| Since the 20 th century,the first time that the study of the impact of the blasting vibration on the buildings near the mine has accumulated a large number of observations of the blasting seismic effect,and blasting vibration safety regulations were established accordingly.Today,the mechanism and safety criterion of blasting vibration effect on buildings are still hot topics.Firstly,the blasting vibration test was carried out at Hubei Petrochemical storage and transportation company,and the blast vibration signal of the blasting vibration signal was analyzed by MATLAB wavelet packet energy analysis.Then,ANSYS / LS-DYNA dynamic finite element analysis software was utilized to simulate the modeling and blasting numerical simulation of the building.The dynamic response and safety criterion of the blasting seismic wave to the masonry structure and the RC frame structure were investigated.The main research results are as follows:(1)The vibration monitoring results show that the peak velocity of the vibration velocity in the horizontal direction decreases with the increase of the height of the monitoring site.However,the peak velocity of the vibration velocity in the vertical direction increases with the increase of the floor,which displays a high-level amplification effect.(2)The spectrum and energy distribution of the blasting seismic wave signal from different floor with the fast Fourier transform and wavelet packet analysis.The frequency of the blasting vibration signal is mainly concentrated 0~120Hz.With the increase of the floor,the signal frequencychanges from 25 ~ 50 Hz to 10 ~ 30Hz;The energy is mainly concentrated on lower frequency blasting seismic wave,which is below 78.12 Hz.When the energy ratio increases from 0 ~ 19.53 Hz along the floor,the proportion of energy above 39.06 Hz is obvious reduction.Other bands have little change in energy distribution.(3)The height of the building was found to have a substantial significant effect on the natural frequency of the building by using ANSYS/LS-DYNA.Second,four,six,eight layers of masonry structure natural frequency respectively are 31.37 Hz,16.15 Hz,8.71 Hz and 8.71 Hz.Masonry structure and frame structure of the natural frequencies is increased with the increase of the number of floors is reduced,the same number of floors masonry structure inherent frequency is obviously higher than that of RC frame structure.Explanations why the masonry structure blasting seismic wave resistance is weaker than RC frame structure from the angle of the frequency.Through the latest architectural structure in the load code for the basic natural vibration period of experience formula to calculate the natural frequencies of the frame structure and the results of numerical simulation error in 10% ~ 15%.(4)Two solid models were built for actual four-storey masonry and RC frame building in LS-DYNA.The effects of the amplitude,basic frequency and duration of blasting vibration waves on response of structure were discussed.Simulation results show that the largest response occurs on doors and windows and wall corner bottom of masonry building with blasting vibration,the response of structural increase of velocity amplitude and the increasing coefficient stay in step with the velocity increasing coefficient.The closer the frequency to the model,the greater the response of amplitude,it means that structure has a resonance effect.The impact of duration on the dynamic response and damage status is decided by whether the model exceeds the elastic limit into the plastic zone.(5)Safety standards of four-storey masonry range frequency from 0~10Hz?10~20Hz?20~30Hz?30~40Hz?40~50Hz under different vibration amplitude were given,which were obtained by defining critical failure state of the structural element. |
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