基于强震响应过程信息的大坝损伤识别研究

Damage identification for a concrete dam based on its seismic response process information

大坝遭遇强震后的破坏程度诊断是大坝安全评价的重要问题,大坝在强震中的损伤发展过程和发展路径破坏过程对于大坝安全评价同样具有重要的价值。针对这一问题,提出利用大坝在强震过程中的响应时程数据,对损伤部位、不同部位发生初始损伤的时间次序以及损伤程度采用基于小波变换的相关性分析进行识别的思想和技术,提出了基于移动时间窗的初始损伤时刻识别的阈值指标。并通过有限元仿真和振动台模型试验对所提出的方法进行了验证。结果表明,基于移动时间窗的损伤预警指标可以清晰识别出初始损伤时刻,并且利用小波变换将信号分解为不同频带上的信号值来检测信号的奇异点,还可判断结构的损伤位置及不同部位发生初始损伤的时间次序。

Damage identification is an important problem for a concrete dam’s safety evaluation after strong earthquake, while its damage development process or its failure process developing path are also valuable for its safety evaluation. Here, several novel methods utilizing time history data of the dam’s seismic response were proposed to identify its damage locations, damage level and time sequence of initial damage in different parts based on wavelet transform’s correlation analysis idea and technique. A damage threshold value index sk was proposed to recognize initial damage time instants based on the moving time window. The effectiveness of the proposed methods was verified through finite element simulation and shaking table model tests. Results showed that the damage early warning index based on the moving time window can clearly identify initial damage time instants;the wavelet transform is used to decompose a signal into signal values in different frequency bands, detect the signal’s singular points, and determine damage locations and time sequence of initial damage in different parts.