A Study On Seismic Attenuation Barrier Based On Periodic Structure

Earthquake is a natural disaster that poses the greatest threat to human life and property.At the same time,China is one of the countries with the strongest seismic activity,the most frequent earthquakes and the most severe earthquake disasters.Earthquake movement will release a huge amount of energy to make the ground produce strong movement,and cause the destruction of all kinds of buildings and facilities,including collapse and all kinds of secondary disasters.So reducing the damage of seismic waves to all kinds of buildings and facilities is of great significance in earthquake prevention and disaster reduction.At present,the main seismic attenuation measures are to improve the seismic resistance and seismic isolation capabilities of buildings and various facilities.Few attenuation and control measures for seismic wave energy are realized from the propagation route.The phononic crystal(microscopic periodic structure)in solid state physics uses its periodic structure to attenuate the elastic wave.Inspired by this,the use of periodic structures to shield seismic waves has also been introduced into the field of civil engineering.In order to realize the attenuation of the low frequency component of the seismic wave in a large frequency range,the periodic structure embedded in the bedrock is studied according to the local resonance phononic crystal mechanism to realize the broadband zero band gap.Firstly,the band gap calculation is performed on the simple square scatterer model by the plane wave expansion method,and the results are compared with the finite element software COMSOL Multiphysics simulation results to verify the correctness of the finite element software simulation.The cross-shaped steel column scatterers are then calculated using COMSOL Multiphysics to obtain an ideal zero band gap of 0-19.5 Hz.In order to obtain the low-bandwidth band gap and the periodic structure that effectively attenuates the seismic wave,in this paper,the parameters of the periodic structure unit cell are analyzed respectively,including the effects of scatterer height,lattice constant,filling fraction and scatterer material on the zero band gap of the periodic structure.In this paper,the parameter analysis of the overall periodic structure is carried out.The effects of lattice constant,periodic number,incident direction and scatterer angle on seismic wave attenuation performance are also discussed.For the area where the bedrock is too deep,this paper proposes to embed the scatterer on the artificial concrete floor that buried in the ground and verify its seismic attenuation performance.Considering the feasibility of engineering applications,this paper proposes a scheme to invert the periodic structure anddiscusses the influence of the thickness of the concrete floor on its attenuation performance.This paper also compares the attenuation performance of different mark concrete scatterers and steel scatterers on seismic waves.In order to improve the intensity of the scatterer during it works,it is proposed to connect the scatterers to each other to improve the seismic resistance of the periodic barrier.At the end of the paper,the Chi-chi seismic wave data is used to analyze the transient response of the two forms of bedrock and two kinds of scatterers of the periodic structures.