CAJ | 학술논문

鉴于反射波法在低应变检测中主要受较大长径比、桩侧土剪切模量及微小缺陷、桩顶非裸露自由等条件限制存在的局限性，而小波变换时频特性优良，适用于基桩检测信号中探测奇异成分，故通过建立三维轴对称有限元模型，对模拟信号进行小波变换后发现：对顶部裸露自由桩，小波变换可获取微小桩底或缺陷反射，可减小长径比、桩侧土剪切模量、缺陷面积的限制；通过平台激振，使平台在有效尺寸范围内实现对桩底的深度检测。
감우반사파법재저응변검측중주요수교대장경비、장측토전절모량급미소결함、장정비라로자유등조건한제존재적국한성，이소파변환시빈특성우량，괄용우기장검측신호중탐측기이성분，고통과건립삼유축대칭유한원모형，대모의신호진행소파변환후발현：대정부라로자유장，소파변환가획취미소장저혹결함반사，가감소장경비、장측토전절모량、결함면적적한제；통과평태격진，사평태재유효척촌범위내실현대장저적심도검측。
The sonic echo test is a regular nondestructive test,and the applications are mainly limited in testing piles with high length-to-diameter ratio,high soil shear modulus,small defect areas or with an inaccessible head condition.Wavelet transform (WT),however,has good time frequency characteristics,which is suitable for identifying the singularities of pile testing signals.Three-dimensional axial symmetric finite element models were used to simulate the testing,and the wavelet transform was employed to deal with the simulated signal data.It is found that for piles with accessible head condition,the wavelet transform can identify weak wave reflected from pile bottom or defects,then reduce the limitation of length-to-diameter ratio,soil shear modulus and defect areas.For pile with inaccessible head condition, the pile bottom can be identified by plate-excitation if the plate is within certain effective sizes.