Study On Blasting Seismic Response And Damage Evolution Law Of Masonry Structure

With the wide application of blasting technology,blasting seismic problem,as the main problem of negative effects of engineering blasting,has been paid more and more attention.The proportion of masonry structure building in China is quite large,and its seismic performance and structural integrity are poor compared with other structures.Therefore,by means of theoretical analysis,field test and dynamic finite element simulation,this paper systematically discusses the propagation characteristics of blasting seismic waves and the dynamic response of masonry structure under the action of blasting seismic waves,as well as the evolution rules of damage and cracking.The main research results are as follows:(1)Based on the columnar seismic wave propagation theory,the formula of vibration velocity and blasting distance of blasting seismic wave is established and the test data is used to verify that the blasting vibration velocity increases with the increase of blasting distance.Meanwhile,the attenuation rate of its vibration velocity varies greatly in different regions,controlled by the correction coefficient of burst pressure and the attenuation parameters of geology and topography.(2)The displacement,velocity and acceleration of the dynamic response of masonry structure are related to the amplitude and frequency of blasting seismic wave.Through the analysis of field scale model test data,the response displacement of masonry structure under the action of blasting seismic wave increases with the increase of floor.Time history analysis method based on three layers of masonry structure in different ideal sine wave amplitude and frequency under the action of the elastic response value curve analysis,masonry structure displacement and speed increased with the increase of seismic amplitude values of linear increase,and the seismic wave frequency response law of masonry structure is changed twists and turns,namely frequency close to the masonry structure is the first main frequency of blasting seismic wave following close displacement and velocity response values.(3)The damage and cracking process of blasting seismic response of masonry structure is not only related to the amplitude and frequency of seismic waves,but also related to the number and combination of blasting seismic waves.The response law of masonry structureis basically consistent with the elastic law when the single seismic wave is acted on,while the repeated action of blasting seismic wave is related to the sequence of its action.When the main frequency of blasting seismic wave is 8HZ and 60 HZ,the damage and cracking effect of masonry structure is the most obvious.