Propagation Performance Recognition Analysis Of Blast-induced Vibration On Shallow Tunnel

In this paper,based on the safety monitoring project of the South-South tunnel excavation blasting of Dalian subway project,to conduct on-site monitoring of blasting vibration, combined with lots of the first measured data,it makes a analysis to the the performance of blasting seismic wave propagation. In order to carry out proper selection of blasting parameters and blasting method, in which the blasting effect is optimum and the impact to the surrounding structures can be reduced to minimum.In view of this, this paper studied the following aspects:Simple statistical analysis of the measured data, build South-South Tunnel blasting vibration strength Sadaovsk prediction model; Using FFT transform analysis the blasting vibration signal of the overall spectrum; At the basis of introducing wavelet theory, application of Matlab programming language, the blasting vibration signals that contained interference and noise are de-noised by wavelet analysis; With wavelet and wavelet pocket analysis of the measured blasting vibration signals, and the traits of the blasting vibration signal distribution indifferent frequencies is gotien.Through the above analysis, we can draw the following conclusions:(1) Through the FFT transform.we can see that,blasting seismic wave frequency mainly concentrated in between20-100Hz, vibration frequency is greater than the general structure (5-1OHz), can ensure the safety of the surrounding structures.(2) The frequency of blasting seismic wave in vertical direction is slightly larger than the horizontal frequency, the possibility of harm is greater than the vertical to the structure in the horizontal.(3)The blasting vibration signals are analyzed by wavelet, the signal energy distribution is relatively wide.The frequency of the measuring point in three directions roughly in the same range, and each band dominant frequency showing the cross-cutting nature.(4) When the distance between explosion center and the measuring point is the same, increase the maximum single dose,the frequency of the blasting vibration signals is lower, which is not conducive to the safety of buildings, so we need to select the appropriate maximum single dose in In the process of construction.