Monitoring and analysis of the impact of small internal tunnel blasting vibration on the hilltop

In order to control and evaluate the impact of blasting vibration on the buildings on the hilltop,vibrations of constructions on the top of the Daping mountain are monitored and analyzed.The hilltop ground surface before and after the working surface has empty amplification,the vibration velocity magnification factor,which is about 1.5~2.0,is larger in the range of 0~40 m,and then gradually becomes smaller,and in the region of 40~80 m the velocity magnification factor is about 1.0~1.5.The seismic waves of the non-hole area surface are in line with the Sodev's empirical formula while the seismic waves of the hole area are not.The vibration dominant frequency,which is about 16~96 Hz,is mainly concentrated in the low frequency band when the seismic waves are spreaded in the surface,and the dominant frequency gradually decreases with the increasing of the distance.However,before and after the working face the attenuation degree of the dominant frequency is different: the measuring point dominant frequency in front of the working face is slightly less than in the back of the working face.