扩径桩反射波检测的小波分析研究

WAVELET ANALYSIS AND STUDY OF REFLECTIVE WAVE DETECTION OF EXTENDING PILE

介绍了反射波法的波阻抗理论及其局限性,建立了扩径桩和桩周有坚硬夹层土的完整桩两种情况的有限元模型,分别研究了在不同扩径大小和土层弹性模量的情况下,采样点加速度的小波分解图的特征。发现当采样频率大于40 kHz时,扩径反射和桩低反射之间有一系列明显的高频率峰值可以作为两种缺陷反射波相区别的特征。其结论可以为实际工作参考,为波形反演研究提供着手的方向。

Presented the wave impedance theory of reflection wave method and its localization. Then the FE models of diameter-extended .piles and integrated piles with a hard soil layer surrounded were built. The wavelet transformation figures of the sampling point＇s acceleration were studied when these two models were different in bug＇s diameter and soil~ elastic modulus respectively. It was found that when the sampling frequency was bigger than 40 kHz, A group of wave crests in high frequency between the reflected wave of bug and the pile toe could be select to be the distinguishing character between these two models. The results can be a reference in the practice and provide a target in the inversion of the characteristic wave.