基于小波变换的侧面激振法对在役基桩检测

Pile-Side Excitation Integrity Testing for Existing Foundation Based on Wavelet Transform

通过建立桩-土-柱-梁三维有限元模型,分别对柱侧进行横向、斜向下45°、竖向激振,对模拟信号小波变换后,研究了不同的激振形式、激振-检波配置方式对识别桩底深度的影响。结果表明:在激振侧面检波,信号干扰最小;检波器宜在激振高度附近,且激振点应远离上部结构,以减小上部结构的干扰;相对于横向激振,竖向激振与斜向激振时桩底反射更明显,在实际检测中以采用斜向激振为宜。

Three-dimensional （3-D） finite element model of pile-soil-pillar-beam system was used to simulate the testing, and wavelet transform was employed to deal with the simulated signal processing. The effects of the excitation-receiver configuration and the excitation mode, including transverse direction, longitudinal direction and oblique direction, were investigated. It is good to place the receiver in the side wall of the excitation face. Keeping the receiver close to excitation height and a certain distance from the superstructure can reduce the in- terferences of the superstucture. Compared to transverse direction exciation, longitudinal and oblique direction exciations are much better to identify the pile length. To strike in oblique direction is strongly recommended be- cause of much convenience in oractical oroeedure.