基于频谱分析和小波包熵值技术的压浆密实度检测与分析

Detection and analysis of grouting compactness based on frequency spectrum analysis and wavelet packet entropy technology

基于河北省某桥梁检测项目,为研究预应力混凝土桥孔道压浆质量的缺陷,使用冲击回波法对共计41个孔道进行了检测,根据反射信号的特性得到孔道内压浆密实度的状况。根据不同压浆密实度缺陷边界面规则的5种有限元模型,提取时域数据进行快速傅里叶变换,拟合出压浆密实度和频率的关系式,并通过实际工程数据验证了有限元模型的准确性。针对缺陷分界处相同,缺陷边界面不规则的有限元模型,用小波包熵值技术对时域数据进行分析,得出缺陷尺寸的大小。结果表明:在缺陷边界面规则和缺陷边界面不规则的工况中,随着缺陷尺寸的减小,小波包熵值均会增大,实现了对缺陷分界处相同,但是缺陷尺寸大小不同的压浆密实度工况的区分,从而可以更加精确地对压浆密实度进行评估。

Based on a bridge detection project in Hebei province,in order to study the defects of the grouting quality of the prestressed concrete bridge channels,a total of 41 pipelines were tested using the impact echo method,and the grouting density in the pipelines was obtained according to the characteristics of the reflected signals.According to the five kinds of finite element models with different density of defect boundary surface rules,and perform fast Fourier transform on the extracted time domain date to fit the linear relationship between grouting density and frequency.And the accuracy of the finite element model through actual engineering data was verified.Aiming at the finite element models with the same defect boundary and irregular defect boundary surface,the wavelet packet entropy technology was used to analyze the time domain data to obtain the size of the defect.The results show that:in the working conditions of regular and irregular defect boundary surfaces,as the size of the defect decreases,the entropy value of the wavelet packet energy spectrum will increase.The grouting compactness working conditions with the same defect boundary but different size of the defect are distinguished,so that the grouting compactness can be evaluated more accurately.