Dynamic Characteristics And Resonance Effect Of Foundation And Building Based On Micro Vibration Monitoring

With the advance of urbanization,city housing land became more and more nervous,buildings was forced to the direction of high-rise,the prior research about characteristics of micro vibration of foundation and buildings have been unable to meet the current needs,and their resonance effect for building aseismic plays an important influence.So this paper believes that the research on the dynamic characteristics and the resonance effect of the foundation and the building based on micro vibration monitoring has a certain theoretical basis and practical value under the new situation.In this paper take the foundation and building as the research object,their dynamic characteristics and resonance effects were studied through the theoretical formula derivation,software simulation and field test methods,and the main content and conclusions as follows:(1)Effect of elastic modulus,Poisson's ratio and density on the natural vibration frequency of the single stratum was simulated by Abaqus finite element software,and the results are compared with the theoretical formula,we find that the vibration frequency is positively correlated with elastic modulus,but negatively correlated with Poisson's ratio and density.The Abaqus simulation results and theoretical calculation results are quite different,however,they have the same trend when the elastic modulus,Poisson's ratio and density changing;The paper deals with the changes of longitudinal wave velocity,shear wave velocity and thickness affected foundation of predominant frequency and H/V spectral ratio peak by using ModelHVSR software.We found that in the same strata above the bedrock,with shear wave velocity increasing,the predominant frequency of foundation will increases as well,on the other hand the longitudinal wave velocity increasing and the shear wave speed decreasing will cause the H/V spectral ratio peak increases,the deeper strata has lower sensitivity when the wave velocity changing.(2)Through the finite element software established a layered site model that the geological survey data had already clarified,the dynamic properties of the layered site are simulated so that we found the accuracy of the 3D model is larger than the two-dimensional model under the same condition of other parameters.(3)Fundamental vibration period,natural period in longitudinal direction,natural period in transverse direction,first-mode damping ratio,damping ratio in longitudinal direction and damping ratio in transverse direction are acquired by the high-rise microseism test and after the suitable microseism data processing method was selected by comparison.The relationship between these parameters and building's height and aspect ratio is studied,which can found that the basic natural vibration period is 0.01862 times as much as the height of the building in Fuzhou area,and the damping ratio of the building is not a single decreasing trend with the increase of the height.(4)The relationship between predominant frequency and H/V spectral ratio peak be analyzed through the microseism test results of foundation and buildings By using ArcGIS software to process the analytical results of the test,the plane distribution map of the predominant frequency and the H/V spectral ratio peak is obtained,so that the resonance effect of the foundation and building could be evaluated.Analysis that the foundation near the rock mountain,maybe its with large stiffness,the predominant frequency is much higher than others in the district and similar to the natural frequency of buildings on the foundation,so that make it at high risk of resonance.The farther away from the rocky mountains,the greater predominant period of foundation.is also be found.This study can provide some reference for the initial design and the resonance risk assessment of high rise buildings on the layered foundation.