锚杆系统动测信号的特征分析

利用实验室锚杆模型试验所测得的信号,采用现代信号处理技术对信号进行时频分析,得到具体、精确的信号特征。信号的短时傅立叶变换可在相平面表达信号的强度大小,并且杆底反射信号比较明显,但不能反映缺陷处的反射信号。另外,锚杆缺陷越多,反射信号的能量也越大。通过Wigner-Ville分布计算和分析,可得到信号的能量在时间和频率中的分布情况,不同损伤的锚杆的反射能量是不同的。通过与完整锚杆信号相比较可以发现信号变化的大致位置及变化的程度。小波分析提供了更多关于锚杆锚固质量的特征信息,更适合于处理锚杆系统有损伤情况下动测波形的识别。

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.