中文摘要：

针对反射波法测桩局限性,用频率-初速度法测量桩的动刚度。将桩的动刚度用于区分夯扩沉管灌注桩中上部绝对缩颈和相对缩颈,间接反映夯扩头的大小,为选择静载试验桩提供依据。通过与同条件下正常桩的反射波曲线及动刚度对比,当反射波曲线异常或动刚度明显偏低时,桩底部完整性、沉渣厚度或桩端持力层性状异常。通过对比缺陷桩加固前后的反射波曲线和动刚度值,并将其与其他同条件下正常桩对比,可检验缺陷桩的加固效果。

英文摘要：

By means of comparing the reflected curve and the dynamic stiffness with those of perfect piles under the same conditions,abnormalities of the reflected wave curve or of obvious low dynamic stiffness would be found from the concrete defect in the lower pile,from the bottom sediment thickness or the characters of pile bearing stratum.Through investigating the changes of the reflected curve and the dynamic stiffness before and after reinforcement and comparing the reflected curve and the dynamic stiffness after reinforcement with those of perfect piles under the same conditions,the reinforcement effect can be inspected.