基于最优基小波的基桩弱损伤应力波检测

从提高小波分析与基桩弱损伤检测的匹配性入手，提出了基于最优基小波连续小波变换的基桩应力反射波无损检测方法。该方法首先引入膨胀参数把标准Marr基小波扩展为Marr基小波空间，增强了基小波选取的自由度；进而依赖工程目的和分析对象建立香农熵测度以确定Marr最优基小波；最后采用最优基小波对基桩检测应力波进行连续小波变换，模谱的局部能量集中指示了桩底反射。基桩动力测试数值实验验证了方法是可行、有效的，且最优基小波能够有效地提高弱损伤检测精度。

DETECTION OF SMALL DAMAGES IN FOUNDATION PILES USING OPTIMAL BASE WAVELET

A novel nondestructive testing method,derived from enhancing the adaptability of wavelet analysis to practical engineering issue,is proposed to detect small damaes of foundation piles.At first,a dilative parameter is introduced to produce a Marr base wavelet space by modifying the standard Marr wavelet.This significantly improves the flexibility of selecting appropriate Marr base wavelet to satisfy the requirements of small damage detection of foundation piles.Moreover,depending on theanalysis goal to detect small damage detection of foundation piles.Moreover,depending on the analysis goal to deteit small damage and the analysis objece of stress wave,a Shannon entropy measure in wavelet transform field is adopted to choose the optimal base wavelet from Marr base wavelet space.Finally,the stress wave is analyzed by continuous wavelet transform with the optimal base wavelet,and the concentrations of local energy in the wavelet transform module spectrum indicate the features of refection stress wave induced by damages in foundation pile.The feasibility and effectiveness of the propose method are verified in the numerical experiment of dynamic testing to detect the integrity foundation piles,and especially the optimal base wavelet is demonstrated to be able to effectively improve the detection precision of small damages in foundaition piles.