基于小波变换的某重力拱坝背水坡转异裂缝序列的分析

Analysis of Abnormal Crack Series of Downstream Slope of Gravity Arch Dam Based on Wavelet Transform

裂缝转异诊断对分析大坝安全稳定运行有重要意义。将小波变换应用于大坝裂缝转异分析中,并结合某重力拱坝背水坡裂缝X18-1的实测数据,分别从小波系数图的过零点和极值点、多尺度下模极大值线及奇异性变化角度讨论其与裂缝转异时刻的关系,最终综合判断出裂缝的转异时刻。分析结果表明,小波系数图、模极大值线和奇异性均可反映裂缝的转异,但各自独立的诊断结果不完全相同,综合分析可准确判定裂缝的转异时刻,为裂缝转异诊断提供了新思路。

The diagnosis of crack abnormality has important significance for the analysis of the dam safety and stable operation.The wavelet transform method is applied to analyze the dam crack abnormality.Combined with the X18-1crack measured data of downstream slope of a gravity arch dam,this paper discusses the relations with crack abnormality time from the zero-crossing points and extreme points of wavelet coefficients,wavelet modulus maxima lines under multiscales and changes of singularity.Finally,a comprehensive judgment of the time of crack abnormality is carried out.The results show that the wavelet coefficients figure,modulus maxima lines and singularity all can reflect the crack abnormality,but the separate diagnoses are not identical;a correct judgment about the abnormality time can be made by comprehensive analysis.Therefore,this study provides a new idea for diagnosis of crack abnormality.