Prediction of vibration waveform and a safety assessment of ancient buildings based on the equivalent simulation method of blasting load
Vibration produced by blast excavation of tunnels has a great influence on the safety of adjacent ancient buildings.To study the propagation law of blasting vibration waves,predict the ground vibration effect,and analyze the safety of adjacent ancient buildings,the dynamic response of Labuleng Temple under a blasting load was predicted using field measurements com-bined with numerical simulation analysis.The results show that(1)particle vibration velocity increases with explosive quantity,and attenuation ratio increases with vibration velocity,indica-ting fast and slow attenuation of high-and low-frequency vibrations,respectively.(2)Blasting load is applied to the elastic boundary or contour plane of tunnel excavation,and dynamic simula-tion results show that their vibration velocity is consistent at intermediate or far distances larger than 40 m;therefore,applying the load on the contour plane of the tunnel excavation is reasona-ble.(3)Volume waveform at the free interface of blasting seismic wave is reflected to form Ray-leigh waves propagating along the surface.Combined with the numerical simulation of the propa-gation law of seismic waves in the mountain,a complex vibration zone is formed in the mountain by reflection and superposition.(4)When the local seismic wave reaches the Labuleng Temple,radial,vertical,and synthetic vibration velocities have peak values of 0.000 672,0.000 448,and 0.000 807 cm/s,respectively,which are far less than the safety vibration control standard of ancient buildings.