Transient Stress Signal Analysis Based on Wavelet Transform

The stress signal of soil during vibrating compaction is unstable and transient saltation signals accompanied by strong noise. To study the joint time-frequency property of the soil stress signal during vibrating compaction,wavelet transform method for de-noising and detection is proposed. By multiresolution wavelet decomposition,the reconstructed signal keeps useful frequency band but suppress some high frequency band. That separates the noise from the signal efficiently. For singularity analysis,the time of the stress appearance and the time of the stress peak arrival are obtained by detecting two kinds of the modulus maximum of the wavelet transform coefficients. Thus the impaction time from the stress appearance to peak arrival can be calculated. It is of great importance for analyzing the distribution and the propagation law of the stress in the soil.