation.The effectiveness of the vibration isolation increases with the increase of the width,thickness,and embedded depth for the Duxseal material,within a certain range.Compared with WIB,the effectiveness of Duxseal in reducing the level of ground vibration is much more stable.(2)Three dimensional(3D)analysis of Duxseal material as an active vibration isolation in elastic half-space foundation.Based on 3D semi-theoretical and semi-analytical BEM,the vibration isolation effectiveness on ground displacement for different diameters,thicknesses and embedded depths of Duxseal in homogeneous and layered elastic foundation are calculated.Then,comparatively analyzing the influence of dimensional parameters of Duxseal and soil parameters on the vibration screening for Duxseal in 2D and 3D elastic foundation.Meanwhile,the correlation of the laws of vibration isolation between Duxseal and WIB is investigated,combining 2D calculation results.The results show that the effectiveness of the vibration isolation increases with the increase of the diameter,thickness,and embedded depth for Duxseal material,within a certain range.The influence of embedded depth of Duxseal and soil parameters on the vibration isolation for Duxseal are particularly significant.Additionally,the isolation laws pertaining to the increasing distance from the vibration source for Duxseal and WIB demonstrates a complementary phenomenon.(3)Vibration isolation characteristic for DXWIB.Based on the isolation complementary of Duxseal and WIB,a newly designed active barrier system,i.e.,WIB with incorporation of Duxseal,is proposed to be used for vibration screening.Conducting a set of field tests,the isolation effectiveness of the ground vibration subjected to the vertical excitation for DXWIB is compared with WIB and honeycomb WIB.Take the test data at the monitoring point 3 m away from the centre of vibration source for numerical fast Fourier transformation(FFT)and inverse fast Fourier transformation(IFFT),the performance of the vibration screening for DXWIB in time domain and frequency domain are further analyzed,and the vibration screening mechanism is then revealed.The test results indicate that DXWIB performed exceedingly well in mitigating ground vibrations induced by the vertical excitation,which significantly reduces the amplitude of ground acceleration and ground displacement.