Analysis on characteristics of dynamic signal for bolt anchorage system

Based on the dynamic tests on models of a bolt anchorage system,the time-frequency analysis of dynamic signals for the bolt anchorage system was made,and the accurate signal characteristics were acquired through modern signal processing methods.It was shown that short-term Fourier transform of the signals could indicate the signal intensity in the phase plane and the reflected signal from the bolt bottom was clear but the reflected signal from the bolt impairment could not be identified.With increasing of the quantity of bolt impairment or level of bolts,the energy of the reflected signals increased.The distribution of energy of the signals could be obtained in time and frequency domains by calculating Wigner-Ville distribution.The reflected energy was different among the bolts with various impairments.The approximate position and degree of signal variation could be analyzed and compared with those of the integrity bolts.Wavelet analysis provided more diagnostic information about bolt anchorage quality and was more suitable for the identification of dynamic test signal for bolt anchorage system with impairments.